Merge branch 'master' of github.com:protocolbuffers/protobuf into ktExport

.gitignore

@@ -215,5 +215,10 @@ _build/
 .idea
 *.iml
 
+# Eclipse
+**/.settings
+**/.project
+**/.classpath
+
 # BenchmarkDotNet
 BenchmarkDotNet.Artifacts/

CHANGES.txt

@@ -21,6 +21,7 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   * Report original exceptions when parsing JSON
   * Add more info to @deprecated javadoc for set/get/has methods
   * Fix initialization bug in doc comment line numbers
+  * Fix comments for message set wire format.
 
   Kotlin
   * Add orNull extensions for optional message fields in Kotlin.
@@ -46,6 +47,8 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
     zone. If omitted or None, the function returns a timezone-naive UTC datetime
     (as previously).
   * Adds client_streaming and server_streaming fields to MethodDescriptor.
+  * Add "ensure_ascii" parameter to json_format.MessageToJson. This allows smaller
+    JSON serializations with UTF-8 or other non-ASCII encodings.
 
   Compiler
   * Migrate IsDefault(const std::string*) and UnsafeSetDefault(const std::string*)
@@ -63,6 +66,7 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   * Do not log/report the same descriptor symbol multiple times if it contains
     more than one invalid character.
   * Add UnknownFieldSet::SerializeToString and SerializeToCodedStream.
+  * Remove explicit default pointers and deprecated API from protocol compiler
 
   Arenas
   * Change Repeated*Field to reuse memory when using arenas.
@@ -80,6 +84,10 @@ Unreleased Changes (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
   * Generate narrower code
   * Fix https://github.com/protocolbuffers/protobuf/issues/9378 by removing
     shadowed _cached_size_ field
+  * Remove GetPointer() and explicit nullptr defaults.
+  * add proto_h flag for speeding up large builds
+  * Add missing overload for reference wrapped fields.
+
 
 2022-01-28 version 3.19.4 (C++/Java/Python/PHP/Objective-C/C#/Ruby/JavaScript)
 

CONTRIBUTORS.txt

@@ -100,3 +100,8 @@ Patch contributors:
   Andrew Paprocki <andrew@ishiboo.com>
     * Fixed minor IBM xlC compiler build issues
     * Added atomicops for AIX (POWER)
+  Nipunn Koorapati <nipunn1313@gmail.com>
+    * Provide a type alias field ValueType on EnumTypeWrapper
+    * Match service argument names to abstract interface
+
+

Makefile.am

@@ -544,6 +544,7 @@ java_EXTRA_DIST=
   java/kotlin/generate-test-sources-build.xml                                      \
   java/kotlin/pom.xml                                                              \
   java/kotlin/pom_template.xml                                                     \
+  java/kotlin/src/main/kotlin/com/google/protobuf/Anies.kt                         \
   java/kotlin/src/main/kotlin/com/google/protobuf/ByteStrings.kt                   \
   java/kotlin/src/main/kotlin/com/google/protobuf/DslList.kt                       \
   java/kotlin/src/main/kotlin/com/google/protobuf/DslMap.kt                        \
@@ -553,6 +554,7 @@ java_EXTRA_DIST=
   java/kotlin/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt\
   java/kotlin/src/main/kotlin/com/google/protobuf/ProtoDslMarker.kt                \
   java/kotlin/src/main/kotlin/com/google/protobuf/UnmodifiableCollections.kt       \
+  java/kotlin/src/test/kotlin/com/google/protobuf/AniesTest.kt                     \
   java/kotlin/src/test/kotlin/com/google/protobuf/ByteStringsTest.kt               \
   java/kotlin/src/test/kotlin/com/google/protobuf/DslListTest.kt                   \
   java/kotlin/src/test/kotlin/com/google/protobuf/DslMapTest.kt                    \

cmake/CMakeLists.txt

@@ -297,6 +297,7 @@ if (protobuf_BUILD_TESTS OR protobuf_BUILD_CONFORMANCE OR protobuf_BUILD_EXAMPLE
 endif ()
 
 if (protobuf_BUILD_TESTS)
+  enable_testing()
   include(tests.cmake)
 endif (protobuf_BUILD_TESTS)
 

cmake/README.md

@@ -36,6 +36,10 @@ If *git* command is not available from *Command Prompt*, add it to system *PATH*
 
     C:\Path\to>set PATH=%PATH%;C:\Program Files\Git\cmd
 
+Optionally, you will want to download [ninja](https://ninja-build.org/) and add it to your *PATH* variable.
+
+    C:\Path\to>set PATH=%PATH%;C:\tools\ninja
+
 Good. Now you are ready to continue.
 
 Getting Sources
@@ -52,29 +56,25 @@ download `protobuf-all-[VERSION].tar.gz`.
 
 Or you can use git to clone from protobuf git repository.
 
-     C:\Path\to> git clone -b [release_tag] https://github.com/protocolbuffers/protobuf.git
+     C:\Path\to> mkdir src & cd src
+     C:\Path\to\src> git clone -b [release_tag] https://github.com/protocolbuffers/protobuf.git
 
 Where *[release_tag]* is a git tag like *v3.0.0-beta-1* or a branch name like *master*
 if you want to get the latest code.
 
 Go to the project folder:
 
-     C:\Path\to>cd protobuf
-     C:\Path\to\protobuf>
+     C:\Path\to\src> cd protobuf
+     C:\Path\to\src\protobuf>
 
 Remember to update any submodules if you are using git clone (you can skip this
 step if you are using a release .tar.gz or .zip package):
 
 ```console
-C:\Path\to> git submodule update --init --recursive
+C:\Path\to\src\protobuf> git submodule update --init --recursive
 ```
 
-Now go to *cmake* folder in protobuf sources:
-
-     C:\Path\to\protobuf>cd cmake
-     C:\Path\to\protobuf\cmake>
-
-Good. Now you are ready to *CMake* configuration.
+Good. Now you are ready for *CMake* configuration.
 
 CMake Configuration
 ===================
@@ -82,71 +82,119 @@ CMake Configuration
 *CMake* supports a lot of different
 [generators](http://www.cmake.org/cmake/help/latest/manual/cmake-generators.7.html)
 for various native build systems.
-We are only interested in
-[Makefile](http://www.cmake.org/cmake/help/latest/manual/cmake-generators.7.html#makefile-generators)
-and
-[Visual Studio](http://www.cmake.org/cmake/help/latest/manual/cmake-generators.7.html#visual-studio-generators)
-generators.
 
-We will use shadow building to separate the temporary files from the protobuf source code.
+Of most interest to Windows programmers are the following:
+
+* [Makefile](http://www.cmake.org/cmake/help/latest/manual/cmake-generators.7.html#makefile-generators).
+  This generates NMake Makefiles for Visual Studio. These work, but they are rather slow.
+
+* [Visual Studio](http://www.cmake.org/cmake/help/latest/manual/cmake-generators.7.html#visual-studio-generators)
+  This generates a Visual Studio solution for the project.
+
+* [Ninja](https://cmake.org/cmake/help/latest/manual/cmake-generators.7.html#ninja-generator)
+  This uses the external tool [Ninja](https://ninja-build.org/) to build. It is the fastest solution available.
+  
+Note that as of Visual Studio 2015, Visual Studio includes
+[support for opening directly CMake-based projects](https://docs.microsoft.com/en-us/cpp/build/cmake-projects-in-visual-studio).
+
+It is considered good practice not to build CMake projects in the source tree but in a separate folder.
 
 Create a temporary *build* folder and change your working directory to it:
 
-     C:\Path\to\protobuf\cmake>mkdir build & cd build
-     C:\Path\to\protobuf\cmake\build>
+     mkdir C:\Path\to\build\protobuf
+     cd C:\Path\to\build\protobuf
+     C:\Path\to\build\protobuf>
 
-The *Makefile* generator can build the project in only one configuration, so you need to build
+The *Makefile* and *Ninja* generators can build the project in only one configuration, so you need to build
 a separate folder for each configuration.
 
-To start using a *Release* configuration:
+To start using a *Release* configuration via the *NMmake* generator:
 
-     C:\Path\to\protobuf\cmake\build>mkdir release & cd release
-     C:\Path\to\protobuf\cmake\build\release>cmake -G "NMake Makefiles" ^
+     C:\Path\to\build\protobuf>mkdir release & cd release
+     C:\Path\to\build\protobuf\release>cmake -G "NMake Makefiles" ^
      -DCMAKE_BUILD_TYPE=Release ^
-     -DCMAKE_INSTALL_PREFIX=../../../../install ^
-     ../..
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install ^
+     C:\Path\to\src\protobuf
 
-It will generate *nmake* *Makefile* in current directory.
+It will generate a *NMake* *Makefile* in the current directory.
 
-To use *Debug* configuration:
+To use *Debug* configuration using *Ninja*:
 
-     C:\Path\to\protobuf\cmake\build>mkdir debug & cd debug
-     C:\Path\to\protobuf\cmake\build\debug>cmake -G "NMake Makefiles" ^
+     C:\Path\to\build\protobuf>mkdir debug & cd debug
+     C:\Path\to\build\protobuf\debug>cmake -G "Ninja" ^
      -DCMAKE_BUILD_TYPE=Debug ^
-     -DCMAKE_INSTALL_PREFIX=../../../../install ^
-     ../..
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install ^
+     C:\Path\to\src\protobuf
 
-It will generate *nmake* *Makefile* in current directory.
+It will generate *Ninja* build scripts in current directory.
 
-To create *Visual Studio* solution file:
+The *Visual Studio* generator is multi-configuration: it will generate a single *.sln* file that can be used for both *Debug* and *Release*:
 
-     C:\Path\to\protobuf\cmake\build>mkdir solution & cd solution
-     C:\Path\to\protobuf\cmake\build\solution>cmake -G "Visual Studio 16 2019" ^
-     -DCMAKE_INSTALL_PREFIX=../../../../install ^
-     ../..
+     C:\Path\to\build\protobuf>mkdir solution & cd solution
+     C:\Path\to\build\protobuf\solution>cmake -G "Visual Studio 16 2019" ^
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install ^
+     C:\Path\to\src\protobuf
 
 It will generate *Visual Studio* solution file *protobuf.sln* in current directory.
 
-If the *gmock* directory does not exist, and you do not want to build protobuf unit tests,
-you need to add *cmake* command argument `-Dprotobuf_BUILD_TESTS=OFF` to disable testing.
+Unit Tests
+----------
+
+Unit tests are being built along with the rest of protobuf. The unit tests require Google Mock (now a part of Google Test).
+
+A copy of [Google Test](https://github.com/google/googletest) is included as a Git submodule in the `third-party/googletest` folder.
+(You do need to initialize the Git submodules as explained above.)
+
+Alternately, you may want to use protobuf in a larger set-up, you may want to use that standard CMake approach where
+you build and install a shared copy of Google Test.
+
+After you've built and installed your Google Test copy, you need add the following definition to your *cmake* command line
+during the configuration step: `-Dprotobuf_USE_EXTERNAL_GTEST=ON`.
+This will cause the standard CMake `find_package(GTest REQUIRED)` to be used.
 
-To make a *Visual Studio* file for Visual Studio 16 2019, create the *Visual Studio*
-solution file above and edit the CMakeCache file.
+[find_package](https://cmake.org/cmake/help/latest/command/find_package.html) will search in a default location,
+which on Windows is *C:\Program Files*. This is most likely not what you want. You will want instead to search for
+Google Test in your project's root directory (i.e. the same directory you've passed to `CMAKE_INSTALL_PREFIX` when
+building Google Test). For this, you need to set the `CMAKE_PREFIX_PATH` CMake variable. (There are other ways in CMake,
+see the [manual](https://cmake.org/cmake/help/latest/command/find_package.html) for details.)
 
-	C:Path\to\protobuf\cmake\build\solution\CMakeCache
+For example:
 
-Then create the *Visual Studio* solution file again
+     C:\Path\to\build\protobuf>mkdir solution & cd solution
+     C:\Path\to\build\protobuf\solution>cmake -G "Visual Studio 16 2019" ^
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install ^
+     -DCMAKE_PREFIX_PATH=C:\Path\to\my_big_project ^
+     -Dprotobuf_USE_EXTERNAL_GTEST=ON ^
+     C:\Path\to\src\protobuf
+
+In most cases, `CMAKE_PREFIX_PATH` and `CMAKE_INSTALL_PREFIX` will point to the same directory.
+
+To disable testing completely, you need to add the following argument to you *cmake* command line: `-Dprotobuf_BUILD_TESTS=OFF`.
+
+For example:
+
+     C:\Path\to\build\protobuf\solution>cmake -G "Visual Studio 16 2019" ^
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install ^
+     -Dprotobuf_BUILD_TESTS=OFF ^
+     C:\Path\to\src\protobuf
 
 Compiling
 =========
 
-To compile protobuf:
+The standard way to compile a *CMake* project is `cmake --build <directory>`.
+
+
+Note that if your generator supports multiple configurations, you will probably want to specify which one to build:
 
-     C:\Path\to\protobuf\cmake\build\release>nmake
+     cmake --build C:\Path\to\build\protobuf\solution --config Release
+
+You can also run directly the build tool you've configured:
+
+     C:\Path\to\build\protobuf\release>nmake
 
 or
 
-     C:\Path\to\protobuf\cmake\build\debug>nmake
+     C:\Path\to\build\protobuf\debug>ninja
 
 And wait for the compilation to finish.
 
@@ -164,11 +212,15 @@ Testing
 To run unit-tests, first you must compile protobuf as described above.
 Then run:
 
-     C:\Path\to\protobuf\cmake\build\release>nmake check
+     C:\Path\to\protobuf\cmake\build\release>ctest --progress --output-on-failure
+
+You can also build the `check` target (not idiomatic CMake usage, though):
+
+     C:\Path\to\protobuf\cmake\build\release>cmake --build . --target check
 
 or
 
-     C:\Path\to\protobuf\cmake\build\debug>nmake check
+    C:\Path\to\build\protobuf\release>ninja check
 
 You can also build project *check* from Visual Studio solution.
 Yes, it may sound strange, but it works.
@@ -183,9 +235,9 @@ You should see output similar to:
      [==========] 1546 tests from 165 test cases ran. (2529 ms total)
      [  PASSED  ] 1546 tests.
 
-To run specific tests:
+To run specific tests, you need to pass some command line arguments to the test program itself:
 
-     C:\Path\to\protobuf>cmake\build\release\tests.exe --gtest_filter=AnyTest*
+     C:\Path\to\build\protobuf\release>tests.exe --gtest_filter=AnyTest*
      Running main() from gmock_main.cc
      Note: Google Test filter = AnyTest*
      [==========] Running 3 tests from 1 test case.
@@ -210,13 +262,17 @@ If all tests are passed, safely continue.
 Installing
 ==========
 
-To install protobuf to the specified *install* folder:
+To install protobuf to the *install* folder you've specified in the configuration step, you need to build the `install` target:
+
+     cmake --build C:\Path\to\build\protobuf\solution --config Release --target install
+
+Or if you prefer:
 
-     C:\Path\to\protobuf\cmake\build\release>nmake install
+     C:\Path\to\build\protobuf\release>nmake install
 
 or
 
-     C:\Path\to\protobuf\cmake\build\debug>nmake install
+     C:\Path\to\build\protobuf\debug>ninja install
 
 You can also build project *INSTALL* from Visual Studio solution.
 It sounds not so strange and it works.
@@ -280,16 +336,16 @@ You can also compile it from source by yourself.
 
 Getting sources:
 
-     C:\Path\to>git clone -b v1.2.8 https://github.com/madler/zlib.git
-     C:\Path\to>cd zlib
+     C:\Path\to\src>git clone -b v1.2.8 https://github.com/madler/zlib.git
+     C:\Path\to\src>cd zlib
 
 Compiling and Installing:
 
-     C:\Path\to\zlib>mkdir build & cd build
-     C:\Path\to\zlib\build>mkdir release & cd release
-     C:\Path\to\zlib\build\release>cmake -G "NMake Makefiles" -DCMAKE_BUILD_TYPE=Release ^
-     -DCMAKE_INSTALL_PREFIX=../../../install ../..
-     C:\Path\to\zlib\build\release>nmake & nmake install
+     C:\Path\to\src\zlib>mkdir C:\Path\to\build\zlib & cd C:\Path\to\build\zlib
+     C:\Path\to\build\zlib>mkdir release & cd release
+     C:\Path\to\build\zlib\release>cmake -G "Ninja" -DCMAKE_BUILD_TYPE=Release ^
+     -DCMAKE_INSTALL_PREFIX=C:\Path\to\install C:\Path\to\src\zlib
+     C:\Path\to\src\zlib\build\release>cmake --build . --target install
 
 You can make *debug* version or use *Visual Studio* generator also as before for the
 protobuf project.

cmake/libprotobuf-lite.cmake

@@ -101,7 +101,7 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Android")
 	target_link_libraries(libprotobuf-lite log)
 endif()
 target_include_directories(libprotobuf-lite PUBLIC ${protobuf_source_dir}/src)
-if(MSVC AND protobuf_BUILD_SHARED_LIBS)
+if(protobuf_BUILD_SHARED_LIBS)
   target_compile_definitions(libprotobuf-lite
     PUBLIC  PROTOBUF_USE_DLLS
     PRIVATE LIBPROTOBUF_EXPORTS)

cmake/libprotobuf.cmake

@@ -118,7 +118,7 @@ if(${CMAKE_SYSTEM_NAME} STREQUAL "Android")
 	target_link_libraries(libprotobuf log)
 endif()
 target_include_directories(libprotobuf PUBLIC ${protobuf_source_dir}/src)
-if(MSVC AND protobuf_BUILD_SHARED_LIBS)
+if(protobuf_BUILD_SHARED_LIBS)
   target_compile_definitions(libprotobuf
     PUBLIC  PROTOBUF_USE_DLLS
     PRIVATE LIBPROTOBUF_EXPORTS)

cmake/protobuf-config.cmake.in

@@ -11,7 +11,7 @@ function(protobuf_generate)
   include(CMakeParseArguments)
 
   set(_options APPEND_PATH)
-  set(_singleargs LANGUAGE OUT_VAR EXPORT_MACRO PROTOC_OUT_DIR PLUGIN)
+  set(_singleargs LANGUAGE OUT_VAR EXPORT_MACRO PROTOC_OUT_DIR PLUGIN PLUGIN_OPTIONS)
   if(COMMAND target_sources)
     list(APPEND _singleargs TARGET)
   endif()
@@ -39,9 +39,18 @@ function(protobuf_generate)
   endif()
 
   if(protobuf_generate_EXPORT_MACRO AND protobuf_generate_LANGUAGE STREQUAL cpp)
-    set(_dll_export_decl "dllexport_decl=${protobuf_generate_EXPORT_MACRO}:")
+    set(_dll_export_decl "dllexport_decl=${protobuf_generate_EXPORT_MACRO}")
   endif()
 
+  foreach(_option ${_dll_export_decl} ${protobuf_generate_PLUGIN_OPTIONS})
+    # append comma - not using CMake lists and string replacement as users
+    # might have semicolons in options
+    if(_plugin_options)
+      set( _plugin_options "${_plugin_options},")
+    endif()
+    set(_plugin_options "${_plugin_options}${_option}")
+  endforeach()
+
   if(protobuf_generate_PLUGIN)
       set(_plugin "--plugin=${protobuf_generate_PLUGIN}")
   endif()
@@ -127,12 +136,20 @@ function(protobuf_generate)
     endforeach()
     list(APPEND _generated_srcs_all ${_generated_srcs})
 
+    set(_comment "Running ${protobuf_generate_LANGUAGE} protocol buffer compiler on ${_proto}")
+    if(protobuf_generate_PROTOC_OPTIONS)
+      set(_comment "${_comment}, protoc-options: ${protobuf_generate_PROTOC_OPTIONS}")
+    endif()
+    if(_plugin_options)
+      set(_comment "${_comment}, plugin-options: ${_plugin_options}")
+    endif()
+
     add_custom_command(
       OUTPUT ${_generated_srcs}
       COMMAND protobuf::protoc
-      ARGS ${protobuf_generate_PROTOC_OPTIONS} --${protobuf_generate_LANGUAGE}_out ${_dll_export_decl}${protobuf_generate_PROTOC_OUT_DIR} ${_plugin} ${_protobuf_include_path} ${_abs_file}
+      ARGS ${protobuf_generate_PROTOC_OPTIONS} --${protobuf_generate_LANGUAGE}_out ${_plugin_options}:${protobuf_generate_PROTOC_OUT_DIR} ${_plugin} ${_protobuf_include_path} ${_abs_file}
       DEPENDS ${_abs_file} protobuf::protoc
-      COMMENT "Running ${protobuf_generate_LANGUAGE} protocol buffer compiler on ${_proto}. Custom options: ${protobuf_generate_PROTOC_OPTIONS}"
+      COMMENT ${_comment}
       VERBATIM )
   endforeach()
 

cmake/protobuf-module.cmake.in

@@ -94,7 +94,7 @@ function(_protobuf_find_libraries name filename)
   elseif(${name}_LIBRARY)
     # Honor cache entry used by CMake 3.5 and lower.
     set(${name}_LIBRARIES "${${name}_LIBRARY}" PARENT_SCOPE)
-  else()
+  elseif(TARGET protobuf::lib${filename})
     get_target_property(${name}_LIBRARY_RELEASE protobuf::lib${filename}
       LOCATION_RELEASE)
     get_target_property(${name}_LIBRARY_RELWITHDEBINFO protobuf::lib${filename}
@@ -134,6 +134,7 @@ get_target_property(Protobuf_INCLUDE_DIRS protobuf::libprotobuf
   INTERFACE_INCLUDE_DIRECTORIES)
 
 # Set the protoc Executable
+if(NOT Protobuf_PROTOC_EXECUTABLE AND TARGET protobuf::protoc)
   get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc
     IMPORTED_LOCATION_RELEASE)
   if(NOT EXISTS "${Protobuf_PROTOC_EXECUTABLE}")
@@ -152,6 +153,7 @@ if(NOT EXISTS "${Protobuf_PROTOC_EXECUTABLE}")
     get_target_property(Protobuf_PROTOC_EXECUTABLE protobuf::protoc
       IMPORTED_LOCATION_NOCONFIG)
   endif()
+endif()
 
 # Version info variable
 set(Protobuf_VERSION "@protobuf_VERSION@")

cmake/tests.cmake

@@ -1,3 +1,12 @@
+option(protobuf_USE_EXTERNAL_GTEST "Use external Google Test (i.e. not the one in third_party/googletest)" OFF)
+
+option(protobuf_ABSOLUTE_TEST_PLUGIN_PATH
+  "Using absolute test_plugin path in tests" ON)
+mark_as_advanced(protobuf_ABSOLUTE_TEST_PLUGIN_PATH)
+
+if (protobuf_USE_EXTERNAL_GTEST)
+  find_package(GTest REQUIRED)
+else()
   if (NOT EXISTS "${PROJECT_SOURCE_DIR}/../third_party/googletest/CMakeLists.txt")
     message(FATAL_ERROR
             "Cannot find third_party/googletest directory that's needed to "
@@ -7,10 +16,6 @@ if (NOT EXISTS "${PROJECT_SOURCE_DIR}/../third_party/googletest/CMakeLists.txt")
             "  cmake -Dprotobuf_BUILD_TESTS=OFF\n")
   endif()
 
-option(protobuf_ABSOLUTE_TEST_PLUGIN_PATH
-  "Using absolute test_plugin path in tests" ON)
-mark_as_advanced(protobuf_ABSOLUTE_TEST_PLUGIN_PATH)
-
   set(googlemock_source_dir "${protobuf_source_dir}/third_party/googletest/googlemock")
   set(googletest_source_dir "${protobuf_source_dir}/third_party/googletest/googletest")
   include_directories(
@@ -28,6 +33,11 @@ target_link_libraries(gmock ${CMAKE_THREAD_LIBS_INIT})
   add_library(gmock_main STATIC "${googlemock_source_dir}/src/gmock_main.cc")
   target_link_libraries(gmock_main gmock)
 
+  add_library(GTest::gmock ALIAS gmock)
+  add_library(GTest::gmock_main ALIAS gmock_main)
+endif()
+
+
 set(lite_test_protos
   google/protobuf/map_lite_unittest.proto
   google/protobuf/unittest_import_lite.proto
@@ -229,7 +239,7 @@ if (MSVC)
     /wd4146 # unary minus operator applied to unsigned type, result still unsigned
   )
 endif()
-target_link_libraries(tests libprotoc libprotobuf gmock_main)
+target_link_libraries(tests libprotoc libprotobuf GTest::gmock_main)
 
 set(test_plugin_files
   ${protobuf_source_dir}/src/google/protobuf/compiler/mock_code_generator.cc
@@ -239,21 +249,25 @@ set(test_plugin_files
 )
 
 add_executable(test_plugin ${test_plugin_files})
-target_link_libraries(test_plugin libprotoc libprotobuf gmock)
+target_link_libraries(test_plugin libprotoc libprotobuf GTest::gmock)
 
 set(lite_test_files
   ${protobuf_source_dir}/src/google/protobuf/lite_unittest.cc
 )
 add_executable(lite-test ${lite_test_files} ${common_lite_test_files} ${lite_test_proto_files})
-target_link_libraries(lite-test libprotobuf-lite gmock_main)
+target_link_libraries(lite-test libprotobuf-lite GTest::gmock_main)
 
 set(lite_arena_test_files
   ${protobuf_source_dir}/src/google/protobuf/lite_arena_unittest.cc
 )
 add_executable(lite-arena-test ${lite_arena_test_files} ${common_lite_test_files} ${lite_test_proto_files})
-target_link_libraries(lite-arena-test libprotobuf-lite gmock_main)
+target_link_libraries(lite-arena-test libprotobuf-lite GTest::gmock_main)
 
 add_custom_target(check
   COMMAND tests
   DEPENDS tests test_plugin
   WORKING_DIRECTORY ${protobuf_source_dir})
+
+add_test(NAME check
+  COMMAND tests
+  WORKING_DIRECTORY "${protobuf_source_dir}")

conformance/conformance_nodejs.js

@@ -41,11 +41,16 @@ function doTest(request) {
   var response = new conformance.ConformanceResponse();
 
   try {
-    if (request.getRequestedOutputFormat() === conformance.WireFormat.JSON) {
+    if (request.getRequestedOutputFormat() == conformance.WireFormat.JSON) {
       response.setSkipped("JSON not supported.");
       return response;
     }
 
+    if (request.getRequestedOutputFormat() == conformance.WireFormat.TEXT_FORMAT) {
+      response.setSkipped('Text format is not supported as output format.');
+      return response;
+    }
+
     switch (request.getPayloadCase()) {
       case conformance.ConformanceRequest.PayloadCase.PROTOBUF_PAYLOAD: {
         if (request.getMessageType() == "protobuf_test_messages.proto3.TestAllTypesProto3") {
@@ -67,7 +72,7 @@ function doTest(request) {
         } else {
           throw "Protobuf request doesn\'t have specific payload type";
         }
-      }
+      } break;
 
       case conformance.ConformanceRequest.PayloadCase.JSON_PAYLOAD:
         response.setSkipped("JSON not supported.");

conformance/conformance_test.cc

@@ -350,7 +350,17 @@ bool ConformanceTestSuite::CheckSetEmpty(
     StringAppendF(&output_, "\n");
 
     if (!write_to_file.empty()) {
-      std::ofstream os(write_to_file);
+      std::string full_filename;
+      const std::string* filename = &write_to_file;
+      if (!output_dir_.empty()) {
+        full_filename = output_dir_;
+        if (*output_dir_.rbegin() != '/') {
+          full_filename.push_back('/');
+        }
+        full_filename += write_to_file;
+        filename = &full_filename;
+      }
+      std::ofstream os(*filename);
       if (os) {
         for (std::set<string>::const_iterator iter = set_to_check.begin();
              iter != set_to_check.end(); ++iter) {
@@ -358,7 +368,7 @@ bool ConformanceTestSuite::CheckSetEmpty(
         }
       } else {
         StringAppendF(&output_, "Failed to open file: %s\n",
-                      write_to_file.c_str());
+                      filename->c_str());
       }
     }
 

conformance/conformance_test.h

@@ -174,6 +174,11 @@ class ConformanceTestSuite {
     failure_list_flag_name_ = failure_list_flag_name;
   }
 
+  // Sets the path of the output directory.
+  void SetOutputDir(const char* output_dir) {
+    output_dir_ = output_dir;
+  }
+
   // Run all the conformance tests against the given test runner.
   // Test output will be stored in "output".
   //
@@ -296,6 +301,7 @@ class ConformanceTestSuite {
   bool verbose_;
   bool enforce_recommended_;
   std::string output_;
+  std::string output_dir_;
   std::string failure_list_flag_name_;
   std::string failure_list_filename_;
 

conformance/conformance_test_runner.cc

@@ -141,6 +141,9 @@ void UsageError() {
           "                              strictly conforming to protobuf\n");
   fprintf(stderr,
           "                              spec.\n");
+  fprintf(stderr,
+          "  --output_dir                <dirname> Directory to write\n"
+          "                              output files.\n");
   exit(1);
 }
 
@@ -208,6 +211,9 @@ int ForkPipeRunner::Run(
         suite->SetVerbose(true);
       } else if (strcmp(argv[arg], "--enforce_recommended") == 0) {
         suite->SetEnforceRecommended(true);
+      } else if (strcmp(argv[arg], "--output_dir") == 0) {
+        if (++arg == argc) UsageError();
+        suite->SetOutputDir(argv[arg]);
       } else if (argv[arg][0] == '-') {
         bool recognized_flag = false;
         for (ConformanceTestSuite* suite : suites) {

conformance/failure_list_js.txt

@@ -0,0 +1,162 @@
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.ENUM[4].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.ENUM[5].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.FIXED64[2].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.INT32[7].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.INT64[2].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.SFIXED64[2].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.SINT64[2].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.UINT32[8].ProtobufOutput
+Recommended.Proto2.ProtobufInput.ValidDataScalarBinary.UINT64[2].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.DefaultOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.PackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.UnpackedOutput.ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.ENUM[4].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.ENUM[5].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.FIXED64[2].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.INT32[7].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.INT64[2].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SFIXED64[2].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.SINT64[2].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.UINT32[8].ProtobufOutput
+Recommended.Proto3.ProtobufInput.ValidDataScalarBinary.UINT64[2].ProtobufOutput
+Required.Proto2.ProtobufInput.RepeatedScalarSelectsLast.ENUM.ProtobufOutput
+Required.Proto2.ProtobufInput.RepeatedScalarSelectsLast.FIXED64.ProtobufOutput
+Required.Proto2.ProtobufInput.RepeatedScalarSelectsLast.UINT64.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.INT32.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.INT64.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.ENUM[4].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.ENUM[5].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.FIXED64[2].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.INT32[7].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.INT64[2].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.SFIXED64[2].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.SINT64[2].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.UINT32[8].ProtobufOutput
+Required.Proto2.ProtobufInput.ValidDataScalar.UINT64[2].ProtobufOutput
+Required.Proto3.ProtobufInput.RepeatedScalarSelectsLast.ENUM.ProtobufOutput
+Required.Proto3.ProtobufInput.RepeatedScalarSelectsLast.FIXED64.ProtobufOutput
+Required.Proto3.ProtobufInput.RepeatedScalarSelectsLast.UINT64.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.ENUM.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.FIXED64.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.INT32.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.INT32.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.INT64.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.INT64.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.SFIXED64.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.SINT64.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.SINT64.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.UINT32.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.UINT32.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.UINT64.PackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataRepeated.UINT64.UnpackedInput.ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.ENUM[4].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.ENUM[5].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.FIXED64[2].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.INT32[7].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.INT64[2].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.SFIXED64[2].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.SINT64[2].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.UINT32[8].ProtobufOutput
+Required.Proto3.ProtobufInput.ValidDataScalar.UINT64[2].ProtobufOutput

csharp/src/Google.Protobuf.Test/UnknownFieldSetTest.cs

@@ -138,6 +138,29 @@ namespace Google.Protobuf
             Assert.AreEqual(message.ToByteArray(), otherEmptyMessage.ToByteArray());
         }
 
+        [Test]
+        public void TestClone_LengthDelimited()
+        {
+            var unknownVarintField = new UnknownField();
+            unknownVarintField.AddVarint(99);
+
+            var unknownLengthDelimitedField1 = new UnknownField();
+            unknownLengthDelimitedField1.AddLengthDelimited(ByteString.CopyFromUtf8("some data"));
+
+            var unknownLengthDelimitedField2 = new UnknownField();
+            unknownLengthDelimitedField2.AddLengthDelimited(ByteString.CopyFromUtf8("some more data"));
+
+            var destUnknownFieldSet = new UnknownFieldSet();
+            destUnknownFieldSet.AddOrReplaceField(997, unknownVarintField);
+            destUnknownFieldSet.AddOrReplaceField(999, unknownLengthDelimitedField1);
+            destUnknownFieldSet.AddOrReplaceField(999, unknownLengthDelimitedField2);
+
+            var clone = UnknownFieldSet.Clone(destUnknownFieldSet);
+
+            Assert.IsTrue(clone.HasField(997));
+            Assert.IsTrue(clone.HasField(999));
+        }
+
         [Test]
         [TestCaseSource(typeof(Data), "Messages")]
         public void TestDiscardUnknownFields(IMessage message)

java/core/src/main/java/com/google/protobuf/ArrayDecoders.java

@@ -45,14 +45,15 @@ import java.io.IOException;
  */
 @CheckReturnValue
 final class ArrayDecoders {
+
+  private ArrayDecoders() {
+  }
+
   /**
    * A helper used to return multiple values in a Java function. Java doesn't natively support
    * returning multiple values in a function. Creating a new Object to hold the return values will
    * be too expensive. Instead, we pass a Registers instance to functions that want to return
    * multiple values and let the function set the return value in this Registers instance instead.
-   *
-   * <p>TODO(xiaofeng): This could be merged into CodedInputStream or CodedInputStreamReader which
-   * is already being passed through all the parsing routines.
    */
   static final class Registers {
     public int int1;

java/core/src/main/java/com/google/protobuf/ByteString.java

@@ -316,13 +316,8 @@ public abstract class ByteString implements Iterable<Byte>, Serializable {
       };
 
   /**
-<<<<<<< HEAD
-   * Returns a {@link Comparator} which compares {@link ByteString}-s lexicographically
-   * as sequences of unsigned byte values between 0 and 255, inclusive.
-=======
    * Returns a {@link Comparator} which compares {@link ByteString}-s lexicographically as sequences
    * of unsigned bytes (i.e. values between 0 and 255, inclusive).
->>>>>>> refs/tags/sync-piper
    *
    * <p>For example, {@code (byte) -1} is considered to be greater than {@code (byte) 1} because it
    * is interpreted as an unsigned value, {@code 255}:

java/core/src/main/java/com/google/protobuf/DescriptorMessageInfoFactory.java

@@ -61,8 +61,31 @@ import java.util.concurrent.ConcurrentHashMap;
 final class DescriptorMessageInfoFactory implements MessageInfoFactory {
   private static final String GET_DEFAULT_INSTANCE_METHOD_NAME = "getDefaultInstance";
   private static final DescriptorMessageInfoFactory instance = new DescriptorMessageInfoFactory();
+
+  /**
+   * Names that should be avoided (in UpperCamelCase format).
+   * Using them causes the compiler to generate accessors whose names
+   * collide with methods defined in base classes.
+   *
+   * Keep this list in sync with kForbiddenWordList in
+   * src/google/protobuf/compiler/java/java_helpers.cc
+   */
   private static final Set<String> specialFieldNames =
-      new HashSet<>(Arrays.asList("cached_size", "serialized_size", "class"));
+      new HashSet<>(Arrays.asList(
+        // java.lang.Object:
+        "Class",
+        // com.google.protobuf.MessageLiteOrBuilder:
+        "DefaultInstanceForType",
+        // com.google.protobuf.MessageLite:
+        "ParserForType",
+        "SerializedSize",
+        // com.google.protobuf.MessageOrBuilder:
+        "AllFields",
+        "DescriptorForType",
+        "InitializationErrorString",
+        "UnknownFields",
+        // obsolete. kept for backwards compatibility of generated code
+        "CachedSize"));
 
   // Disallow construction - it's a singleton.
   private DescriptorMessageInfoFactory() {}
@@ -593,21 +616,101 @@ final class DescriptorMessageInfoFactory implements MessageInfoFactory {
     String name = (fd.getType() == FieldDescriptor.Type.GROUP)
                   ? fd.getMessageType().getName()
                   : fd.getName();
-    String suffix = specialFieldNames.contains(name) ? "__" : "_";
-    return snakeCaseToCamelCase(name) + suffix;
+
+    // convert to UpperCamelCase for comparison to the specialFieldNames
+    // (which are in UpperCamelCase)
+    String upperCamelCaseName = snakeCaseToUpperCamelCase(name);
+
+    // Append underscores to match the behavior of the protoc java compiler
+    final String suffix;
+    if (specialFieldNames.contains(upperCamelCaseName)) {
+      // For proto field names that match the specialFieldNames,
+      // the protoc java compiler appends "__" to the java field name
+      // to prevent the field's accessor method names from clashing with other methods.
+      // For example:
+      //     proto field name = "class"
+      //     java field name = "class__"
+      //     accessor method name = "getClass_()"  (so that it does not clash with Object.getClass())
+      suffix = "__";
+    } else {
+      // For other proto field names,
+      // the protoc java compiler appends "_" to the java field name
+      // to prevent field names from clashing with java keywords.
+      // For example:
+      //     proto field name = "int"
+      //     java field name = "int_" (so that it does not clash with int keyword)
+      //     accessor method name = "getInt()"
+      suffix = "_";
+    }
+    return snakeCaseToLowerCamelCase(name) + suffix;
   }
 
   private static String getCachedSizeFieldName(FieldDescriptor fd) {
-    return snakeCaseToCamelCase(fd.getName()) + "MemoizedSerializedSize";
+    return snakeCaseToLowerCamelCase(fd.getName()) + "MemoizedSerializedSize";
   }
 
   /**
-   * This method must match exactly with the corresponding function in protocol compiler. See:
-   * https://github.com/google/protobuf/blob/v3.0.0/src/google/protobuf/compiler/java/java_helpers.cc#L153
+   * Converts a snake case string into lower camel case.
+   *
+   * <p>Some examples:</p>
+   * <pre>
+   *     snakeCaseToLowerCamelCase("foo_bar") => "fooBar"
+   *     snakeCaseToLowerCamelCase("foo") => "foo"
+   * </pre>
+   *
+   * @param snakeCase the string in snake case to convert
+   * @return the string converted to camel case, with a lowercase first character
+   */
+  private static String snakeCaseToLowerCamelCase(String snakeCase) {
+    return snakeCaseToCamelCase(snakeCase, false);
+  }
+
+  /**
+   * Converts a snake case string into upper camel case.
+   *
+   * <p>Some examples:</p>
+   * <pre>
+   *     snakeCaseToUpperCamelCase("foo_bar") => "FooBar"
+   *     snakeCaseToUpperCamelCase("foo") => "Foo"
+   * </pre>
+   *
+   * @param snakeCase the string in snake case to convert
+   * @return the string converted to camel case, with an uppercase first character
+   */
+  private static String snakeCaseToUpperCamelCase(String snakeCase) {
+    return snakeCaseToCamelCase(snakeCase, true);
+  }
+
+  /**
+   * Converts a snake case string into camel case.
+   *
+   * <p>For better readability, prefer calling either
+   * {@link #snakeCaseToLowerCamelCase(String)} or {@link #snakeCaseToUpperCamelCase(String)}.</p>
+   *
+   * <p>Some examples:</p>
+   * <pre>
+   *     snakeCaseToCamelCase("foo_bar", false) => "fooBar"
+   *     snakeCaseToCamelCase("foo_bar", true) => "FooBar"
+   *     snakeCaseToCamelCase("foo", false) => "foo"
+   *     snakeCaseToCamelCase("foo", true) => "Foo"
+   *     snakeCaseToCamelCase("Foo", false) => "foo"
+   *     snakeCaseToCamelCase("fooBar", false) => "fooBar"
+   * </pre>
+   *
+   * <p>This implementation of this method must exactly match the corresponding
+   * function in the protocol compiler.  Specifically, the
+   * {@code UnderscoresToCamelCase} function in
+   * {@code src/google/protobuf/compiler/java/java_helpers.cc}.</p>
+   *
+   * @param snakeCase the string in snake case to convert
+   * @param capFirst true if the first letter of the returned string should be uppercase.
+   *                 false if the first letter of the returned string should be lowercase.
+   * @return the string converted to camel case, with an uppercase or lowercase first
+   *         character depending on if {@code capFirst} is true or false, respectively
    */
-  private static String snakeCaseToCamelCase(String snakeCase) {
+  private static String snakeCaseToCamelCase(String snakeCase, boolean capFirst) {
     StringBuilder sb = new StringBuilder(snakeCase.length() + 1);
-    boolean capNext = false;
+    boolean capNext = capFirst;
     for (int ctr = 0; ctr < snakeCase.length(); ctr++) {
       char next = snakeCase.charAt(ctr);
       if (next == '_') {
@@ -653,7 +756,7 @@ final class DescriptorMessageInfoFactory implements MessageInfoFactory {
 
   /** Constructs the name of the get method for the given field in the proto. */
   private static String getterForField(String snakeCase) {
-    String camelCase = snakeCaseToCamelCase(snakeCase);
+    String camelCase = snakeCaseToLowerCamelCase(snakeCase);
     StringBuilder builder = new StringBuilder("get");
     // Capitalize the first character in the field name.
     builder.append(Character.toUpperCase(camelCase.charAt(0)));
@@ -679,7 +782,7 @@ final class DescriptorMessageInfoFactory implements MessageInfoFactory {
     }
 
     private static OneofInfo newInfo(Class<?> messageType, OneofDescriptor desc) {
-      String camelCase = snakeCaseToCamelCase(desc.getName());
+      String camelCase = snakeCaseToLowerCamelCase(desc.getName());
       String valueFieldName = camelCase + "_";
       String caseFieldName = camelCase + "Case_";
 

java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java

@@ -692,7 +692,7 @@ public abstract class GeneratedMessageLite<
       // The wire format for MessageSet is:
       //   message MessageSet {
       //     repeated group Item = 1 {
-      //       required int32 typeId = 2;
+      //       required uint32 typeId = 2;
       //       required bytes message = 3;
       //     }
       //   }

java/core/src/main/java/com/google/protobuf/Internal.java

@@ -259,7 +259,9 @@ public final class Internal {
 
   /** Helper method for implementing {@link Message#equals(Object)} for bytes field. */
   public static boolean equals(List<byte[]> a, List<byte[]> b) {
-    if (a.size() != b.size()) return false;
+    if (a.size() != b.size()) {
+      return false;
+    }
     for (int i = 0; i < a.size(); ++i) {
       if (!Arrays.equals(a.get(i), b.get(i))) {
         return false;

java/core/src/main/java/com/google/protobuf/MessageReflection.java

@@ -882,7 +882,7 @@ class MessageReflection {
     // The wire format for MessageSet is:
     //   message MessageSet {
     //     repeated group Item = 1 {
-    //       required int32 typeId = 2;
+    //       required uint32 typeId = 2;
     //       required bytes message = 3;
     //     }
     //   }

java/core/src/main/java/com/google/protobuf/MessageSetSchema.java

@@ -300,7 +300,7 @@ final class MessageSetSchema<T> implements Schema<T> {
     // The wire format for MessageSet is:
     //   message MessageSet {
     //     repeated group Item = 1 {
-    //       required int32 typeId = 2;
+    //       required uint32 typeId = 2;
     //       required bytes message = 3;
     //     }
     //   }

java/core/src/main/java/com/google/protobuf/TextFormat.java

@@ -49,7 +49,7 @@ import java.util.regex.Pattern;
 
 /**
  * Provide text parsing and formatting support for proto2 instances. The implementation largely
- * follows google/protobuf/text_format.cc.
+ * follows text_format.cc.
  *
  * @author wenboz@google.com Wenbo Zhu
  * @author kenton@google.com Kenton Varda
@@ -2307,7 +2307,7 @@ public final class TextFormat {
    * Un-escape a byte sequence as escaped using {@link #escapeBytes(ByteString)}. Two-digit hex
    * escapes (starting with "\x") are also recognized.
    */
-  public static ByteString unescapeBytes(final CharSequence charString)
+  public static ByteString unescapeBytes(CharSequence charString)
       throws InvalidEscapeSequenceException {
     // First convert the Java character sequence to UTF-8 bytes.
     ByteString input = ByteString.copyFromUtf8(charString.toString());
@@ -2444,9 +2444,10 @@ public final class TextFormat {
                           + "' is not a valid code point value");
                 }
                 Character.UnicodeBlock unicodeBlock = Character.UnicodeBlock.of(codepoint);
-                if (unicodeBlock.equals(Character.UnicodeBlock.LOW_SURROGATES)
+                if (unicodeBlock != null
+                        && (unicodeBlock.equals(Character.UnicodeBlock.LOW_SURROGATES)
                     || unicodeBlock.equals(Character.UnicodeBlock.HIGH_SURROGATES)
-                    || unicodeBlock.equals(Character.UnicodeBlock.HIGH_PRIVATE_USE_SURROGATES)) {
+                    || unicodeBlock.equals(Character.UnicodeBlock.HIGH_PRIVATE_USE_SURROGATES))) {
                   throw new InvalidEscapeSequenceException(
                       "Invalid escape sequence: '\\U"
                           + input.substring(i, i + 8).toStringUtf8()

java/core/src/main/java/com/google/protobuf/TextFormatEscaper.java

@@ -30,7 +30,24 @@
 
 package com.google.protobuf;
 
-/** Provide text format escaping support for proto2 instances. */
+/**
+ * Provide text format escaping of proto instances. These ASCII characters are escaped:
+ *
+ * ASCII #7   (bell) --> \a
+ * ASCII #8   (backspace) --> \b
+ * ASCII #9   (horizontal tab) --> \t
+ * ASCII #10  (linefeed) --> \n
+ * ASCII #11  (vertical tab) --> \v
+ * ASCII #13  (carriage return) --> \r
+ * ASCII #12  (formfeed) --> \f
+ * ASCII #34  (apostrophe) --> \'
+ * ASCII #39  (straight double quote) --> \"
+ * ASCII #92  (backslash) --> \\
+ *
+ * Other printable ASCII characters between 32 and 127 inclusive are output as is, unescaped.
+ * Other ASCII characters less than 32 and all Unicode characters 128 or greater are
+ * first encoded as UTF-8, then each byte is escaped individually as a 3-digit octal escape.
+ */
 final class TextFormatEscaper {
   private TextFormatEscaper() {}
 
@@ -41,17 +58,13 @@ final class TextFormatEscaper {
   }
 
   /**
-   * Escapes bytes in the format used in protocol buffer text format, which is the same as the
-   * format used for C string literals. All bytes that are not printable 7-bit ASCII characters are
-   * escaped, as well as backslash, single-quote, and double-quote characters. Characters for which
-   * no defined short-hand escape sequence is defined will be escaped using 3-digit octal sequences.
+   * Backslash escapes bytes in the format used in protocol buffer text format.
    */
-  static String escapeBytes(final ByteSequence input) {
+  static String escapeBytes(ByteSequence input) {
     final StringBuilder builder = new StringBuilder(input.size());
     for (int i = 0; i < input.size(); i++) {
-      final byte b = input.byteAt(i);
+      byte b = input.byteAt(i);
       switch (b) {
-          // Java does not recognize \a or \v, apparently.
         case 0x07:
           builder.append("\\a");
           break;
@@ -100,10 +113,7 @@ final class TextFormatEscaper {
   }
 
   /**
-   * Escapes bytes in the format used in protocol buffer text format, which is the same as the
-   * format used for C string literals. All bytes that are not printable 7-bit ASCII characters are
-   * escaped, as well as backslash, single-quote, and double-quote characters. Characters for which
-   * no defined short-hand escape sequence is defined will be escaped using 3-digit octal sequences.
+   * Backslash escapes bytes in the format used in protocol buffer text format.
    */
   static String escapeBytes(final ByteString input) {
     return escapeBytes(
@@ -137,16 +147,14 @@ final class TextFormatEscaper {
   }
 
   /**
-   * Like {@link #escapeBytes(ByteString)}, but escapes a text string. Non-ASCII characters are
-   * first encoded as UTF-8, then each byte is escaped individually as a 3-digit octal escape. Yes,
-   * it's weird.
+   * Like {@link #escapeBytes(ByteString)}, but escapes a text string.
    */
-  static String escapeText(final String input) {
+  static String escapeText(String input) {
     return escapeBytes(ByteString.copyFromUtf8(input));
   }
 
   /** Escape double quotes and backslashes in a String for unicode output of a message. */
-  static String escapeDoubleQuotesAndBackslashes(final String input) {
+  static String escapeDoubleQuotesAndBackslashes(String input) {
     return input.replace("\\", "\\\\").replace("\"", "\\\"");
   }
 }

java/core/src/main/java/com/google/protobuf/Utf8.java

@@ -64,9 +64,9 @@ import java.nio.ByteBuffer;
  * <em>Well Formed UTF-8 Byte Sequences</em>.
  *
  * <p>This class supports decoding of partial byte sequences, so that the bytes in a complete UTF-8
- * byte sequences can be stored in multiple segments. Methods typically return {@link #MALFORMED} if
- * the partial byte sequence is definitely not well-formed, {@link #COMPLETE} if it is well-formed
- * in the absence of additional input, or if the byte sequence apparently terminated in the middle
+ * byte sequence can be stored in multiple segments. Methods typically return {@link #MALFORMED} if
+ * the partial byte sequence is definitely not well-formed; {@link #COMPLETE} if it is well-formed
+ * in the absence of additional input; or, if the byte sequence apparently terminated in the middle
  * of a character, an opaque integer "state" value containing enough information to decode the
  * character when passed to a subsequent invocation of a partial decoding method.
  *

java/core/src/test/java/com/google/protobuf/TextFormatTest.java

@@ -170,6 +170,13 @@ public class TextFormatTest {
     assertThat(javaText).isEqualTo(ALL_FIELDS_SET_TEXT);
   }
 
+  @Test
+  // https://github.com/protocolbuffers/protobuf/issues/9447
+  public void testCharacterNotInUnicodeBlock() throws TextFormat.InvalidEscapeSequenceException {
+    ByteString actual = TextFormat.unescapeBytes("\\U000358da");
+    assertThat(actual.size()).isEqualTo(4);
+  }
+
   /** Print TestAllTypes as Builder and compare with golden file. */
   @Test
   public void testPrintMessageBuilder() throws Exception {

java/core/src/test/proto/com/google/protobuf/test_bad_identifiers.proto

@@ -41,10 +41,61 @@ option java_generic_services = true;  // auto-added
 option java_package = "com.google.protobuf";
 option java_outer_classname = "TestBadIdentifiersProto";
 
-message TestMessage {
-  optional string cached_size = 1;
-  optional string serialized_size = 2;
-  optional string class = 3;
+// Message with field names using underscores that conflict with accessors in the base message class in java.
+// See kForbiddenWordList in src/google/protobuf/compiler/java/java_helpers.cc
+message ForbiddenWordsUnderscoreMessage {
+  // java.lang.Object
+  optional bool class = 1;
+  // com.google.protobuf.MessageLiteOrBuilder
+  optional bool default_instance_for_type = 2;
+  // com.google.protobuf.MessageLite
+  optional bool parser_for_type = 3;
+  optional bool serialized_size = 4;
+  // com.google.protobuf.MessageOrBuilder
+  optional bool all_fields = 5;
+  optional bool descriptor_for_type = 6;
+  optional bool initialization_error_string = 7;
+  optional bool unknown_fields = 8;
+  // obsolete. kept for backwards compatibility of generated code
+  optional bool cached_size = 9;
+}
+
+// Message with field names using leading underscores that conflict with accessors in the base message class in java.
+// See kForbiddenWordList in src/google/protobuf/compiler/java/java_helpers.cc
+message ForbiddenWordsLeadingUnderscoreMessage {
+  // java.lang.Object
+  optional bool _class = 1;
+  // com.google.protobuf.MessageLiteOrBuilder
+  optional bool _default_instance_for_type = 2;
+  // com.google.protobuf.MessageLite
+  optional bool _parser_for_type = 3;
+  optional bool _serialized_size = 4;
+  // com.google.protobuf.MessageOrBuilder
+  optional bool _all_fields = 5;
+  optional bool _descriptor_for_type = 6;
+  optional bool _initialization_error_string = 7;
+  optional bool _unknown_fields = 8;
+  // obsolete. kept for backwards compatibility of generated code
+  optional bool _cached_size = 9;
+}
+
+// Message with field names in camel case that conflict with accessors in the base message class in java.
+// See kForbiddenWordList in src/google/protobuf/compiler/java/java_helpers.cc
+message ForbiddenWordsCamelMessage {
+  // java.lang.Object
+  optional bool class = 1;
+  // com.google.protobuf.MessageLiteOrBuilder
+  optional bool defaultInstanceForType = 2;
+  // com.google.protobuf.MessageLite
+  optional bool serializedSize = 3;
+  optional bool parserForType = 4;
+  // com.google.protobuf.MessageOrBuilder:
+  optional bool initializationErrorString = 5;
+  optional bool descriptorForType = 6;
+  optional bool allFields = 7;
+  optional bool unknownFields = 8;
+  // obsolete. kept for backwards compatibility of generated code
+  optional bool cachedSize = 9;
 }
 
 message Descriptor {
@@ -82,7 +133,7 @@ message Deprecated {
 
   optional int32 field1 = 1 [deprecated = true];
   optional TestEnum field2 = 2 [deprecated = true];
-  optional TestMessage field3 = 3 [deprecated = true];
+  optional ForbiddenWordsUnderscoreMessage field3 = 3 [deprecated = true];
 }
 
 message Override {
@@ -115,7 +166,7 @@ message Double {
 }
 
 service TestConflictingMethodNames {
-  rpc Override(TestMessage) returns (TestMessage);
+  rpc Override(ForbiddenWordsUnderscoreMessage) returns (ForbiddenWordsUnderscoreMessage);
 }
 
 message TestConflictingFieldNames {
@@ -123,24 +174,24 @@ message TestConflictingFieldNames {
     UNKNOWN = 0;
     FOO = 1;
   }
-  message TestMessage {}
+  message ForbiddenWordsUnderscoreMessage {}
   repeated int32 int32_field = 1;
   repeated TestEnum enum_field = 2;
   repeated string string_field = 3;
   repeated bytes bytes_field = 4;
-  repeated TestMessage message_field = 5;
+  repeated ForbiddenWordsUnderscoreMessage message_field = 5;
 
   optional int32 int32_field_count = 11;
   optional TestEnum enum_field_count = 12;
   optional string string_field_count = 13;
   optional bytes bytes_field_count = 14;
-  optional TestMessage message_field_count = 15;
+  optional ForbiddenWordsUnderscoreMessage message_field_count = 15;
 
   repeated int32 Int32Field = 21;          // NO_PROTO3
   repeated TestEnum EnumField = 22;        // NO_PROTO3
   repeated string StringField = 23;        // NO_PROTO3
   repeated bytes BytesField = 24;          // NO_PROTO3
-  repeated TestMessage MessageField = 25;  // NO_PROTO3
+  repeated ForbiddenWordsUnderscoreMessage MessageField = 25;  // NO_PROTO3
 
   // This field conflicts with "int32_field" as they both generate
   // the method getInt32FieldList().

java/kotlin/src/main/kotlin/com/google/protobuf/Anies.kt

@@ -0,0 +1,45 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf.kotlin
+
+import com.google.protobuf.Any as ProtoAny
+import com.google.protobuf.Message
+
+/** Returns `true` if this [com.google.protobuf.Any] contains a message of type `T`. */
+inline fun <reified T : Message> ProtoAny.isA(): Boolean = this.`is`(T::class.java)
+
+/**
+ * Returns the message of type `T` encoded in this [com.google.protobuf.Any].
+ *
+ * @throws InvalidProtocolBufferException if this [com.google.protobuf.Any] does not contain a `T`
+ * message.
+ */
+inline fun <reified T : Message> ProtoAny.unpack(): T = unpack(T::class.java)

java/kotlin/src/test/kotlin/com/google/protobuf/AniesTest.kt

@@ -0,0 +1,70 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf.kotlin
+
+import com.google.common.truth.Truth.assertThat
+import com.google.protobuf.Any as ProtoAny
+import com.google.protobuf.InvalidProtocolBufferException
+import protobuf_unittest.UnittestProto.BoolMessage
+import protobuf_unittest.UnittestProto.Int32Message
+import protobuf_unittest.int32Message
+import kotlin.test.assertFailsWith
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+/** Tests for extension methods on [ProtoAny]. */
+@RunWith(JUnit4::class)
+class AniesTest {
+  companion object {
+    val anAny = ProtoAny.pack(int32Message { data = 5 })
+  }
+
+  @Test
+  fun isA_Positive() {
+    assertThat(anAny.isA<Int32Message>()).isTrue()
+  }
+
+  @Test
+  fun isA_Negative() {
+    assertThat(anAny.isA<BoolMessage>()).isFalse()
+  }
+
+  @Test
+  fun unpackValid() {
+    assertThat(anAny.unpack<Int32Message>().data).isEqualTo(5)
+  }
+
+  @Test
+  fun unpackInvalid() {
+    assertFailsWith<InvalidProtocolBufferException> { anAny.unpack<BoolMessage>() }
+  }
+}

kokoro/linux/dockerfile/test/java_stretch/Dockerfile

@@ -1,4 +1,7 @@
-FROM debian:stretch
+# Despite the name of this image, we are no longer on stretch.
+# We should consider renaming this image, and/or evaluating what
+# software versions we actually need.
+FROM debian:bullseye
 
 # Install dependencies.  We start with the basic ones required to build protoc
 # and the C++ build
@@ -22,9 +25,11 @@ RUN apt-get update && apt-get install -y \
   wget \
   # Java dependencies
   maven \
-  openjdk-8-jdk \
+  openjdk-11-jdk \
+  # Required for the gtest build.
+  python2 \
   # Python dependencies
   python3-setuptools \
   python3-pip \
-  virtualenv \
+  python3-venv \
   && apt-get clean

kokoro/linux/python36/build.sh

@@ -1,18 +0,0 @@
-#!/bin/bash
-#
-# This is the top-level script we give to Kokoro as the entry point for
-# running the "pull request" project:
-#
-# This script selects a specific Dockerfile (for building a Docker image) and
-# a script to run inside that image.  Then we delegate to the general
-# build_and_run_docker.sh script.
-
-# Change to repo root
-cd $(dirname $0)/../../..
-
-export DOCKERHUB_ORGANIZATION=protobuftesting
-export DOCKERFILE_DIR=kokoro/linux/dockerfile/test/python36
-export DOCKER_RUN_SCRIPT=kokoro/linux/pull_request_in_docker.sh
-export OUTPUT_DIR=testoutput
-export TEST_SET="python36"
-./kokoro/linux/build_and_run_docker.sh

kokoro/linux/python36/continuous.cfg

@@ -1,11 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/linux/python36/build.sh"
-timeout_mins: 120
-
-action {
-  define_artifacts {
-    regex: "**/sponge_log.xml"
-  }
-}

kokoro/linux/python36/presubmit.cfg

@@ -1,11 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/linux/python36/build.sh"
-timeout_mins: 120
-
-action {
-  define_artifacts {
-    regex: "**/sponge_log.xml"
-  }
-}

kokoro/linux/python36_cpp/build.sh

@@ -1,18 +0,0 @@
-#!/bin/bash
-#
-# This is the top-level script we give to Kokoro as the entry point for
-# running the "pull request" project:
-#
-# This script selects a specific Dockerfile (for building a Docker image) and
-# a script to run inside that image.  Then we delegate to the general
-# build_and_run_docker.sh script.
-
-# Change to repo root
-cd $(dirname $0)/../../..
-
-export DOCKERHUB_ORGANIZATION=protobuftesting
-export DOCKERFILE_DIR=kokoro/linux/dockerfile/test/python36
-export DOCKER_RUN_SCRIPT=kokoro/linux/pull_request_in_docker.sh
-export OUTPUT_DIR=testoutput
-export TEST_SET="python36_cpp"
-./kokoro/linux/build_and_run_docker.sh

kokoro/linux/python36_cpp/continuous.cfg

@@ -1,11 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/linux/python36_cpp/build.sh"
-timeout_mins: 120
-
-action {
-  define_artifacts {
-    regex: "**/sponge_log.xml"
-  }
-}

kokoro/linux/python36_cpp/presubmit.cfg

@@ -1,11 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/linux/python36_cpp/build.sh"
-timeout_mins: 120
-
-action {
-  define_artifacts {
-    regex: "**/sponge_log.xml"
-  }
-}

kokoro/release/python/windows/build_artifacts.bat

@@ -40,16 +40,6 @@ mkdir %ARTIFACT_DIR%
 
 REM Build wheel
 
-SET PYTHON=C:\python36_32bit
-SET PYTHON_VERSION=3.6
-SET PYTHON_ARCH=32
-CALL build_single_artifact.bat || goto :error
-
-SET PYTHON=C:\python36
-SET PYTHON_VERSION=3.6
-SET PYTHON_ARCH=64
-CALL build_single_artifact.bat || goto :error
-
 SET PYTHON=C:\python37_32bit
 SET PYTHON_VERSION=3.7
 SET PYTHON_ARCH=32

kokoro/release/python/windows/build_single_artifact.bat

@@ -1,11 +1,5 @@
 setlocal
 
-if %PYTHON%==C:\python36_32bit set generator=Visual Studio 14
-if %PYTHON%==C:\python36_32bit set vcplatform=Win32
-
-if %PYTHON%==C:\python36 set generator=Visual Studio 14 Win64
-if %PYTHON%==C:\python36 set vcplatform=x64
-
 if %PYTHON%==C:\python37_32bit set generator=Visual Studio 14
 if %PYTHON%==C:\python37_32bit set vcplatform=Win32
 

objectivec/README.md

@@ -133,8 +133,8 @@ This options allow you to provide a custom prefix for all the symbols generated
 from a proto file (classes (from message), enums, the Root for extension
 support).
 
-If not set, the generation option `use_package_as_prefix` (documented below)
-controls what is used instead. Since Objective C uses a global namespace for all
+If not set, the generation options `default_objc_class_prefix` and `use_package_as_prefix`
+(documented below) control what is used instead. Since Objective C uses a global namespace for all
 of its classes, there can be collisions. `use_package_as_prefix=yes` should
 avoid collisions since proto package are used to scope/name things in other
 languages, but this option can be used to get shorter names instead. Convention
@@ -182,6 +182,12 @@ supported keys are:
     having to add the runtime directory to the header search path since the
     generate `#import` will be more complete.
 
+  * `default_objc_class_prefix`: The default ObjC prefix value to use when 
+    generating sources. The generator will use this if the `objc_class_prefix`
+    file option is not set. This option can be useful if multiple iOS apps
+    consume the same proto file but wish to use a different prefix for their
+    generated sources.
+
   * `use_package_as_prefix` and `proto_package_prefix_exceptions_path`: The
     `value` for `use_package_as_prefix` can be `yes` or `no`, and indicates
     if a prefix should be derived from the proto package for all the symbols

php/ext/google/protobuf/names.c

@@ -81,12 +81,13 @@ const char *const kReservedNames[] = {
     "if",         "implements",  "include",      "include_once", "instanceof",
     "global",     "goto",        "insteadof",    "interface",    "isset",
     "list",       "match",       "namespace",    "new",          "object",
-    "or",         "print",        "private",    "protected",    "public",
-    "require",    "require_once", "return",     "static",       "switch",
-    "throw",      "trait",        "try",        "unset",        "use",
-    "var",        "while",        "xor",        "yield",        "int",
-    "float",      "bool",         "string",     "true",         "false",
-    "null",       "void",         "iterable",   NULL};
+    "or",         "parent",      "print",        "private",      "protected",
+    "public",     "require",     "require_once", "return",       "self",
+    "static",     "switch",      "throw",        "trait",        "try",
+    "unset",      "use",         "var",          "while",        "xor",
+    "yield",      "int",         "float",        "bool",         "string",
+    "true",       "false",       "null",         "void",         "iterable",
+    NULL};
 
 bool is_reserved_name(const char* name) {
   int i;

php/src/Google/Protobuf/Internal/DescriptorPool.php

@@ -159,7 +159,7 @@ class DescriptorPool
                     if (is_null($subdesc)) {
                         trigger_error(
                             'proto not added: ' . $proto
-                            . " for " . $desc->getFullName(), E_ERROR);
+                            . " for " . $desc->getFullName(), E_USER_ERROR);
                     }
                     $field->setMessageType($subdesc);
                     break;

php/src/Google/Protobuf/Internal/GPBUtil.php

@@ -284,12 +284,12 @@ class GPBUtil
             "function"=>0, "global"=>0, "goto"=>0, "if"=>0, "implements"=>0,
             "include"=>0, "include_once"=>0, "instanceof"=>0, "insteadof"=>0,
             "interface"=>0, "isset"=>0, "list"=>0, "match"=>0, "namespace"=>0,
-            "new"=>0, "or"=>0, "print"=>0, "private"=>0, "protected"=>0,
-            "public"=>0, "require"=>0, "require_once"=>0, "return"=>0,
-            "static"=>0, "switch"=>0, "throw"=>0, "trait"=>0, "try"=>0,
-            "unset"=>0, "use"=>0, "var"=>0, "while"=>0, "xor"=>0, "yield"=>0,
-            "int"=>0, "float"=>0, "bool"=>0, "string"=>0, "true"=>0, "false"=>0,
-            "null"=>0, "void"=>0, "iterable"=>0
+            "new"=>0, "or"=>0, "parent"=>0, "print"=>0, "private"=>0,
+            "protected"=>0,"public"=>0, "require"=>0, "require_once"=>0,
+            "return"=>0, "self"=>0, "static"=>0, "switch"=>0, "throw"=>0,
+            "trait"=>0, "try"=>0,"unset"=>0, "use"=>0, "var"=>0, "while"=>0,
+            "xor"=>0, "yield"=>0, "int"=>0, "float"=>0, "bool"=>0, "string"=>0,
+            "true"=>0, "false"=>0, "null"=>0, "void"=>0, "iterable"=>0
         );
 
         if (array_key_exists(strtolower($classname), $reserved_words)) {

php/src/Google/Protobuf/Internal/Message.php

@@ -423,7 +423,7 @@ class Message
                 }
                 break;
             case GPBType::GROUP:
-                trigger_error("Not implemented.", E_ERROR);
+                trigger_error("Not implemented.", E_USER_ERROR);
                 break;
             case GPBType::MESSAGE:
                 if ($field->isMap()) {

php/tests/GeneratedClassTest.php

@@ -934,6 +934,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Lower\PBnamespace();
         $m = new \Lower\PBnew();
         $m = new \Lower\PBor();
+        $m = new \Lower\PBparent();
         $m = new \Lower\PBprint();
         $m = new \Lower\PBprivate();
         $m = new \Lower\PBprotected();
@@ -941,6 +942,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Lower\PBrequire();
         $m = new \Lower\PBrequire_once();
         $m = new \Lower\PBreturn();
+        $m = new \Lower\PBself();
         $m = new \Lower\PBstatic();
         $m = new \Lower\PBswitch();
         $m = new \Lower\PBthrow();
@@ -1012,6 +1014,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Upper\PBNAMESPACE();
         $m = new \Upper\PBNEW();
         $m = new \Upper\PBOR();
+        $m = new \Upper\PBPARENT();
         $m = new \Upper\PBPRINT();
         $m = new \Upper\PBPRIVATE();
         $m = new \Upper\PBPROTECTED();
@@ -1019,6 +1022,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Upper\PBREQUIRE();
         $m = new \Upper\PBREQUIRE_ONCE();
         $m = new \Upper\PBRETURN();
+        $m = new \Upper\PBSELF();
         $m = new \Upper\PBSTATIC();
         $m = new \Upper\PBSWITCH();
         $m = new \Upper\PBTHROW();
@@ -1090,6 +1094,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Lower_enum\PBnamespace();
         $m = new \Lower_enum\PBnew();
         $m = new \Lower_enum\PBor();
+        $m = new \Lower_enum\PBparent();
         $m = new \Lower_enum\PBprint();
         $m = new \Lower_enum\PBprivate();
         $m = new \Lower_enum\PBprotected();
@@ -1097,6 +1102,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Lower_enum\PBrequire();
         $m = new \Lower_enum\PBrequire_once();
         $m = new \Lower_enum\PBreturn();
+        $m = new \Lower_enum\PBself();
         $m = new \Lower_enum\PBstatic();
         $m = new \Lower_enum\PBswitch();
         $m = new \Lower_enum\PBthrow();
@@ -1168,6 +1174,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Upper_enum\PBNAMESPACE();
         $m = new \Upper_enum\PBNEW();
         $m = new \Upper_enum\PBOR();
+        $m = new \Upper_enum\PBPARENT();
         $m = new \Upper_enum\PBPRINT();
         $m = new \Upper_enum\PBPRIVATE();
         $m = new \Upper_enum\PBPROTECTED();
@@ -1175,6 +1182,7 @@ class GeneratedClassTest extends TestBase
         $m = new \Upper_enum\PBREQUIRE();
         $m = new \Upper_enum\PBREQUIRE_ONCE();
         $m = new \Upper_enum\PBRETURN();
+        $m = new \Upper_enum\PBSELF();
         $m = new \Upper_enum\PBSTATIC();
         $m = new \Upper_enum\PBSWITCH();
         $m = new \Upper_enum\PBTHROW();
@@ -1273,6 +1281,8 @@ class GeneratedClassTest extends TestBase
         $m = \Lower_enum_value\NotAllowed::null;
         $m = \Lower_enum_value\NotAllowed::void;
         $m = \Lower_enum_value\NotAllowed::iterable;
+        $m = \Lower_enum_value\NotAllowed::parent;
+        $m = \Lower_enum_value\NotAllowed::self;
 
         $m = \Upper_enum_value\NotAllowed::PBABSTRACT;
         $m = \Upper_enum_value\NotAllowed::PBAND;
@@ -1351,6 +1361,8 @@ class GeneratedClassTest extends TestBase
         $m = \Upper_enum_value\NotAllowed::NULL;
         $m = \Upper_enum_value\NotAllowed::VOID;
         $m = \Upper_enum_value\NotAllowed::ITERABLE;
+        $m = \Upper_enum_value\NotAllowed::PARENT;
+        $m = \Upper_enum_value\NotAllowed::SELF;
 
         $this->assertTrue(true);
     }

php/tests/proto/test_reserved_enum_lower.proto

@@ -52,6 +52,7 @@ enum match { ZERO47 = 0; }
 enum namespace { ZERO48 = 0; }
 enum new { ZERO49 = 0; }
 enum or { ZERO50 = 0; }
+enum parent { ZERO78 = 0; }
 enum print { ZERO51 = 0; }
 enum private { ZERO52 = 0; }
 enum protected { ZERO53 = 0; }
@@ -59,6 +60,7 @@ enum public { ZERO54 = 0; }
 enum require { ZERO55 = 0; }
 enum require_once { ZERO56 = 0; }
 enum return { ZERO57 = 0; }
+enum self { ZERO79 = 0; }
 enum static { ZERO58 = 0; }
 enum switch { ZERO59 = 0; }
 enum throw { ZERO60 = 0; }

php/tests/proto/test_reserved_enum_upper.proto

@@ -52,6 +52,7 @@ enum MATCH { ZERO47 = 0; }
 enum NAMESPACE { ZERO48 = 0; }
 enum NEW { ZERO49 = 0; }
 enum OR { ZERO50 = 0; }
+enum PARENT { ZERO78 = 0; }
 enum PRINT { ZERO51 = 0; }
 enum PRIVATE { ZERO52 = 0; }
 enum PROTECTED { ZERO53 = 0; }
@@ -59,6 +60,7 @@ enum PUBLIC { ZERO54 = 0; }
 enum REQUIRE { ZERO55 = 0; }
 enum REQUIRE_ONCE { ZERO56 = 0; }
 enum RETURN { ZERO57 = 0; }
+enum SELF { ZERO79 = 0; }
 enum STATIC { ZERO58 = 0; }
 enum SWITCH { ZERO59 = 0; }
 enum THROW { ZERO60 = 0; }

php/tests/proto/test_reserved_enum_value_lower.proto

@@ -53,6 +53,7 @@ enum NotAllowed {
   namespace = 47;
   new = 48;
   or = 49;
+  parent = 77;
   print = 50;
   private = 51;
   protected = 52;
@@ -60,6 +61,7 @@ enum NotAllowed {
   require = 54;
   require_once = 55;
   return = 56;
+  self = 78;
   static = 57;
   switch = 58;
   throw = 59;

php/tests/proto/test_reserved_enum_value_upper.proto

@@ -53,6 +53,7 @@ enum NotAllowed {
   NAMESPACE = 47;
   NEW = 48;
   OR = 49;
+  PARENT = 77;
   PRINT = 50;
   PRIVATE = 51;
   PROTECTED = 52;
@@ -60,6 +61,7 @@ enum NotAllowed {
   REQUIRE = 54;
   REQUIRE_ONCE = 55;
   RETURN = 56;
+  SELF = 78;
   STATIC = 57;
   SWITCH = 58;
   THROW = 59;

php/tests/proto/test_reserved_message_lower.proto

@@ -52,6 +52,7 @@ message match {}
 message namespace {}
 message new {}
 message or {}
+message parent {}
 message print {}
 message private {}
 message protected {}
@@ -59,6 +60,7 @@ message public {}
 message require {}
 message require_once {}
 message return {}
+message self {}
 message static {}
 message switch {}
 message throw {}

php/tests/proto/test_reserved_message_upper.proto

@@ -52,6 +52,7 @@ message MATCH {}
 message NAMESPACE {}
 message NEW {}
 message OR {}
+message PARENT {}
 message PRINT {}
 message PRIVATE {}
 message PROTECTED {}
@@ -59,6 +60,7 @@ message PUBLIC {}
 message REQUIRE {}
 message REQUIRE_ONCE {}
 message RETURN {}
+message SELF {}
 message STATIC {}
 message SWITCH {}
 message THROW {}

python/README.md

@@ -26,7 +26,7 @@ use python c++ implementation.
 Installation
 ============
 
-1) Make sure you have Python 3.5 or newer.  If in doubt, run:
+1) Make sure you have Python 3.7 or newer.  If in doubt, run:
 
        $ python -V
 

python/google/protobuf/internal/descriptor_pool_test.py

@@ -541,7 +541,13 @@ class DescriptorPoolTestBase(object):
       pool._AddExtensionDescriptor(
           file_descriptor.extensions_by_name['optional_int32_extension'])
       pool.Add(unittest_fd)
+      with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter('always')
         pool.Add(conflict_fd)
+        self.assertTrue(len(w))
+        self.assertIs(w[0].category, RuntimeWarning)
+        self.assertIn('Conflict register for file "other_file": ',
+                      str(w[0].message))
       pool.FindFileByName(unittest_fd.name)
       with self.assertRaises(TypeError):
         pool.FindFileByName(conflict_fd.name)

python/google/protobuf/json_format.py

@@ -95,7 +95,8 @@ def MessageToJson(
     sort_keys=False,
     use_integers_for_enums=False,
     descriptor_pool=None,
-    float_precision=None):
+    float_precision=None,
+    ensure_ascii=True):
   """Converts protobuf message to JSON format.
 
   Args:
@@ -114,6 +115,8 @@ def MessageToJson(
     descriptor_pool: A Descriptor Pool for resolving types. If None use the
         default.
     float_precision: If set, use this to specify float field valid digits.
+    ensure_ascii: If True, strings with non-ASCII characters are escaped.
+        If False, Unicode strings are returned unchanged.
 
   Returns:
     A string containing the JSON formatted protocol buffer message.
@@ -124,7 +127,7 @@ def MessageToJson(
       use_integers_for_enums,
       descriptor_pool,
       float_precision=float_precision)
-  return printer.ToJsonString(message, indent, sort_keys)
+  return printer.ToJsonString(message, indent, sort_keys, ensure_ascii)
 
 
 def MessageToDict(
@@ -190,9 +193,10 @@ class _Printer(object):
     else:
       self.float_format = None
 
-  def ToJsonString(self, message, indent, sort_keys):
+  def ToJsonString(self, message, indent, sort_keys, ensure_ascii):
     js = self._MessageToJsonObject(message)
-    return json.dumps(js, indent=indent, sort_keys=sort_keys)
+    return json.dumps(
+        js, indent=indent, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
 
   def _MessageToJsonObject(self, message):
     """Converts message to an object according to Proto3 JSON Specification."""

python/google/protobuf/pyext/message.cc

@@ -1002,7 +1002,7 @@ int DeleteRepeatedField(
     }
   }
 
-  Arena* arena = Arena::InternalHelper<Message>::GetArenaForAllocation(message);
+  Arena* arena = Arena::InternalGetArenaForAllocation(message);
   GOOGLE_DCHECK_EQ(arena, nullptr)
       << "python protobuf is expected to be allocated from heap";
   // Remove items, starting from the end.

python/google/protobuf/pyext/unknown_fields.cc

@@ -138,8 +138,9 @@ static void Dealloc(PyObject* pself) {
     reinterpret_cast<CMessage*>(self->parent)->unknown_field_set = nullptr;
   }
   Py_CLEAR(self->parent);
+  auto* py_type = Py_TYPE(pself);
   self->~PyUnknownFields();
-  Py_TYPE(pself)->tp_free(pself);
+  py_type->tp_free(pself);
 }
 
 static PySequenceMethods SqMethods = {

python/google/protobuf/service_reflection.py

@@ -133,7 +133,7 @@ class _ServiceBuilder(object):
     """
     self.descriptor = service_descriptor
 
-  def BuildService(self, cls):
+  def BuildService(builder, cls):
     """Constructs the service class.
 
     Args:
@@ -143,18 +143,25 @@ class _ServiceBuilder(object):
     # CallMethod needs to operate with an instance of the Service class. This
     # internal wrapper function exists only to be able to pass the service
     # instance to the method that does the real CallMethod work.
-    def _WrapCallMethod(srvc, method_descriptor,
-                        rpc_controller, request, callback):
-      return self._CallMethod(srvc, method_descriptor,
-                       rpc_controller, request, callback)
-    self.cls = cls
+    # Making sure to use exact argument names from the abstract interface in
+    # service.py to match the type signature
+    def _WrapCallMethod(self, method_descriptor,
+                        rpc_controller, request, done):
+      return builder._CallMethod(self, method_descriptor,
+                       rpc_controller, request, done)
+    def _WrapGetRequestClass(self, method_descriptor):
+      return builder._GetRequestClass(method_descriptor)
+    def _WrapGetResponseClass(self, method_descriptor):
+      return builder._GetResponseClass(method_descriptor)
+
+    builder.cls = cls
     cls.CallMethod = _WrapCallMethod
-    cls.GetDescriptor = staticmethod(lambda: self.descriptor)
+    cls.GetDescriptor = staticmethod(lambda: builder.descriptor)
     cls.GetDescriptor.__doc__ = "Returns the service descriptor."
-    cls.GetRequestClass = self._GetRequestClass
-    cls.GetResponseClass = self._GetResponseClass
-    for method in self.descriptor.methods:
-      setattr(cls, method.name, self._GenerateNonImplementedMethod(method))
+    cls.GetRequestClass = _WrapGetRequestClass
+    cls.GetResponseClass = _WrapGetResponseClass
+    for method in builder.descriptor.methods:
+      setattr(cls, method.name, builder._GenerateNonImplementedMethod(method))
 
   def _CallMethod(self, srvc, method_descriptor,
                   rpc_controller, request, callback):

python/setup.py

@@ -301,11 +301,10 @@ if __name__ == '__main__':
       classifiers=[
           "Programming Language :: Python",
           "Programming Language :: Python :: 3",
-          "Programming Language :: Python :: 3.3",
-          "Programming Language :: Python :: 3.4",
-          "Programming Language :: Python :: 3.5",
-          "Programming Language :: Python :: 3.6",
           "Programming Language :: Python :: 3.7",
+          "Programming Language :: Python :: 3.8",
+          "Programming Language :: Python :: 3.9",
+          "Programming Language :: Python :: 3.10",
       ],
       namespace_packages=['google'],
       packages=find_packages(
@@ -322,5 +321,5 @@ if __name__ == '__main__':
       },
       install_requires=install_requires,
       ext_modules=ext_module_list,
-      python_requires=">=3.5",
+      python_requires=">=3.7",
   )

python/tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{35,36,37,38,39,310}-{cpp,python}
+    py{37,38,39,310}-{cpp,python}
 
 [testenv]
 usedevelop=true
@@ -14,7 +14,7 @@ setenv =
 commands =
     python setup.py -q build_py
     python: python setup.py -q build
-    py{35,36,37,38,39,310}-cpp: python setup.py -q build --cpp_implementation --warnings_as_errors --compile_static_extension
+    py{37,38,39,310}-cpp: python setup.py -q build --cpp_implementation --warnings_as_errors --compile_static_extension
     python: python setup.py -q test -q
     cpp: python setup.py -q test -q --cpp_implementation
     python: python setup.py -q test_conformance

ruby/ext/google/protobuf_c/message.c

@@ -953,13 +953,35 @@ static VALUE Message_index_set(VALUE _self, VALUE field_name, VALUE value) {
 
 /*
  * call-seq:
- *     MessageClass.decode(data) => message
+ *     MessageClass.decode(data, options) => message
  *
  * Decodes the given data (as a string containing bytes in protocol buffers wire
  * format) under the interpretration given by this message class's definition
  * and returns a message object with the corresponding field values.
+ * @param options [Hash] options for the decoder
+ *  recursion_limit: set to maximum decoding depth for message (default is 64)
  */
-static VALUE Message_decode(VALUE klass, VALUE data) {
+static VALUE Message_decode(int argc, VALUE* argv, VALUE klass) {
+  VALUE data = argv[0];
+  int options = 0;
+
+  if (argc < 1 || argc > 2) {
+    rb_raise(rb_eArgError, "Expected 1 or 2 arguments.");
+  }
+
+  if (argc == 2) {
+    VALUE hash_args = argv[1];
+    if (TYPE(hash_args) != T_HASH) {
+      rb_raise(rb_eArgError, "Expected hash arguments.");
+    }
+
+    VALUE depth = rb_hash_lookup(hash_args, ID2SYM(rb_intern("recursion_limit")));
+
+    if (depth != Qnil && TYPE(depth) == T_FIXNUM) {
+      options |= UPB_DECODE_MAXDEPTH(FIX2INT(depth));
+    }
+  }
+
   if (TYPE(data) != T_STRING) {
     rb_raise(rb_eArgError, "Expected string for binary protobuf data.");
   }
@@ -969,7 +991,7 @@ static VALUE Message_decode(VALUE klass, VALUE data) {
 
   upb_DecodeStatus status = upb_Decode(
       RSTRING_PTR(data), RSTRING_LEN(data), (upb_Message*)msg->msg,
-      upb_MessageDef_MiniTable(msg->msgdef), NULL, 0, Arena_get(msg->arena));
+      upb_MessageDef_MiniTable(msg->msgdef), NULL, options, Arena_get(msg->arena));
 
   if (status != kUpb_DecodeStatus_Ok) {
     rb_raise(cParseError, "Error occurred during parsing");
@@ -1043,24 +1065,43 @@ static VALUE Message_decode_json(int argc, VALUE* argv, VALUE klass) {
 
 /*
  * call-seq:
- *     MessageClass.encode(msg) => bytes
+ *     MessageClass.encode(msg, options) => bytes
  *
  * Encodes the given message object to its serialized form in protocol buffers
  * wire format.
+ * @param options [Hash] options for the encoder
+ *  recursion_limit: set to maximum encoding depth for message (default is 64)
  */
-static VALUE Message_encode(VALUE klass, VALUE msg_rb) {
-  Message* msg = ruby_to_Message(msg_rb);
+static VALUE Message_encode(int argc, VALUE* argv, VALUE klass) {
+  Message* msg = ruby_to_Message(argv[0]);
+  int options = 0;
   const char* data;
   size_t size;
 
-  if (CLASS_OF(msg_rb) != klass) {
+  if (CLASS_OF(argv[0]) != klass) {
     rb_raise(rb_eArgError, "Message of wrong type.");
   }
 
+  if (argc < 1 || argc > 2) {
+    rb_raise(rb_eArgError, "Expected 1 or 2 arguments.");
+  }
+
+  if (argc == 2) {
+    VALUE hash_args = argv[1];
+    if (TYPE(hash_args) != T_HASH) {
+      rb_raise(rb_eArgError, "Expected hash arguments.");
+    }
+    VALUE depth = rb_hash_lookup(hash_args, ID2SYM(rb_intern("recursion_limit")));
+
+    if (depth != Qnil && TYPE(depth) == T_FIXNUM) {
+      options |= UPB_DECODE_MAXDEPTH(FIX2INT(depth));
+    }
+  }
+
   upb_Arena *arena = upb_Arena_New();
 
-  data = upb_Encode(msg->msg, upb_MessageDef_MiniTable(msg->msgdef), 0, arena,
-                    &size);
+  data = upb_Encode(msg->msg, upb_MessageDef_MiniTable(msg->msgdef),
+                    options, arena, &size);
 
   if (data) {
     VALUE ret = rb_str_new(data, size);
@@ -1186,8 +1227,8 @@ VALUE build_class_from_descriptor(VALUE descriptor) {
   rb_define_method(klass, "to_s", Message_inspect, 0);
   rb_define_method(klass, "[]", Message_index, 1);
   rb_define_method(klass, "[]=", Message_index_set, 2);
-  rb_define_singleton_method(klass, "decode", Message_decode, 1);
-  rb_define_singleton_method(klass, "encode", Message_encode, 1);
+  rb_define_singleton_method(klass, "decode", Message_decode, -1);
+  rb_define_singleton_method(klass, "encode", Message_encode, -1);
   rb_define_singleton_method(klass, "decode_json", Message_decode_json, -1);
   rb_define_singleton_method(klass, "encode_json", Message_encode_json, -1);
   rb_define_singleton_method(klass, "descriptor", Message_descriptor, 0);

ruby/lib/google/protobuf.rb

@@ -59,16 +59,16 @@ require 'google/protobuf/repeated_field'
 module Google
   module Protobuf
 
-    def self.encode(msg)
-      msg.to_proto
+    def self.encode(msg, options = {})
+      msg.to_proto(options)
     end
 
     def self.encode_json(msg, options = {})
       msg.to_json(options)
     end
 
-    def self.decode(klass, proto)
-      klass.decode(proto)
+    def self.decode(klass, proto, options = {})
+      klass.decode(proto, options)
     end
 
     def self.decode_json(klass, json, options = {})

ruby/lib/google/protobuf/message_exts.rb

@@ -44,8 +44,8 @@ module Google
         self.class.encode_json(self, options)
       end
 
-      def to_proto
-        self.class.encode(self)
+      def to_proto(options = {})
+        self.class.encode(self, options)
       end
 
     end

ruby/src/main/java/com/google/protobuf/jruby/RubyMap.java

@@ -389,7 +389,7 @@ public class RubyMap extends RubyObject {
         return newMap;
     }
 
-    protected List<DynamicMessage> build(ThreadContext context, RubyDescriptor descriptor, int depth) {
+    protected List<DynamicMessage> build(ThreadContext context, RubyDescriptor descriptor, int depth, int recursionLimit) {
         List<DynamicMessage> list = new ArrayList<DynamicMessage>();
         RubyClass rubyClass = (RubyClass) descriptor.msgclass(context);
         FieldDescriptor keyField = descriptor.getField("key");
@@ -398,7 +398,7 @@ public class RubyMap extends RubyObject {
             RubyMessage mapMessage = (RubyMessage) rubyClass.newInstance(context, Block.NULL_BLOCK);
             mapMessage.setField(context, keyField, key);
             mapMessage.setField(context, valueField, table.get(key));
-            list.add(mapMessage.build(context, depth + 1));
+            list.add(mapMessage.build(context, depth + 1, recursionLimit));
         }
         return list;
     }

ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java

@@ -39,6 +39,7 @@ import com.google.protobuf.Descriptors.FieldDescriptor;
 import com.google.protobuf.Descriptors.FileDescriptor;
 import com.google.protobuf.Descriptors.OneofDescriptor;
 import com.google.protobuf.ByteString;
+import com.google.protobuf.CodedInputStream;
 import com.google.protobuf.DynamicMessage;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.Message;
@@ -461,35 +462,63 @@ public class RubyMessage extends RubyObject {
 
     /*
      * call-seq:
-     *     MessageClass.encode(msg) => bytes
+     *     MessageClass.encode(msg, options = {}) => bytes
      *
      * Encodes the given message object to its serialized form in protocol buffers
      * wire format.
+     * @param options [Hash] options for the encoder
+     *  recursion_limit: set to maximum encoding depth for message (default is 64)
      */
-    @JRubyMethod(meta = true)
-    public static IRubyObject encode(ThreadContext context, IRubyObject recv, IRubyObject value) {
-        if (recv != value.getMetaClass()) {
-            throw context.runtime.newArgumentError("Tried to encode a " + value.getMetaClass() + " message with " + recv);
+    @JRubyMethod(required = 1, optional = 1, meta = true)
+    public static IRubyObject encode(ThreadContext context, IRubyObject recv, IRubyObject[] args) {
+        if (recv != args[0].getMetaClass()) {
+            throw context.runtime.newArgumentError("Tried to encode a " + args[0].getMetaClass() + " message with " + recv);
         }
-        RubyMessage message = (RubyMessage) value;
-        return context.runtime.newString(new ByteList(message.build(context).toByteArray()));
+        RubyMessage message = (RubyMessage) args[0];
+        int recursionLimitInt = SINK_MAXIMUM_NESTING;
+
+        if (args.length > 1) {
+            RubyHash options = (RubyHash) args[1];
+            IRubyObject recursionLimit = options.fastARef(context.runtime.newSymbol("recursion_limit"));
+
+            if (recursionLimit != null) {
+                recursionLimitInt = ((RubyNumeric) recursionLimit).getIntValue();
+            }
+        }
+        return context.runtime.newString(new ByteList(message.build(context, 0, recursionLimitInt).toByteArray()));
     }
 
     /*
      * call-seq:
-     *     MessageClass.decode(data) => message
+     *     MessageClass.decode(data, options = {}) => message
      *
      * Decodes the given data (as a string containing bytes in protocol buffers wire
      * format) under the interpretation given by this message class's definition
      * and returns a message object with the corresponding field values.
+     * @param options [Hash] options for the decoder
+     *  recursion_limit: set to maximum decoding depth for message (default is 100)
      */
-    @JRubyMethod(meta = true)
-    public static IRubyObject decode(ThreadContext context, IRubyObject recv, IRubyObject data) {
+    @JRubyMethod(required = 1, optional = 1, meta = true)
+    public static IRubyObject decode(ThreadContext context, IRubyObject recv, IRubyObject[] args) {
+        IRubyObject data = args[0];
         byte[] bin = data.convertToString().getBytes();
+        CodedInputStream input = CodedInputStream.newInstance(bin);
         RubyMessage ret = (RubyMessage) ((RubyClass) recv).newInstance(context, Block.NULL_BLOCK);
+
+        if (args.length == 2) {
+            if (!(args[1] instanceof RubyHash)) {
+                throw context.runtime.newArgumentError("Expected hash arguments.");
+            }
+
+            IRubyObject recursionLimit = ((RubyHash) args[1]).fastARef(context.runtime.newSymbol("recursion_limit"));
+            if (recursionLimit != null) {
+                input.setRecursionLimit(((RubyNumeric) recursionLimit).getIntValue());
+            }
+        }
+
         try {
-            ret.builder.mergeFrom(bin);
-        } catch (InvalidProtocolBufferException e) {
+            ret.builder.mergeFrom(input);
+        } catch (Exception e) {
             throw RaiseException.from(context.runtime, (RubyClass) context.runtime.getClassFromPath("Google::Protobuf::ParseError"), e.getMessage());
         }
 
@@ -541,7 +570,7 @@ public class RubyMessage extends RubyObject {
         printer = printer.usingTypeRegistry(JsonFormat.TypeRegistry.newBuilder().add(message.descriptor).build());
 
         try {
-            result = printer.print(message.build(context));
+            result = printer.print(message.build(context, 0, SINK_MAXIMUM_NESTING));
         } catch (InvalidProtocolBufferException e) {
             throw runtime.newRuntimeError(e.getMessage());
         } catch (IllegalArgumentException e) {
@@ -635,13 +664,9 @@ public class RubyMessage extends RubyObject {
         return ret;
     }
 
-    protected DynamicMessage build(ThreadContext context) {
-        return build(context, 0);
-    }
-
-    protected DynamicMessage build(ThreadContext context, int depth) {
-        if (depth > SINK_MAXIMUM_NESTING) {
-            throw context.runtime.newRuntimeError("Maximum recursion depth exceeded during encoding.");
+    protected DynamicMessage build(ThreadContext context, int depth, int recursionLimit) {
+        if (depth >= recursionLimit) {
+            throw context.runtime.newRuntimeError("Recursion limit exceeded during encoding.");
         }
 
         // Handle the typical case where the fields.keySet contain the fieldDescriptors
@@ -651,7 +676,7 @@ public class RubyMessage extends RubyObject {
             if (value instanceof RubyMap) {
                 builder.clearField(fieldDescriptor);
                 RubyDescriptor mapDescriptor = (RubyDescriptor) getDescriptorForField(context, fieldDescriptor);
-                for (DynamicMessage kv : ((RubyMap) value).build(context, mapDescriptor, depth)) {
+                for (DynamicMessage kv : ((RubyMap) value).build(context, mapDescriptor, depth, recursionLimit)) {
                     builder.addRepeatedField(fieldDescriptor, kv);
                 }
 
@@ -660,7 +685,7 @@ public class RubyMessage extends RubyObject {
 
                 builder.clearField(fieldDescriptor);
                 for (int i = 0; i < repeatedField.size(); i++) {
-                    Object item = convert(context, fieldDescriptor, repeatedField.get(i), depth,
+                    Object item = convert(context, fieldDescriptor, repeatedField.get(i), depth, recursionLimit,
                         /*isDefaultValueForBytes*/ false);
                     builder.addRepeatedField(fieldDescriptor, item);
                 }
@@ -682,7 +707,7 @@ public class RubyMessage extends RubyObject {
                     fieldDescriptor.getFullName().equals("google.protobuf.FieldDescriptorProto.default_value")) {
                     isDefaultStringForBytes = true;
                 }
-                builder.setField(fieldDescriptor, convert(context, fieldDescriptor, value, depth, isDefaultStringForBytes));
+                builder.setField(fieldDescriptor, convert(context, fieldDescriptor, value, depth, recursionLimit, isDefaultStringForBytes));
             }
         }
 
@@ -702,7 +727,7 @@ public class RubyMessage extends RubyObject {
                 builder.clearField(fieldDescriptor);
                 RubyDescriptor mapDescriptor = (RubyDescriptor) getDescriptorForField(context,
                     fieldDescriptor);
-                for (DynamicMessage kv : ((RubyMap) value).build(context, mapDescriptor, depth)) {
+                for (DynamicMessage kv : ((RubyMap) value).build(context, mapDescriptor, depth, recursionLimit)) {
                     builder.addRepeatedField(fieldDescriptor, kv);
                 }
             }
@@ -814,7 +839,8 @@ public class RubyMessage extends RubyObject {
     // convert a ruby object to protobuf type, skip type check since it is checked on the way in
     private Object convert(ThreadContext context,
                            FieldDescriptor fieldDescriptor,
-                           IRubyObject value, int depth, boolean isDefaultStringForBytes) {
+                           IRubyObject value, int depth, int recursionLimit,
+                           boolean isDefaultStringForBytes) {
         Object val = null;
         switch (fieldDescriptor.getType()) {
             case INT32:
@@ -855,7 +881,7 @@ public class RubyMessage extends RubyObject {
                 }
                 break;
             case MESSAGE:
-                val = ((RubyMessage) value).build(context, depth + 1);
+                val = ((RubyMessage) value).build(context, depth + 1, recursionLimit);
                 break;
             case ENUM:
                 EnumDescriptor enumDescriptor = fieldDescriptor.getEnumType();
@@ -1214,7 +1240,7 @@ public class RubyMessage extends RubyObject {
     private static final String CONST_SUFFIX = "_const";
     private static final String HAS_PREFIX = "has_";
     private static final String QUESTION_MARK = "?";
-    private static final int SINK_MAXIMUM_NESTING = 63;
+    private static final int SINK_MAXIMUM_NESTING = 64;
 
     private Descriptor descriptor;
     private DynamicMessage.Builder builder;

ruby/tests/common_tests.rb

@@ -1245,7 +1245,7 @@ module CommonTests
     struct = struct_from_ruby(JSON.parse(json))
     assert_equal json, struct.to_json
 
-    assert_raise(RuntimeError, "Maximum recursion depth exceeded during encoding") do
+    assert_raise(RuntimeError, "Recursion limit exceeded during encoding") do
       struct = Google::Protobuf::Struct.new
       struct.fields["foobar"] = Google::Protobuf::Value.new(struct_value: struct)
       Google::Protobuf::Struct.encode(struct)

ruby/tests/encode_decode_test.rb

@@ -101,4 +101,55 @@ class EncodeDecodeTest < Test::Unit::TestCase
     assert_match json, "{\"CustomJsonName\":42}"
   end
 
+  def test_decode_depth_limit
+    msg = A::B::C::TestMessage.new(
+      optional_msg: A::B::C::TestMessage.new(
+        optional_msg: A::B::C::TestMessage.new(
+          optional_msg: A::B::C::TestMessage.new(
+            optional_msg: A::B::C::TestMessage.new(
+              optional_msg: A::B::C::TestMessage.new(
+              )
+            )
+          )
+        )
+      )
+    )
+    msg_encoded = A::B::C::TestMessage.encode(msg)
+    msg_out = A::B::C::TestMessage.decode(msg_encoded)
+    assert_match msg.to_json, msg_out.to_json
+
+    assert_raise Google::Protobuf::ParseError do
+      A::B::C::TestMessage.decode(msg_encoded, { recursion_limit: 4 })
+    end
+
+    msg_out = A::B::C::TestMessage.decode(msg_encoded, { recursion_limit: 5 })
+    assert_match msg.to_json, msg_out.to_json
+  end
+
+  def test_encode_depth_limit
+    msg = A::B::C::TestMessage.new(
+      optional_msg: A::B::C::TestMessage.new(
+        optional_msg: A::B::C::TestMessage.new(
+          optional_msg: A::B::C::TestMessage.new(
+            optional_msg: A::B::C::TestMessage.new(
+              optional_msg: A::B::C::TestMessage.new(
+              )
+            )
+          )
+        )
+      )
+    )
+    msg_encoded = A::B::C::TestMessage.encode(msg)
+    msg_out = A::B::C::TestMessage.decode(msg_encoded)
+    assert_match msg.to_json, msg_out.to_json
+
+    assert_raise RuntimeError do
+      A::B::C::TestMessage.encode(msg, { recursion_limit: 5 })
+    end
+
+    msg_encoded = A::B::C::TestMessage.encode(msg, { recursion_limit: 6 })
+    msg_out = A::B::C::TestMessage.decode(msg_encoded)
+    assert_match msg.to_json, msg_out.to_json
+  end
+
 end

src/google/protobuf/any.cc

@@ -49,10 +49,8 @@ bool AnyMetadata::PackFrom(Arena* arena, const Message& message) {
 bool AnyMetadata::PackFrom(Arena* arena, const Message& message,
                            StringPiece type_url_prefix) {
   type_url_->Set(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyString(),
       GetTypeUrl(message.GetDescriptor()->full_name(), type_url_prefix), arena);
-  return message.SerializeToString(
-      value_->Mutable(ArenaStringPtr::EmptyDefault{}, arena));
+  return message.SerializeToString(value_->Mutable(arena));
 }
 
 bool AnyMetadata::UnpackTo(Message* message) const {

src/google/protobuf/any.pb.cc

@@ -119,18 +119,18 @@ Any::Any(const Any& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   type_url_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    type_url_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_type_url().empty()) {
-    type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_type_url(), 
+    type_url_.Set(from._internal_type_url(), 
       GetArenaForAllocation());
   }
   value_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    value_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_value().empty()) {
-    value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_value(), 
+    value_.Set(from._internal_value(), 
       GetArenaForAllocation());
   }
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Any)
@@ -139,11 +139,11 @@ Any::Any(const Any& from)
 inline void Any::SharedCtor() {
 type_url_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  type_url_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 value_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  value_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 }
 
@@ -158,8 +158,8 @@ Any::~Any() {
 
 inline void Any::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  type_url_.Destroy();
+  value_.Destroy();
 }
 
 void Any::SetCachedSize(int size) const {
@@ -325,12 +325,10 @@ void Any::InternalSwap(Any* other) {
   auto* rhs_arena = other->GetArenaForAllocation();
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &type_url_, lhs_arena,
       &other->type_url_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &value_, lhs_arena,
       &other->value_, rhs_arena
   );

src/google/protobuf/any.pb.h

@@ -275,7 +275,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Any::set_type_url(ArgT0&& arg0, ArgT... args) {
  
- type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ type_url_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Any.type_url)
 }
 inline std::string* Any::mutable_type_url() {
@@ -288,15 +288,15 @@ inline const std::string& Any::_internal_type_url() const {
 }
 inline void Any::_internal_set_type_url(const std::string& value) {
   
-  type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  type_url_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Any::_internal_mutable_type_url() {
   
-  return type_url_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return type_url_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Any::release_type_url() {
   // @@protoc_insertion_point(field_release:google.protobuf.Any.type_url)
-  return type_url_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return type_url_.Release();
 }
 inline void Any::set_allocated_type_url(std::string* type_url) {
   if (type_url != nullptr) {
@@ -304,11 +304,10 @@ inline void Any::set_allocated_type_url(std::string* type_url) {
   } else {
     
   }
-  type_url_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), type_url,
-      GetArenaForAllocation());
+  type_url_.SetAllocated(type_url, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (type_url_.IsDefault()) {
-    type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    type_url_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Any.type_url)
@@ -326,7 +325,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Any::set_value(ArgT0&& arg0, ArgT... args) {
  
- value_.SetBytes(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ value_.SetBytes(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Any.value)
 }
 inline std::string* Any::mutable_value() {
@@ -339,15 +338,15 @@ inline const std::string& Any::_internal_value() const {
 }
 inline void Any::_internal_set_value(const std::string& value) {
   
-  value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  value_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Any::_internal_mutable_value() {
   
-  return value_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return value_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Any::release_value() {
   // @@protoc_insertion_point(field_release:google.protobuf.Any.value)
-  return value_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return value_.Release();
 }
 inline void Any::set_allocated_value(std::string* value) {
   if (value != nullptr) {
@@ -355,11 +354,10 @@ inline void Any::set_allocated_value(std::string* value) {
   } else {
     
   }
-  value_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), value,
-      GetArenaForAllocation());
+  value_.SetAllocated(value, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (value_.IsDefault()) {
-    value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    value_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Any.value)

src/google/protobuf/any_lite.cc

@@ -55,10 +55,8 @@ const char kTypeGoogleProdComPrefix[] = "type.googleprod.com/";
 bool AnyMetadata::InternalPackFrom(Arena* arena, const MessageLite& message,
                                    StringPiece type_url_prefix,
                                    StringPiece type_name) {
-  type_url_->Set(&::google::protobuf::internal::GetEmptyString(),
-                 GetTypeUrl(type_name, type_url_prefix), arena);
-  return message.SerializeToString(
-      value_->Mutable(ArenaStringPtr::EmptyDefault{}, arena));
+  type_url_->Set(GetTypeUrl(type_name, type_url_prefix), arena);
+  return message.SerializeToString(value_->Mutable(arena));
 }
 
 bool AnyMetadata::InternalUnpackTo(StringPiece type_name,

src/google/protobuf/api.pb.cc

@@ -204,18 +204,18 @@ Api::Api(const Api& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_name().empty()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   version_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    version_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    version_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_version().empty()) {
-    version_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_version(), 
+    version_.Set(from._internal_version(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_source_context()) {
@@ -230,11 +230,11 @@ Api::Api(const Api& from)
 inline void Api::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 version_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  version_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  version_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&source_context_) - reinterpret_cast<char*>(this)),
@@ -253,8 +253,8 @@ Api::~Api() {
 
 inline void Api::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  version_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  version_.Destroy();
   if (this != internal_default_instance()) delete source_context_;
 }
 
@@ -574,12 +574,10 @@ void Api::InternalSwap(Api* other) {
   options_.InternalSwap(&other->options_);
   mixins_.InternalSwap(&other->mixins_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &version_, lhs_arena,
       &other->version_, rhs_arena
   );
@@ -619,26 +617,26 @@ Method::Method(const Method& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_name().empty()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   request_type_url_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    request_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    request_type_url_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_request_type_url().empty()) {
-    request_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_request_type_url(), 
+    request_type_url_.Set(from._internal_request_type_url(), 
       GetArenaForAllocation());
   }
   response_type_url_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    response_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    response_type_url_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_response_type_url().empty()) {
-    response_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_response_type_url(), 
+    response_type_url_.Set(from._internal_response_type_url(), 
       GetArenaForAllocation());
   }
   ::memcpy(&request_streaming_, &from.request_streaming_,
@@ -650,15 +648,15 @@ Method::Method(const Method& from)
 inline void Method::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 request_type_url_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  request_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  request_type_url_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 response_type_url_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  response_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  response_type_url_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&request_streaming_) - reinterpret_cast<char*>(this)),
@@ -677,9 +675,9 @@ Method::~Method() {
 
 inline void Method::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  request_type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  response_type_url_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  request_type_url_.Destroy();
+  response_type_url_.Destroy();
 }
 
 void Method::SetCachedSize(int size) const {
@@ -984,17 +982,14 @@ void Method::InternalSwap(Method* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   options_.InternalSwap(&other->options_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &request_type_url_, lhs_arena,
       &other->request_type_url_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &response_type_url_, lhs_arena,
       &other->response_type_url_, rhs_arena
   );
@@ -1029,18 +1024,18 @@ Mixin::Mixin(const Mixin& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_name().empty()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   root_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    root_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    root_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (!from._internal_root().empty()) {
-    root_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_root(), 
+    root_.Set(from._internal_root(), 
       GetArenaForAllocation());
   }
   // @@protoc_insertion_point(copy_constructor:google.protobuf.Mixin)
@@ -1049,11 +1044,11 @@ Mixin::Mixin(const Mixin& from)
 inline void Mixin::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 root_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  root_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  root_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 }
 
@@ -1068,8 +1063,8 @@ Mixin::~Mixin() {
 
 inline void Mixin::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  root_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  root_.Destroy();
 }
 
 void Mixin::SetCachedSize(int size) const {
@@ -1240,12 +1235,10 @@ void Mixin::InternalSwap(Mixin* other) {
   auto* rhs_arena = other->GetArenaForAllocation();
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &root_, lhs_arena,
       &other->root_, rhs_arena
   );

src/google/protobuf/api.pb.h

@@ -739,7 +739,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Api::set_name(ArgT0&& arg0, ArgT... args) {
  
- name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ name_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Api.name)
 }
 inline std::string* Api::mutable_name() {
@@ -752,15 +752,15 @@ inline const std::string& Api::_internal_name() const {
 }
 inline void Api::_internal_set_name(const std::string& value) {
   
-  name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  name_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Api::_internal_mutable_name() {
   
-  return name_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return name_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Api::release_name() {
   // @@protoc_insertion_point(field_release:google.protobuf.Api.name)
-  return name_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return name_.Release();
 }
 inline void Api::set_allocated_name(std::string* name) {
   if (name != nullptr) {
@@ -768,11 +768,10 @@ inline void Api::set_allocated_name(std::string* name) {
   } else {
     
   }
-  name_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), name,
-      GetArenaForAllocation());
+  name_.SetAllocated(name, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (name_.IsDefault()) {
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Api.name)
@@ -867,7 +866,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Api::set_version(ArgT0&& arg0, ArgT... args) {
  
- version_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ version_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Api.version)
 }
 inline std::string* Api::mutable_version() {
@@ -880,15 +879,15 @@ inline const std::string& Api::_internal_version() const {
 }
 inline void Api::_internal_set_version(const std::string& value) {
   
-  version_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  version_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Api::_internal_mutable_version() {
   
-  return version_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return version_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Api::release_version() {
   // @@protoc_insertion_point(field_release:google.protobuf.Api.version)
-  return version_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return version_.Release();
 }
 inline void Api::set_allocated_version(std::string* version) {
   if (version != nullptr) {
@@ -896,11 +895,10 @@ inline void Api::set_allocated_version(std::string* version) {
   } else {
     
   }
-  version_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), version,
-      GetArenaForAllocation());
+  version_.SetAllocated(version, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (version_.IsDefault()) {
-    version_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    version_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Api.version)
@@ -977,8 +975,7 @@ inline void Api::set_allocated_source_context(::PROTOBUF_NAMESPACE_ID::SourceCon
   }
   if (source_context) {
     ::PROTOBUF_NAMESPACE_ID::Arena* submessage_arena =
-        ::PROTOBUF_NAMESPACE_ID::Arena::InternalHelper<
-            ::PROTOBUF_NAMESPACE_ID::MessageLite>::GetOwningArena(
+        ::PROTOBUF_NAMESPACE_ID::Arena::InternalGetOwningArena(
                 reinterpret_cast<::PROTOBUF_NAMESPACE_ID::MessageLite*>(source_context));
     if (message_arena != submessage_arena) {
       source_context = ::PROTOBUF_NAMESPACE_ID::internal::GetOwnedMessage(
@@ -1068,7 +1065,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Method::set_name(ArgT0&& arg0, ArgT... args) {
  
- name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ name_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Method.name)
 }
 inline std::string* Method::mutable_name() {
@@ -1081,15 +1078,15 @@ inline const std::string& Method::_internal_name() const {
 }
 inline void Method::_internal_set_name(const std::string& value) {
   
-  name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  name_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Method::_internal_mutable_name() {
   
-  return name_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return name_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Method::release_name() {
   // @@protoc_insertion_point(field_release:google.protobuf.Method.name)
-  return name_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return name_.Release();
 }
 inline void Method::set_allocated_name(std::string* name) {
   if (name != nullptr) {
@@ -1097,11 +1094,10 @@ inline void Method::set_allocated_name(std::string* name) {
   } else {
     
   }
-  name_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), name,
-      GetArenaForAllocation());
+  name_.SetAllocated(name, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (name_.IsDefault()) {
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Method.name)
@@ -1119,7 +1115,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Method::set_request_type_url(ArgT0&& arg0, ArgT... args) {
  
- request_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ request_type_url_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Method.request_type_url)
 }
 inline std::string* Method::mutable_request_type_url() {
@@ -1132,15 +1128,15 @@ inline const std::string& Method::_internal_request_type_url() const {
 }
 inline void Method::_internal_set_request_type_url(const std::string& value) {
   
-  request_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  request_type_url_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Method::_internal_mutable_request_type_url() {
   
-  return request_type_url_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return request_type_url_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Method::release_request_type_url() {
   // @@protoc_insertion_point(field_release:google.protobuf.Method.request_type_url)
-  return request_type_url_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return request_type_url_.Release();
 }
 inline void Method::set_allocated_request_type_url(std::string* request_type_url) {
   if (request_type_url != nullptr) {
@@ -1148,11 +1144,10 @@ inline void Method::set_allocated_request_type_url(std::string* request_type_url
   } else {
     
   }
-  request_type_url_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), request_type_url,
-      GetArenaForAllocation());
+  request_type_url_.SetAllocated(request_type_url, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (request_type_url_.IsDefault()) {
-    request_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    request_type_url_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Method.request_type_url)
@@ -1190,7 +1185,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Method::set_response_type_url(ArgT0&& arg0, ArgT... args) {
  
- response_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ response_type_url_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Method.response_type_url)
 }
 inline std::string* Method::mutable_response_type_url() {
@@ -1203,15 +1198,15 @@ inline const std::string& Method::_internal_response_type_url() const {
 }
 inline void Method::_internal_set_response_type_url(const std::string& value) {
   
-  response_type_url_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  response_type_url_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Method::_internal_mutable_response_type_url() {
   
-  return response_type_url_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return response_type_url_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Method::release_response_type_url() {
   // @@protoc_insertion_point(field_release:google.protobuf.Method.response_type_url)
-  return response_type_url_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return response_type_url_.Release();
 }
 inline void Method::set_allocated_response_type_url(std::string* response_type_url) {
   if (response_type_url != nullptr) {
@@ -1219,11 +1214,10 @@ inline void Method::set_allocated_response_type_url(std::string* response_type_u
   } else {
     
   }
-  response_type_url_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), response_type_url,
-      GetArenaForAllocation());
+  response_type_url_.SetAllocated(response_type_url, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (response_type_url_.IsDefault()) {
-    response_type_url_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    response_type_url_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Method.response_type_url)
@@ -1322,7 +1316,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Mixin::set_name(ArgT0&& arg0, ArgT... args) {
  
- name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ name_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Mixin.name)
 }
 inline std::string* Mixin::mutable_name() {
@@ -1335,15 +1329,15 @@ inline const std::string& Mixin::_internal_name() const {
 }
 inline void Mixin::_internal_set_name(const std::string& value) {
   
-  name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  name_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Mixin::_internal_mutable_name() {
   
-  return name_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return name_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Mixin::release_name() {
   // @@protoc_insertion_point(field_release:google.protobuf.Mixin.name)
-  return name_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return name_.Release();
 }
 inline void Mixin::set_allocated_name(std::string* name) {
   if (name != nullptr) {
@@ -1351,11 +1345,10 @@ inline void Mixin::set_allocated_name(std::string* name) {
   } else {
     
   }
-  name_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), name,
-      GetArenaForAllocation());
+  name_.SetAllocated(name, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (name_.IsDefault()) {
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Mixin.name)
@@ -1373,7 +1366,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Mixin::set_root(ArgT0&& arg0, ArgT... args) {
  
- root_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ root_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.Mixin.root)
 }
 inline std::string* Mixin::mutable_root() {
@@ -1386,15 +1379,15 @@ inline const std::string& Mixin::_internal_root() const {
 }
 inline void Mixin::_internal_set_root(const std::string& value) {
   
-  root_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  root_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Mixin::_internal_mutable_root() {
   
-  return root_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return root_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Mixin::release_root() {
   // @@protoc_insertion_point(field_release:google.protobuf.Mixin.root)
-  return root_.Release(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  return root_.Release();
 }
 inline void Mixin::set_allocated_root(std::string* root) {
   if (root != nullptr) {
@@ -1402,11 +1395,10 @@ inline void Mixin::set_allocated_root(std::string* root) {
   } else {
     
   }
-  root_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), root,
-      GetArenaForAllocation());
+  root_.SetAllocated(root, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (root_.IsDefault()) {
-    root_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    root_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.Mixin.root)

src/google/protobuf/arena.h

@@ -410,27 +410,10 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
 
   template <typename T>
   class InternalHelper {
-   public:
+   private:
     // Provides access to protected GetOwningArena to generated messages.
     static Arena* GetOwningArena(const T* p) { return p->GetOwningArena(); }
 
-    // Provides access to protected GetArenaForAllocation to generated messages.
-    static Arena* GetArenaForAllocation(const T* p) {
-      return GetArenaForAllocationInternal(
-          p, std::is_convertible<T*, MessageLite*>());
-    }
-
-    // Creates message-owned arena.
-    static Arena* CreateMessageOwnedArena() {
-      return new Arena(internal::MessageOwned{});
-    }
-
-    // Checks whether the given arena is message-owned.
-    static bool IsMessageOwnedArena(Arena* arena) {
-      return arena->IsMessageOwned();
-    }
-
-   private:
     static Arena* GetArenaForAllocationInternal(
         const T* p, std::true_type /*is_derived_from<MessageLite>*/) {
       return p->GetArenaForAllocation();
@@ -513,6 +496,29 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     friend class TestUtil::ReflectionTester;
   };
 
+  // Provides access to protected GetOwningArena to generated messages.  For
+  // internal use only.
+  template <typename T>
+  static Arena* InternalGetOwningArena(const T* p) {
+    return InternalHelper<T>::GetOwningArena(p);
+  }
+
+  // Provides access to protected GetArenaForAllocation to generated messages.
+  // For internal use only.
+  template <typename T>
+  static Arena* InternalGetArenaForAllocation(const T* p) {
+    return InternalHelper<T>::GetArenaForAllocationInternal(
+        p, std::is_convertible<T*, MessageLite*>());
+  }
+
+  // Creates message-owned arena.  For internal use only.
+  static Arena* InternalCreateMessageOwnedArena() {
+    return new Arena(internal::MessageOwned{});
+  }
+
+  // Checks whether this arena is message-owned.  For internal use only.
+  bool InternalIsMessageOwnedArena() { return IsMessageOwned(); }
+
   // Helper typetraits that indicates support for arenas in a type T at compile
   // time. This is public only to allow construction of higher-level templated
   // utilities.

src/google/protobuf/arena_unittest.cc

@@ -547,13 +547,11 @@ TEST(ArenaTest, UnsafeArenaSwap) {
 TEST(ArenaTest, GetOwningArena) {
   Arena arena;
   auto* m1 = Arena::CreateMessage<TestAllTypes>(&arena);
-  EXPECT_EQ(Arena::InternalHelper<TestAllTypes>::GetOwningArena(m1), &arena);
-  EXPECT_EQ(
-      &arena,
-      Arena::InternalHelper<RepeatedPtrField<ForeignMessage>>::GetOwningArena(
+  EXPECT_EQ(Arena::InternalGetOwningArena(m1), &arena);
+  EXPECT_EQ(&arena, Arena::InternalGetOwningArena(
                         m1->mutable_repeated_foreign_message()));
-  EXPECT_EQ(&arena, Arena::InternalHelper<RepeatedField<int>>::GetOwningArena(
-                        m1->mutable_repeated_int32()));
+  EXPECT_EQ(&arena,
+            Arena::InternalGetOwningArena(m1->mutable_repeated_int32()));
 }
 
 TEST(ArenaTest, SwapBetweenArenasUsingReflection) {

src/google/protobuf/arenastring.cc

@@ -57,6 +57,8 @@ namespace  {
 // - alignof(std::string)
 #ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
 constexpr size_t kNewAlign = __STDCPP_DEFAULT_NEW_ALIGNMENT__;
+#elif (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
+constexpr size_t kNewAlign = alignof(::max_align_t);
 #else
 constexpr size_t kNewAlign = alignof(std::max_align_t);
 #endif
@@ -110,13 +112,7 @@ std::string* ArenaStringPtr::SetAndReturnNewString() {
   return new_string;
 }
 
-void ArenaStringPtr::DestroyNoArenaSlowPath() {
-  GOOGLE_DCHECK(tagged_ptr_.IsAllocated());
-  delete UnsafeMutablePointer();
-}
-
-void ArenaStringPtr::Set(const std::string*, ConstStringParam value,
-                         ::google::protobuf::Arena* arena) {
+void ArenaStringPtr::Set(ConstStringParam value, Arena* arena) {
   if (IsDefault()) {
     // If we're not on an arena, skip straight to a true string to avoid
     // possible copy cost later.
@@ -126,8 +122,8 @@ void ArenaStringPtr::Set(const std::string*, ConstStringParam value,
     UnsafeMutablePointer()->assign(value.data(), value.length());
   }
 }
-void ArenaStringPtr::Set(const std::string*, std::string&& value,
-                         ::google::protobuf::Arena* arena) {
+
+void ArenaStringPtr::Set(std::string&& value, Arena* arena) {
   if (IsDefault()) {
     NewString(arena, std::move(value));
   } else if (IsFixedSizeArena()) {
@@ -140,47 +136,26 @@ void ArenaStringPtr::Set(const std::string*, std::string&& value,
   }
 }
 
-void ArenaStringPtr::Set(EmptyDefault, ConstStringParam value,
-                         ::google::protobuf::Arena* arena) {
-  Set(&GetEmptyStringAlreadyInited(), value, arena);
-}
-
-void ArenaStringPtr::Set(EmptyDefault, std::string&& value,
-                         ::google::protobuf::Arena* arena) {
-  Set(&GetEmptyStringAlreadyInited(), std::move(value), arena);
-}
-
-void ArenaStringPtr::Set(NonEmptyDefault, ConstStringParam value,
-                         ::google::protobuf::Arena* arena) {
-  Set(nullptr, value, arena);
-}
-
-void ArenaStringPtr::Set(NonEmptyDefault, std::string&& value,
-                         ::google::protobuf::Arena* arena) {
-  Set(nullptr, std::move(value), arena);
-}
-
-std::string* ArenaStringPtr::Mutable(EmptyDefault, ::google::protobuf::Arena* arena) {
-  if (!IsFixedSizeArena() && !IsDefault()) {
-    return UnsafeMutablePointer();
+std::string* ArenaStringPtr::Mutable(Arena* arena) {
+  if (tagged_ptr_.IsMutable()) {
+    return tagged_ptr_.Get();
   } else {
     return MutableSlow(arena);
   }
 }
 
 std::string* ArenaStringPtr::Mutable(const LazyString& default_value,
-                                     ::google::protobuf::Arena* arena) {
-  if (!IsFixedSizeArena() && !IsDefault()) {
-    return UnsafeMutablePointer();
+                                     Arena* arena) {
+  if (tagged_ptr_.IsMutable()) {
+    return tagged_ptr_.Get();
   } else {
     return MutableSlow(arena, default_value);
   }
 }
 
-std::string* ArenaStringPtr::MutableNoCopy(const std::string*,
-                                           ::google::protobuf::Arena* arena) {
-  if (!IsFixedSizeArena() && !IsDefault()) {
-    return UnsafeMutablePointer();
+std::string* ArenaStringPtr::MutableNoCopy(Arena* arena) {
+  if (tagged_ptr_.IsMutable()) {
+    return tagged_ptr_.Get();
   } else {
     GOOGLE_DCHECK(IsDefault());
     // Allocate empty. The contents are not relevant.
@@ -195,45 +170,24 @@ std::string* ArenaStringPtr::MutableSlow(::google::protobuf::Arena* arena,
   return NewString(arena, lazy_default.get()...);
 }
 
-std::string* ArenaStringPtr::Release(const std::string* default_value,
-                                     ::google::protobuf::Arena* arena) {
-  if (IsDefault()) {
-    return nullptr;
-  } else {
-    return ReleaseNonDefault(default_value, arena);
-  }
-}
-
-std::string* ArenaStringPtr::ReleaseNonDefault(const std::string* default_value,
-                                               ::google::protobuf::Arena* arena) {
-  GOOGLE_DCHECK(!IsDefault());
+std::string* ArenaStringPtr::Release() {
+  if (IsDefault()) return nullptr;
 
-  if (!IsFixedSizeArena()) {
-    std::string* released;
-    if (arena != nullptr) {
-      released = new std::string;
-      released->swap(*UnsafeMutablePointer());
-    } else {
-      released = UnsafeMutablePointer();
+  std::string* released = tagged_ptr_.Get();
+  if (!tagged_ptr_.IsAllocated()) {
+    released = tagged_ptr_.IsMutable() ? new std::string(std::move(*released))
+                                       : new std::string(*released);
   }
-    tagged_ptr_.SetDefault(default_value);
+  InitDefault();
   return released;
-  } else /* IsFixedSizeArena() */ {
-    GOOGLE_DCHECK(arena != nullptr);
-    std::string* released = new std::string(Get());
-    tagged_ptr_.SetDefault(default_value);
-    return released;
-  }
 }
 
-void ArenaStringPtr::SetAllocated(const std::string* default_value,
-                                  std::string* value, ::google::protobuf::Arena* arena) {
+void ArenaStringPtr::SetAllocated(std::string* value, Arena* arena) {
   // Release what we have first.
-  if (arena == nullptr && !IsDefault()) {
-    delete UnsafeMutablePointer();
-  }
+  Destroy();
+
   if (value == nullptr) {
-    tagged_ptr_.SetDefault(default_value);
+    InitDefault();
   } else {
 #ifndef NDEBUG
     // On debug builds, copy the string so the address differs.  delete will
@@ -247,23 +201,12 @@ void ArenaStringPtr::SetAllocated(const std::string* default_value,
   }
 }
 
-void ArenaStringPtr::Destroy(const std::string*, ::google::protobuf::Arena* arena) {
-  if (arena == nullptr) {
-    GOOGLE_DCHECK(!IsFixedSizeArena());
-    if (!IsDefault()) {
-      delete UnsafeMutablePointer();
-    }
+void ArenaStringPtr::Destroy() {
+  if (tagged_ptr_.IsAllocated()) {
+    delete tagged_ptr_.Get();
   }
 }
 
-void ArenaStringPtr::Destroy(EmptyDefault, ::google::protobuf::Arena* arena) {
-  Destroy(&GetEmptyStringAlreadyInited(), arena);
-}
-
-void ArenaStringPtr::Destroy(NonEmptyDefault, ::google::protobuf::Arena* arena) {
-  Destroy(nullptr, arena);
-}
-
 void ArenaStringPtr::ClearToEmpty() {
   if (IsDefault()) {
     // Already set to default -- do nothing.

src/google/protobuf/arenastring.h

@@ -187,7 +187,7 @@ class TaggedPtr {
   }
 
   inline T* TagAs(Type type, T* p) {
-    GOOGLE_DCHECK(type == kDefault || p != nullptr);
+    GOOGLE_DCHECK(p != nullptr);
     assert_aligned(p);
     ptr_ = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(p) | type);
     return p;
@@ -232,84 +232,84 @@ struct PROTOBUF_EXPORT ArenaStringPtr {
   struct EmptyDefault {};
   struct NonEmptyDefault {};
 
-  void Set(const std::string* default_value, ConstStringParam value,
-           ::google::protobuf::Arena* arena);
-  void Set(const std::string* default_value, std::string&& value,
-           ::google::protobuf::Arena* arena);
-  void Set(EmptyDefault, ConstStringParam value, ::google::protobuf::Arena* arena);
-  void Set(EmptyDefault, std::string&& value, ::google::protobuf::Arena* arena);
-  void Set(NonEmptyDefault, ConstStringParam value, ::google::protobuf::Arena* arena);
-  void Set(NonEmptyDefault, std::string&& value, ::google::protobuf::Arena* arena);
-  template <typename FirstParam>
-  void Set(FirstParam p1, const char* str, ::google::protobuf::Arena* arena) {
-    Set(p1, ConstStringParam(str), arena);
-  }
-  template <typename FirstParam>
-  void Set(FirstParam p1, const char* str, size_t size,
-           ::google::protobuf::Arena* arena) {
-    ConstStringParam sp{str, size};  // for string_view and `const string &`
-    Set(p1, sp, arena);
-  }
-  template <typename FirstParam, typename RefWrappedType>
-  void Set(FirstParam p1,
-           std::reference_wrapper<RefWrappedType> const_string_ref,
-           ::google::protobuf::Arena* arena) {
-    Set(p1, const_string_ref.get(), arena);
-  }
+  // Called from generated code / reflection runtime only. Resets value to point
+  // to a default string pointer, with the semantics that this ArenaStringPtr
+  // does not own the pointed-to memory. Disregards initial value of ptr_ (so
+  // this is the *ONLY* safe method to call after construction or when
+  // reinitializing after becoming the active field in a oneof union).
+  inline void InitDefault();
 
-  template <typename FirstParam, typename SecondParam>
-  void SetBytes(FirstParam p1, SecondParam&& p2, ::google::protobuf::Arena* arena) {
-    Set(p1, static_cast<SecondParam&&>(p2), arena);
-  }
-  template <typename FirstParam>
-  void SetBytes(FirstParam p1, const void* str, size_t size,
+  // Similar to `InitDefault` except that it allows the default value to be
+  // initialized to an externally owned string. This method is called from
+  // parsing code. `str` must not be null and outlive this instance.
+  inline void InitExternal(const std::string* str);
+
+  // Called from generated code / reflection runtime only. Resets the value of
+  // this instances to the heap allocated value in `str`. `str` must not be
+  // null. Invokes `arena->Own(str)` to transfer ownership into the arena if
+  // `arena` is not null, else, `str` will be owned by ArenaStringPtr. This
+  // function should only be used to initialize a ArenaStringPtr or on an
+  // instance known to not carry any heap allocated value.
+  inline void InitAllocated(std::string* str, Arena* arena);
+
+  void Set(ConstStringParam value, Arena* arena);
+  void Set(std::string&& value, Arena* arena);
+  void Set(const char* s, Arena* arena);
+  void Set(const char* s, size_t n, Arena* arena);
+
+  void SetBytes(ConstStringParam value, Arena* arena);
+  void SetBytes(std::string&& value, Arena* arena);
+  void SetBytes(const char* s, Arena* arena);
+  void SetBytes(const void* p, size_t n, Arena* arena);
+
+  template <typename RefWrappedType>
+  void Set(std::reference_wrapper<RefWrappedType> const_string_ref,
            ::google::protobuf::Arena* arena) {
-    // must work whether ConstStringParam is string_view or `const string &`
-    ConstStringParam sp{static_cast<const char*>(str), size};
-    Set(p1, sp, arena);
+    Set(const_string_ref.get(), arena);
   }
 
+  // Returns a mutable std::string reference.
+  // The version accepting a `LazyString` value is used in the generated code to
+  // initialize mutable copies for fields with a non-empty default where the
+  // default value is lazily initialized.
+  std::string* Mutable(Arena* arena);
+  std::string* Mutable(const LazyString& default_value, Arena* arena);
+
+  // Gets a mutable pointer with unspecified contents.
+  // This function is identical to Mutable(), except it is optimized for the
+  // case where the caller is not interested in the current contents. For
+  // example, if the current field is not mutable, it will re-initialize the
+  // value with an empty string rather than a (non-empty) default value.
+  // Likewise, if the current value is a fixed size arena string with contents,
+  // it will be initialized into an empty mutable arena string.
+  std::string* MutableNoCopy(Arena* arena);
+
   // Basic accessors.
   PROTOBUF_NDEBUG_INLINE const std::string& Get() const {
     // Unconditionally mask away the tag.
     return *tagged_ptr_.Get();
   }
-  PROTOBUF_NDEBUG_INLINE const std::string* GetPointer() const {
-    // Unconditionally mask away the tag.
+
+  // Returns a pointer to the stored contents for this instance.
+  // This method is for internal debugging and tracking purposes only.
+  PROTOBUF_NDEBUG_INLINE const std::string* UnsafeGetPointer() const
+      PROTOBUF_RETURNS_NONNULL {
     return tagged_ptr_.Get();
   }
 
-  // For fields with an empty default value.
-  std::string* Mutable(EmptyDefault, ::google::protobuf::Arena* arena);
-  // For fields with a non-empty default value.
-  std::string* Mutable(const LazyString& default_value, ::google::protobuf::Arena* arena);
-
   // Release returns a std::string* instance that is heap-allocated and is not
   // Own()'d by any arena. If the field is not set, this returns nullptr. The
-  // caller retains ownership. Clears this field back to nullptr state. Used to
-  // implement release_<field>() methods on generated classes.
-  PROTOBUF_NODISCARD std::string* Release(const std::string* default_value,
-                                          ::google::protobuf::Arena* arena);
-  PROTOBUF_NODISCARD std::string* ReleaseNonDefault(
-      const std::string* default_value, ::google::protobuf::Arena* arena);
+  // caller retains ownership. Clears this field back to the default state.
+  // Used to implement release_<field>() methods on generated classes.
+  PROTOBUF_NODISCARD std::string* Release();
 
   // Takes a std::string that is heap-allocated, and takes ownership. The
   // std::string's destructor is registered with the arena. Used to implement
   // set_allocated_<field> in generated classes.
-  void SetAllocated(const std::string* default_value, std::string* value,
-                    ::google::protobuf::Arena* arena);
-
-  // Swaps internal pointers. Arena-safety semantics: this is guarded by the
-  // logic in Swap()/UnsafeArenaSwap() at the message level, so this method is
-  // 'unsafe' if called directly.
-  inline PROTOBUF_NDEBUG_INLINE static void InternalSwap(
-      const std::string* default_value, ArenaStringPtr* rhs, Arena* rhs_arena,
-      ArenaStringPtr* lhs, Arena* lhs_arena);
+  void SetAllocated(std::string* value, Arena* arena);
 
   // Frees storage (if not on an arena).
-  void Destroy(const std::string* default_value, ::google::protobuf::Arena* arena);
-  void Destroy(EmptyDefault, ::google::protobuf::Arena* arena);
-  void Destroy(NonEmptyDefault, ::google::protobuf::Arena* arena);
+  void Destroy();
 
   // Clears content, but keeps allocated std::string, to avoid the overhead of
   // heap operations. After this returns, the content (as seen by the user) will
@@ -326,37 +326,109 @@ struct PROTOBUF_EXPORT ArenaStringPtr {
   // (as seen by the user) will always be equal to |default_value|.
   void ClearToDefault(const LazyString& default_value, ::google::protobuf::Arena* arena);
 
-  // Called from generated code / reflection runtime only. Resets value to point
-  // to a default string pointer, with the semantics that this ArenaStringPtr
-  // does not own the pointed-to memory. Disregards initial value of ptr_ (so
-  // this is the *ONLY* safe method to call after construction or when
-  // reinitializing after becoming the active field in a oneof union).
-  // This function allows an explicit default value other than the default
-  // global empty string. This is used in unit tests and by fields with
-  // explicit non-empty default string values using null defaults.
-  inline void InitDefault();
-  inline void InitDefault(const std::string* str);
+  // Swaps internal pointers. Arena-safety semantics: this is guarded by the
+  // logic in Swap()/UnsafeArenaSwap() at the message level, so this method is
+  // 'unsafe' if called directly.
+  inline PROTOBUF_NDEBUG_INLINE static void InternalSwap(ArenaStringPtr* rhs,
+                                                         Arena* rhs_arena,
+                                                         ArenaStringPtr* lhs,
+                                                         Arena* lhs_arena);
+
+  // --------------------------------------------------------
+  // Below functions will be removed in subsequent code change
+  // --------------------------------------------------------
+#ifdef DEPRECATED_METHODS_TO_BE_DELETED
+  PROTOBUF_NDEBUG_INLINE const std::string* GetPointer() const {
+    return UnsafeGetPointer();
+  }
 
-  // Called from generated code / reflection runtime only. Resets the value of
-  // this instances to the heap allocated value in `str`. `str` must not be
-  // null. Invokes `arena->Own(str)` to transfer ownership into the arena if
-  // `arena` is not null, else, `str` will be owned by ArenaStringPtr. This
-  // function should only be used to initialize a ArenaStringPtr or on an
-  // instance known to not carry any heap allocated value.
-  inline void InitAllocated(std::string* str, Arena* arena);
+  template <typename DefaultArg>
+  void Set(DefaultArg, ConstStringParam value, Arena* arena) {
+    return Set(value, arena);
+  }
+  template <typename DefaultArg>
+  void Set(DefaultArg, std::string&& value, Arena* arena) {
+    return Set(std::move(value), arena);
+  }
+  template <typename DefaultArg>
+  void Set(DefaultArg, const char* s, Arena* arena) {
+    return Set(ConstStringParam{s}, arena);
+  }
+  template <typename DefaultArg>
+  void Set(DefaultArg, const char* s, size_t n, Arena* arena) {
+    return Set(ConstStringParam{s, n}, arena);
+  }
 
-  // Returns a mutable pointer, but doesn't initialize the string to the
-  // default value.
-  std::string* MutableNoArenaNoDefault(const std::string* default_value);
+  void SetBytes(EmptyDefault, ConstStringParam value, Arena* arena) {
+    return Set(value, arena);
+  }
+  void SetBytes(NonEmptyDefault, ConstStringParam value, Arena* arena) {
+    return Set(value, arena);
+  }
+  void SetBytes(const std::string*, ConstStringParam value, Arena* arena) {
+    return Set(value, arena);
+  }
+  void SetBytes(EmptyDefault, std::string&& value, Arena* arena) {
+    return Set(std::move(value), arena);
+  }
+  void SetBytes(NonEmptyDefault, std::string&& value, Arena* arena) {
+    return Set(std::move(value), arena);
+  }
+  void SetBytes(const std::string*, std::string&& value, Arena* arena) {
+    return Set(std::move(value), arena);
+  }
+  void SetBytes(EmptyDefault, const char* s, Arena* arena) {
+    return Set(s, arena);
+  }
+  void SetBytes(NonEmptyDefault, const char* s, Arena* arena) {
+    return Set(s, arena);
+  }
+  void SetBytes(const std::string*, const char* s, Arena* arena) {
+    return Set(s, arena);
+  }
+  void SetBytes(EmptyDefault, const void* p, size_t n, Arena* arena) {
+    return SetBytes(p, n, arena);
+  }
+  void SetBytes(NonEmptyDefault, const void* p, size_t n, Arena* arena) {
+    return SetBytes(p, n, arena);
+  }
+  void SetBytes(const std::string*, const void* p, size_t n, Arena* arena) {
+    return SetBytes(p, n, arena);
+  }
+
+  std::string* Mutable(EmptyDefault, Arena* arena) { return Mutable(arena); }
+  std::string* MutableNoArenaNoDefault(const std::string*) {
+    return Mutable(nullptr);
+  }
+  std::string* MutableNoCopy(const std::string*, ::google::protobuf::Arena* arena) {
+    return MutableNoCopy(arena);
+  }
+
+  PROTOBUF_NODISCARD std::string* Release(const std::string*, Arena* arena) {
+    return Release();
+  }
+  PROTOBUF_NODISCARD std::string* ReleaseNonDefault(const std::string*,
+                                                    Arena* arena) {
+    return Release();
+  }
 
-  // Get a mutable pointer with unspecified contents.
-  // Similar to `MutableNoArenaNoDefault`, but also handles the arena case.
-  // If the value was donated, the contents are discarded.
-  std::string* MutableNoCopy(const std::string* default_value,
-                             ::google::protobuf::Arena* arena);
+  void SetAllocated(const std::string*, std::string* value, Arena* arena) {
+    SetAllocated(value, arena);
+  }
 
-  // Destroy the string. Assumes `arena == nullptr`.
-  void DestroyNoArena(const std::string* default_value);
+  void Destroy(const std::string*, ::google::protobuf::Arena* arena) { Destroy(); }
+  void Destroy(EmptyDefault, ::google::protobuf::Arena* arena) { Destroy(); }
+  void Destroy(NonEmptyDefault, ::google::protobuf::Arena* arena) { Destroy(); }
+  void DestroyNoArena(const std::string*) { Destroy(); }
+
+  inline PROTOBUF_NDEBUG_INLINE static void InternalSwap(const std::string*,
+                                                         ArenaStringPtr* rhs,
+                                                         Arena* rhs_arena,
+                                                         ArenaStringPtr* lhs,
+                                                         Arena* lhs_arena) {
+    InternalSwap(rhs, rhs_arena, lhs, lhs_arena);
+  }
+#endif  // DEPRECATED_METHODS_TO_BE_DELETED
 
   // Internal setter used only at parse time to directly set a donated string
   // value.
@@ -407,9 +479,6 @@ struct PROTOBUF_EXPORT ArenaStringPtr {
   // Sets value to a newly allocated string and returns it
   std::string* SetAndReturnNewString();
 
-  // Destroys the non-default string value out-of-line
-  void DestroyNoArenaSlowPath();
-
   friend class EpsCopyInputStream;
 };
 
@@ -417,7 +486,7 @@ inline void ArenaStringPtr::InitDefault() {
   tagged_ptr_ = TaggedPtr<std::string>(&fixed_address_empty_string);
 }
 
-inline void ArenaStringPtr::InitDefault(const std::string* str) {
+inline void ArenaStringPtr::InitExternal(const std::string* str) {
   tagged_ptr_.SetDefault(str);
 }
 
@@ -430,9 +499,32 @@ inline void ArenaStringPtr::InitAllocated(std::string* str, Arena* arena) {
   }
 }
 
+inline void ArenaStringPtr::Set(const char* s, Arena* arena) {
+  Set(ConstStringParam{s}, arena);
+}
+
+inline void ArenaStringPtr::Set(const char* s, size_t n, Arena* arena) {
+  Set(ConstStringParam{s, n}, arena);
+}
+
+inline void ArenaStringPtr::SetBytes(ConstStringParam value, Arena* arena) {
+  Set(value, arena);
+}
+
+inline void ArenaStringPtr::SetBytes(std::string&& value, Arena* arena) {
+  Set(std::move(value), arena);
+}
+
+inline void ArenaStringPtr::SetBytes(const char* s, Arena* arena) {
+  Set(s, arena);
+}
+
+inline void ArenaStringPtr::SetBytes(const void* p, size_t n, Arena* arena) {
+  Set(ConstStringParam{static_cast<const char*>(p), n}, arena);
+}
+
 // Make sure rhs_arena allocated rhs, and lhs_arena allocated lhs.
 inline PROTOBUF_NDEBUG_INLINE void ArenaStringPtr::InternalSwap(  //
-    const std::string*,                                           //
     ArenaStringPtr* rhs, Arena* rhs_arena,                        //
     ArenaStringPtr* lhs, Arena* lhs_arena) {
   // Silence unused variable warnings in release buildls.
@@ -466,28 +558,6 @@ inline void ArenaStringPtr::ClearNonDefaultToEmpty() {
   tagged_ptr_.Get()->clear();
 }
 
-inline std::string* ArenaStringPtr::MutableNoArenaNoDefault(
-    const std::string* /* default_value */) {
-  // VERY IMPORTANT for performance and code size: this will reduce to a member
-  // variable load, a pointer check (against |default_value|, in practice a
-  // static global) and a branch to the slowpath (which calls operator new and
-  // the ctor). DO NOT add any tagged-pointer operations here.
-  GOOGLE_DCHECK(!tagged_ptr_.IsArena());
-  if (IsDefault()) {
-    return SetAndReturnNewString();
-  } else {
-    return UnsafeMutablePointer();
-  }
-}
-
-inline void ArenaStringPtr::DestroyNoArena(
-    const std::string* /* default_value */) {
-  GOOGLE_DCHECK(!tagged_ptr_.IsArena());
-  if (!IsDefault()) {
-    DestroyNoArenaSlowPath();
-  }
-}
-
 inline std::string* ArenaStringPtr::UnsafeMutablePointer() {
   GOOGLE_DCHECK(tagged_ptr_.IsMutable());
   GOOGLE_DCHECK(tagged_ptr_.Get() != nullptr);

src/google/protobuf/arenastring_unittest.cc

@@ -34,6 +34,7 @@
 #include <cstdlib>
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include <google/protobuf/stubs/logging.h>
@@ -72,37 +73,36 @@ INSTANTIATE_TEST_SUITE_P(ArenaString, SingleArena, testing::Bool());
 TEST_P(SingleArena, GetSet) {
   auto arena = GetArena();
   ArenaStringPtr field;
-  field.InitDefault(empty_default);
+  field.InitDefault();
   EXPECT_EQ("", field.Get());
-  field.Set(empty_default, "Test short", arena.get());
+  field.Set("Test short", arena.get());
   EXPECT_EQ("Test short", field.Get());
-  field.Set(empty_default, "Test long long long long value", arena.get());
+  field.Set("Test long long long long value", arena.get());
   EXPECT_EQ("Test long long long long value", field.Get());
-  field.Set(empty_default, "", arena.get());
-  field.Destroy(empty_default, arena.get());
+  field.Set("", arena.get());
+  field.Destroy();
 }
 
 TEST_P(SingleArena, MutableAccessor) {
   auto arena = GetArena();
   ArenaStringPtr field;
-  const std::string* empty_default = &internal::GetEmptyString();
-  field.InitDefault(empty_default);
+  field.InitDefault();
 
-  std::string* mut = field.Mutable(EmptyDefault{}, arena.get());
-  EXPECT_EQ(mut, field.Mutable(EmptyDefault{}, arena.get()));
+  std::string* mut = field.Mutable(arena.get());
+  EXPECT_EQ(mut, field.Mutable(arena.get()));
   EXPECT_EQ(mut, &field.Get());
   EXPECT_NE(empty_default, mut);
   EXPECT_EQ("", *mut);
   *mut = "Test long long long long value";  // ensure string allocates storage
   EXPECT_EQ("Test long long long long value", field.Get());
-  field.Destroy(empty_default, arena.get());
+  field.Destroy();
 }
 
 TEST_P(SingleArena, NullDefault) {
   auto arena = GetArena();
 
   ArenaStringPtr field;
-  field.InitDefault(nullptr);
+  field.InitDefault();
   std::string* mut = field.Mutable(nonempty_default, arena.get());
   EXPECT_EQ(mut, field.Mutable(nonempty_default, arena.get()));
   EXPECT_EQ(mut, &field.Get());
@@ -110,7 +110,7 @@ TEST_P(SingleArena, NullDefault) {
   EXPECT_EQ("default", *mut);
   *mut = "Test long long long long value";  // ensure string allocates storage
   EXPECT_EQ("Test long long long long value", field.Get());
-  field.Destroy(nullptr, arena.get());
+  field.Destroy();
 }
 
 class DualArena : public testing::TestWithParam<std::tuple<bool, bool>> {
@@ -131,23 +131,22 @@ INSTANTIATE_TEST_SUITE_P(ArenaString, DualArena,
 TEST_P(DualArena, Swap) {
   auto lhs_arena = GetLhsArena();
   ArenaStringPtr lhs;
-  lhs.InitDefault(empty_default);
+  lhs.InitDefault();
   ArenaStringPtr rhs;
-  rhs.InitDefault(empty_default);
+  rhs.InitDefault();
 
   {
     auto rhs_arena = GetRhsArena();
-    lhs.Set(empty_default, "lhs value that has some heft", lhs_arena.get());
-    rhs.Set(empty_default, "rhs value that has some heft", rhs_arena.get());
-    ArenaStringPtr::InternalSwap(empty_default,          //
-                                 &lhs, lhs_arena.get(),  //
+    lhs.Set("lhs value that has some heft", lhs_arena.get());
+    rhs.Set("rhs value that has some heft", rhs_arena.get());
+    ArenaStringPtr::InternalSwap(&lhs, lhs_arena.get(),  //
                                  &rhs, rhs_arena.get());
     EXPECT_EQ("rhs value that has some heft", lhs.Get());
     EXPECT_EQ("lhs value that has some heft", rhs.Get());
-    lhs.Destroy(empty_default, rhs_arena.get());
+    lhs.Destroy();
   }
   EXPECT_EQ("lhs value that has some heft", rhs.Get());
-  rhs.Destroy(empty_default, lhs_arena.get());
+  rhs.Destroy();
 }
 
 

src/google/protobuf/compiler/cpp/cpp_enum_field.cc

@@ -91,7 +91,7 @@ void EnumFieldGenerator::GenerateInlineAccessorDefinitions(
   Formatter format(printer, variables_);
   format(
       "inline $type$ $classname$::_internal_$name$() const {\n"
-      "  return static_cast< $type$ >($name$_);\n"
+      "  return static_cast< $type$ >($field$);\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
       "$annotate_get$"
@@ -104,7 +104,7 @@ void EnumFieldGenerator::GenerateInlineAccessorDefinitions(
   }
   format(
       "  $set_hasbit$\n"
-      "  $name$_ = value;\n"
+      "  $field$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
       "  _internal_set_$name$(value);\n"
@@ -115,7 +115,7 @@ void EnumFieldGenerator::GenerateInlineAccessorDefinitions(
 
 void EnumFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_ = $default$;\n");
+  format("$field$ = $default$;\n");
 }
 
 void EnumFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
@@ -125,7 +125,7 @@ void EnumFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
 
 void EnumFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("swap($name$_, other->$name$_);\n");
+  format("swap($field$, other->$field$);\n");
 }
 
 void EnumFieldGenerator::GenerateConstructorCode(io::Printer* printer) const {
@@ -177,7 +177,7 @@ void EnumOneofFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline $type$ $classname$::_internal_$name$() const {\n"
       "  if (_internal_has_$name$()) {\n"
-      "    return static_cast< $type$ >($field_member$);\n"
+      "    return static_cast< $type$ >($field$);\n"
       "  }\n"
       "  return static_cast< $type$ >($default$);\n"
       "}\n"
@@ -195,7 +195,7 @@ void EnumOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
       "  }\n"
-      "  $field_member$ = value;\n"
+      "  $field$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
       "  _internal_set_$name$(value);\n"
@@ -206,7 +206,7 @@ void EnumOneofFieldGenerator::GenerateInlineAccessorDefinitions(
 
 void EnumOneofFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field_member$ = $default$;\n");
+  format("$field$ = $default$;\n");
 }
 
 void EnumOneofFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
@@ -264,7 +264,7 @@ void RepeatedEnumFieldGenerator::GenerateInlineAccessorDefinitions(
   Formatter format(printer, variables_);
   format(
       "inline $type$ $classname$::_internal_$name$(int index) const {\n"
-      "  return static_cast< $type$ >($name$_.Get(index));\n"
+      "  return static_cast< $type$ >($field$.Get(index));\n"
       "}\n"
       "inline $type$ $classname$::$name$(int index) const {\n"
       "$annotate_get$"
@@ -276,7 +276,7 @@ void RepeatedEnumFieldGenerator::GenerateInlineAccessorDefinitions(
     format("  assert($type$_IsValid(value));\n");
   }
   format(
-      "  $name$_.Set(index, value);\n"
+      "  $field$.Set(index, value);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
@@ -285,7 +285,7 @@ void RepeatedEnumFieldGenerator::GenerateInlineAccessorDefinitions(
     format("  assert($type$_IsValid(value));\n");
   }
   format(
-      "  $name$_.Add(value);\n"
+      "  $field$.Add(value);\n"
       "}\n"
       "inline void $classname$::add_$name$($type$ value) {\n"
       "  _internal_add_$name$(value);\n"
@@ -296,11 +296,11 @@ void RepeatedEnumFieldGenerator::GenerateInlineAccessorDefinitions(
       "$classname$::$name$() const {\n"
       "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
-      "  return $name$_;\n"
+      "  return $field$;\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedField<int>*\n"
       "$classname$::_internal_mutable_$name$() {\n"
-      "  return &$name$_;\n"
+      "  return &$field$;\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedField<int>*\n"
       "$classname$::mutable_$name$() {\n"
@@ -313,19 +313,19 @@ void RepeatedEnumFieldGenerator::GenerateInlineAccessorDefinitions(
 void RepeatedEnumFieldGenerator::GenerateClearingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.Clear();\n");
+  format("$field$.Clear();\n");
 }
 
 void RepeatedEnumFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.MergeFrom(from.$name$_);\n");
+  format("$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedEnumFieldGenerator::GenerateSwappingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.InternalSwap(&other->$name$_);\n");
+  format("$field$.InternalSwap(&other->$field$);\n");
 }
 
 void RepeatedEnumFieldGenerator::GenerateConstructorCode(
@@ -344,7 +344,7 @@ void RepeatedEnumFieldGenerator::GenerateSerializeWithCachedSizesToArray(
         "_$name$_cached_byte_size_.load(std::memory_order_relaxed);\n"
         "  if (byte_size > 0) {\n"
         "    target = stream->WriteEnumPacked(\n"
-        "        $number$, $name$_, byte_size, target);\n"
+        "        $number$, $field$, byte_size, target);\n"
         "  }\n"
         "}\n");
   } else {
@@ -375,6 +375,7 @@ void RepeatedEnumFieldGenerator::GenerateByteSize(io::Printer* printer) const {
     format(
         "if (data_size > 0) {\n"
         "  total_size += $tag_size$ +\n"
+        "    "
         "::_pbi::WireFormatLite::Int32Size(static_cast<$int32$>(data_size));\n"
         "}\n"
         "int cached_size = ::_pbi::ToCachedSize(data_size);\n"

src/google/protobuf/compiler/cpp/cpp_field.cc

@@ -81,7 +81,7 @@ std::string GenerateTemplateForOneofString(const FieldDescriptor* descriptor,
   std::string field_name = google::protobuf::compiler::cpp::FieldName(descriptor);
   std::string field_pointer =
       descriptor->options().ctype() == google::protobuf::FieldOptions::STRING
-          ? "$0.GetPointer()"
+          ? "$0.UnsafeGetPointer()"
           : "$0";
 
   if (descriptor->default_value_string().empty()) {
@@ -114,7 +114,7 @@ std::string GenerateTemplateForSingleString(const FieldDescriptor* descriptor,
 
   if (descriptor->options().ctype() == google::protobuf::FieldOptions::STRING) {
     return strings::Substitute(
-        "$0.IsDefault() ? &$1.get() : $0.GetPointer()", field_member,
+        "$0.IsDefault() ? &$1.get() : $0.UnsafeGetPointer()", field_member,
         MakeDefaultName(descriptor));
   }
 
@@ -241,7 +241,12 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
   (*variables)["number"] = StrCat(descriptor->number());
   (*variables)["classname"] = ClassName(FieldScope(descriptor), false);
   (*variables)["declared_type"] = DeclaredTypeMethodName(descriptor->type());
+  // TODO(b/218325252): convert all usages of "field_member" to "field" and
+  // remove this. The former may unnecessarily cause line breaks in protoc code.
+  // Note that the length of variables has no effect on the generated code. It
+  // only affects the readability of code template in protoc.
   (*variables)["field_member"] = FieldMemberName(descriptor);
+  (*variables)["field"] = FieldMemberName(descriptor);
 
   (*variables)["tag_size"] = StrCat(
       WireFormat::TagSize(descriptor->number(), descriptor->type()));

src/google/protobuf/compiler/cpp/cpp_generator.cc

@@ -82,6 +82,12 @@ bool CppGenerator::Generate(const FileDescriptor* file,
   // FOO_EXPORT is a macro which should expand to __declspec(dllexport) or
   // __declspec(dllimport) depending on what is being compiled.
   //
+  // If the proto_h option is passed to the compiler, we will generate all
+  // classes and enums so that they can be forward-declared from files that
+  // need them from imports.
+  //
+  // If the lite option is passed to the compiler, we will generate the
+  // current files and all transitive dependencies using the LITE runtime.
   Options file_options;
 
   file_options.opensource_runtime = opensource_runtime_;
@@ -111,6 +117,8 @@ bool CppGenerator::Generate(const FileDescriptor* file,
         file_options.num_cc_files =
             strto32(options[i].second.c_str(), nullptr, 10);
       }
+    } else if (options[i].first == "proto_h") {
+      file_options.proto_h = true;
     } else if (options[i].first == "annotate_accessor") {
       file_options.annotate_accessor = true;
     } else if (options[i].first == "inject_field_listener_events") {

src/google/protobuf/compiler/cpp/cpp_message.cc

@@ -1240,12 +1240,13 @@ void MessageGenerator::GenerateFieldAccessorDefinitions(io::Printer* printer) {
       } else {
         format(
             "inline int $classname$::_internal_$name$_size() const {\n"
-            "  return $name$_$1$.size();\n"
+            "  return $1$$2$.size();\n"
             "}\n"
             "inline int $classname$::$name$_size() const {\n"
             "$annotate_size$"
             "  return _internal_$name$_size();\n"
             "}\n",
+            FieldMemberName(field),
             IsImplicitWeakField(field, options_, scc_analyzer_) &&
                     field->message_type()
                 ? ".weak"
@@ -1391,8 +1392,7 @@ void MessageGenerator::GenerateClassDefinition(io::Printer* printer) {
   if (EnableMessageOwnedArena(descriptor_, options_)) {
     format(
         "inline $classname$() : $classname$("
-        "::$proto_ns$::Arena::InternalHelper<$classname$>::\n"
-        "    CreateMessageOwnedArena(), true) {}\n");
+        "::$proto_ns$::Arena::InternalCreateMessageOwnedArena(), true) {}\n");
   } else {
     format("inline $classname$() : $classname$(nullptr) {}\n");
   }

src/google/protobuf/compiler/cpp/cpp_message_field.cc

@@ -182,14 +182,13 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       // If we're not on an arena, free whatever we were holding before.
       // (If we are on arena, we can just forget the earlier pointer.)
       "  if (GetArenaForAllocation() == nullptr) {\n"
-      "    delete reinterpret_cast<::$proto_ns$::MessageLite*>($name$_);\n"
+      "    delete reinterpret_cast<::$proto_ns$::MessageLite*>($field$);\n"
       "  }\n");
   if (implicit_weak_field_) {
     format(
-        "  $name$_ = "
-        "reinterpret_cast<::$proto_ns$::MessageLite*>($name$);\n");
+        "  $field$ = reinterpret_cast<::$proto_ns$::MessageLite*>($name$);\n");
   } else {
-    format("  $name$_ = $name$;\n");
+    format("  $field$ = $name$;\n");
   }
   format(
       "  if ($name$) {\n"
@@ -207,7 +206,7 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "$annotate_release$"
       "  $clear_hasbit$\n"
       "  $type$* temp = $casted_member$;\n"
-      "  $name$_ = nullptr;\n"
+      "  $field$ = nullptr;\n"
       "#ifdef PROTOBUF_FORCE_COPY_IN_RELEASE\n"
       "  auto* old =  reinterpret_cast<::$proto_ns$::MessageLite*>(temp);\n"
       "  temp = ::$proto_ns$::internal::DuplicateIfNonNull(temp);\n"
@@ -225,7 +224,7 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "$type_reference_function$"
       "  $clear_hasbit$\n"
       "  $type$* temp = $casted_member$;\n"
-      "  $name$_ = nullptr;\n"
+      "  $field$ = nullptr;\n"
       "  return temp;\n"
       "}\n");
 
@@ -233,12 +232,12 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "inline $type$* $classname$::_internal_mutable_$name$() {\n"
       "$type_reference_function$"
       "  $set_hasbit$\n"
-      "  if ($name$_ == nullptr) {\n"
+      "  if ($field$ == nullptr) {\n"
       "    auto* p = CreateMaybeMessage<$type$>(GetArenaForAllocation());\n");
   if (implicit_weak_field_) {
-    format("    $name$_ = reinterpret_cast<::$proto_ns$::MessageLite*>(p);\n");
+    format("    $field$ = reinterpret_cast<::$proto_ns$::MessageLite*>(p);\n");
   } else {
-    format("    $name$_ = p;\n");
+    format("    $field$ = p;\n");
   }
   format(
       "  }\n"
@@ -259,9 +258,9 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
   format("  if (message_arena == nullptr) {\n");
   if (IsCrossFileMessage(descriptor_)) {
     format(
-        "    delete reinterpret_cast< ::$proto_ns$::MessageLite*>($name$_);\n");
+        "    delete reinterpret_cast< ::$proto_ns$::MessageLite*>($field$);\n");
   } else {
-    format("    delete $name$_;\n");
+    format("    delete $field$;\n");
   }
   format(
       "  }\n"
@@ -271,14 +270,13 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
     // isn't defined in this file.
     format(
         "    ::$proto_ns$::Arena* submessage_arena =\n"
-        "        ::$proto_ns$::Arena::InternalHelper<\n"
-        "            ::$proto_ns$::MessageLite>::GetOwningArena(\n"
+        "        ::$proto_ns$::Arena::InternalGetOwningArena(\n"
         "                reinterpret_cast<::$proto_ns$::MessageLite*>("
         "$name$));\n");
   } else {
     format(
         "    ::$proto_ns$::Arena* submessage_arena =\n"
-        "        ::$proto_ns$::Arena::InternalHelper<$type$>::GetOwningArena("
+        "        ::$proto_ns$::Arena::InternalGetOwningArena("
         "$name$);\n");
   }
   format(
@@ -291,9 +289,9 @@ void MessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "    $clear_hasbit$\n"
       "  }\n");
   if (implicit_weak_field_) {
-    format("  $name$_ = reinterpret_cast<MessageLite*>($name$);\n");
+    format("  $field$ = reinterpret_cast<MessageLite*>($name$);\n");
   } else {
-    format("  $name$_ = $name$;\n");
+    format("  $field$ = $name$;\n");
   }
   format(
       "$annotate_set$"
@@ -328,8 +326,8 @@ void MessageFieldGenerator::GenerateInternalAccessorDefinitions(
     format(
         "const ::$proto_ns$::MessageLite& $classname$::_Internal::$name$(\n"
         "    const $classname$* msg) {\n"
-        "  if (msg->$field_member$ != nullptr) {\n"
-        "    return *msg->$field_member$;\n"
+        "  if (msg->$field$ != nullptr) {\n"
+        "    return *msg->$field$;\n"
         "  } else {\n"
         "    return *$type_default_instance_ptr$;\n"
         "  }\n"
@@ -341,7 +339,7 @@ void MessageFieldGenerator::GenerateInternalAccessorDefinitions(
       format("  msg->$set_hasbit$\n");
     }
     if (descriptor_->real_containing_oneof() == nullptr) {
-      format("  if (msg->$field_member$ == nullptr) {\n");
+      format("  if (msg->$field$ == nullptr) {\n");
     } else {
       format(
           "  if (!msg->_internal_has_$name$()) {\n"
@@ -349,10 +347,10 @@ void MessageFieldGenerator::GenerateInternalAccessorDefinitions(
           "    msg->set_has_$name$();\n");
     }
     format(
-        "    msg->$field_member$ = $type_default_instance_ptr$->New(\n"
+        "    msg->$field$ = $type_default_instance_ptr$->New(\n"
         "        msg->GetArenaForAllocation());\n"
         "  }\n"
-        "  return msg->$field_member$;\n"
+        "  return msg->$field$;\n"
         "}\n");
   } else {
     // This inline accessor directly returns member field and is used in
@@ -361,7 +359,7 @@ void MessageFieldGenerator::GenerateInternalAccessorDefinitions(
     format(
         "const $type$&\n"
         "$classname$::_Internal::$name$(const $classname$* msg) {\n"
-        "  return *msg->$field_member$;\n"
+        "  return *msg->$field$;\n"
         "}\n");
   }
 }
@@ -374,12 +372,12 @@ void MessageFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
     // If we don't have has-bits, message presence is indicated only by ptr !=
     // nullptr. Thus on clear, we need to delete the object.
     format(
-        "if (GetArenaForAllocation() == nullptr && $name$_ != nullptr) {\n"
-        "  delete $name$_;\n"
+        "if (GetArenaForAllocation() == nullptr && $field$ != nullptr) {\n"
+        "  delete $field$;\n"
         "}\n"
-        "$name$_ = nullptr;\n");
+        "$field$ = nullptr;\n");
   } else {
-    format("if ($name$_ != nullptr) $name$_->Clear();\n");
+    format("if ($field$ != nullptr) $field$->Clear();\n");
   }
 }
 
@@ -392,14 +390,14 @@ void MessageFieldGenerator::GenerateMessageClearingCode(
     // If we don't have has-bits, message presence is indicated only by ptr !=
     // nullptr. Thus on clear, we need to delete the object.
     format(
-        "if (GetArenaForAllocation() == nullptr && $name$_ != nullptr) {\n"
-        "  delete $name$_;\n"
+        "if (GetArenaForAllocation() == nullptr && $field$ != nullptr) {\n"
+        "  delete $field$;\n"
         "}\n"
-        "$name$_ = nullptr;\n");
+        "$field$ = nullptr;\n");
   } else {
     format(
-        "$DCHK$($name$_ != nullptr);\n"
-        "$name$_->Clear();\n");
+        "$DCHK$($field$ != nullptr);\n"
+        "$field$->Clear();\n");
   }
 }
 
@@ -422,7 +420,7 @@ void MessageFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
-  format("swap($name$_, other->$name$_);\n");
+  format("swap($field$, other->$field$);\n");
 }
 
 void MessageFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
@@ -487,7 +485,7 @@ void MessageFieldGenerator::GenerateByteSize(io::Printer* printer) const {
   format(
       "total_size += $tag_size$ +\n"
       "  ::$proto_ns$::internal::WireFormatLite::$declared_type$Size(\n"
-      "    *$field_member$);\n");
+      "    *$field$);\n");
 }
 
 void MessageFieldGenerator::GenerateIsInitialized(io::Printer* printer) const {
@@ -498,7 +496,7 @@ void MessageFieldGenerator::GenerateIsInitialized(io::Printer* printer) const {
   Formatter format(printer, variables_);
   format(
       "if (_internal_has_$name$()) {\n"
-      "  if (!$name$_->IsInitialized()) return false;\n"
+      "  if (!$field$->IsInitialized()) return false;\n"
       "}\n");
 }
 
@@ -532,15 +530,13 @@ void MessageOneofFieldGenerator::GenerateNonInlineAccessorDefinitions(
     // isn't defined in this file.
     format(
         "    ::$proto_ns$::Arena* submessage_arena =\n"
-        "        ::$proto_ns$::Arena::InternalHelper<\n"
-        "            ::$proto_ns$::MessageLite>::GetOwningArena(\n"
+        "        ::$proto_ns$::Arena::InternalGetOwningArena(\n"
         "                reinterpret_cast<::$proto_ns$::MessageLite*>("
         "$name$));\n");
   } else {
     format(
         "    ::$proto_ns$::Arena* submessage_arena =\n"
-        "      ::$proto_ns$::Arena::InternalHelper<"
-        "$type$>::GetOwningArena($name$);\n");
+        "      ::$proto_ns$::Arena::InternalGetOwningArena($name$);\n");
   }
   format(
       "    if (message_arena != submessage_arena) {\n"
@@ -548,7 +544,7 @@ void MessageOneofFieldGenerator::GenerateNonInlineAccessorDefinitions(
       "          message_arena, $name$, submessage_arena);\n"
       "    }\n"
       "    set_has_$name$();\n"
-      "    $field_member$ = $name$;\n"
+      "    $field$ = $name$;\n"
       "  }\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
@@ -569,7 +565,7 @@ void MessageOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "    if (GetArenaForAllocation() != nullptr) {\n"
       "      temp = ::$proto_ns$::internal::DuplicateIfNonNull(temp);\n"
       "    }\n"
-      "    $field_member$ = nullptr;\n"
+      "    $field$ = nullptr;\n"
       "    return temp;\n"
       "  } else {\n"
       "    return nullptr;\n"
@@ -596,7 +592,7 @@ void MessageOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "  if (_internal_has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    $type$* temp = $casted_member$;\n"
-      "    $field_member$ = nullptr;\n"
+      "    $field$ = nullptr;\n"
       "    return temp;\n"
       "  } else {\n"
       "    return nullptr;\n"
@@ -612,10 +608,10 @@ void MessageOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "    set_has_$name$();\n");
   if (implicit_weak_field_) {
     format(
-        "    $field_member$ = "
+        "    $field$ = "
         "reinterpret_cast<::$proto_ns$::MessageLite*>($name$);\n");
   } else {
-    format("    $field_member$ = $name$;\n");
+    format("    $field$ = $name$;\n");
   }
   format(
       "  }\n"
@@ -630,12 +626,12 @@ void MessageOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "    set_has_$name$();\n");
   if (implicit_weak_field_) {
     format(
-        "    $field_member$ = "
+        "    $field$ = "
         "reinterpret_cast<::$proto_ns$::MessageLite*>(CreateMaybeMessage< "
         "$type$ >(GetArenaForAllocation()));\n");
   } else {
     format(
-        "    $field_member$ = CreateMaybeMessage< $type$ "
+        "    $field$ = CreateMaybeMessage< $type$ "
         ">(GetArenaForAllocation());\n");
   }
   format(
@@ -657,7 +653,7 @@ void MessageOneofFieldGenerator::GenerateClearingCode(
   Formatter format(printer, variables_);
   format(
       "if (GetArenaForAllocation() == nullptr) {\n"
-      "  delete $field_member$;\n"
+      "  delete $field$;\n"
       "}\n");
 }
 
@@ -690,7 +686,7 @@ void MessageOneofFieldGenerator::GenerateIsInitialized(
   Formatter format(printer, variables_);
   format(
       "if (_internal_has_$name$()) {\n"
-      "  if (!$field_member$->IsInitialized()) return false;\n"
+      "  if (!$field$->IsInitialized()) return false;\n"
       "}\n");
 }
 
@@ -769,21 +765,21 @@ void RepeatedMessageFieldGenerator::GenerateInlineAccessorDefinitions(
       // TODO(dlj): move insertion points
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "$type_reference_function$"
-      "  return $name$_$weak$.Mutable(index);\n"
+      "  return $field$$weak$.Mutable(index);\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedPtrField< $type$ >*\n"
       "$classname$::mutable_$name$() {\n"
       "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
       "$type_reference_function$"
-      "  return &$name$_$weak$;\n"
+      "  return &$field$$weak$;\n"
       "}\n");
 
   if (options_.safe_boundary_check) {
     format(
         "inline const $type$& $classname$::_internal_$name$(int index) const "
         "{\n"
-        "  return $name$_$weak$.InternalCheckedGet(index,\n"
+        "  return $field$$weak$.InternalCheckedGet(index,\n"
         "      reinterpret_cast<const $type$&>($type_default_instance$));\n"
         "}\n");
   } else {
@@ -791,7 +787,7 @@ void RepeatedMessageFieldGenerator::GenerateInlineAccessorDefinitions(
         "inline const $type$& $classname$::_internal_$name$(int index) const "
         "{\n"
         "$type_reference_function$"
-        "  return $name$_$weak$.Get(index);\n"
+        "  return $field$$weak$.Get(index);\n"
         "}\n");
   }
 
@@ -802,7 +798,7 @@ void RepeatedMessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "  return _internal_$name$(index);\n"
       "}\n"
       "inline $type$* $classname$::_internal_add_$name$() {\n"
-      "  return $name$_$weak$.Add();\n"
+      "  return $field$$weak$.Add();\n"
       "}\n"
       "inline $type$* $classname$::add_$name$() {\n"
       "  $type$* _add = _internal_add_$name$();\n"
@@ -817,7 +813,7 @@ void RepeatedMessageFieldGenerator::GenerateInlineAccessorDefinitions(
       "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
       "$type_reference_function$"
-      "  return $name$_$weak$;\n"
+      "  return $field$$weak$;\n"
       "}\n");
 }
 
@@ -826,7 +822,7 @@ void RepeatedMessageFieldGenerator::GenerateClearingCode(
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
-  format("$name$_.Clear();\n");
+  format("$field$.Clear();\n");
 }
 
 void RepeatedMessageFieldGenerator::GenerateMergingCode(
@@ -834,7 +830,7 @@ void RepeatedMessageFieldGenerator::GenerateMergingCode(
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
-  format("$name$_.MergeFrom(from.$name$_);\n");
+  format("$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedMessageFieldGenerator::GenerateSwappingCode(
@@ -842,7 +838,7 @@ void RepeatedMessageFieldGenerator::GenerateSwappingCode(
   GOOGLE_CHECK(!IsFieldStripped(descriptor_, options_));
 
   Formatter format(printer, variables_);
-  format("$name$_.InternalSwap(&other->$name$_);\n");
+  format("$field$.InternalSwap(&other->$field$);\n");
 }
 
 void RepeatedMessageFieldGenerator::GenerateConstructorCode(
@@ -857,8 +853,8 @@ void RepeatedMessageFieldGenerator::GenerateSerializeWithCachedSizesToArray(
   Formatter format(printer, variables_);
   if (implicit_weak_field_) {
     format(
-        "for (auto it = this->$name$_.pointer_begin(),\n"
-        "          end = this->$name$_.pointer_end(); it < end; ++it) {\n");
+        "for (auto it = this->$field$.pointer_begin(),\n"
+        "          end = this->$field$.pointer_end(); it < end; ++it) {\n");
     if (descriptor_->type() == FieldDescriptor::TYPE_MESSAGE) {
       format(
           "  target = ::$proto_ns$::internal::WireFormatLite::\n"
@@ -902,7 +898,7 @@ void RepeatedMessageFieldGenerator::GenerateByteSize(
   Formatter format(printer, variables_);
   format(
       "total_size += $tag_size$UL * this->_internal_$name$_size();\n"
-      "for (const auto& msg : this->$name$_) {\n"
+      "for (const auto& msg : this->$field$) {\n"
       "  total_size +=\n"
       "    ::$proto_ns$::internal::WireFormatLite::$declared_type$Size(msg);\n"
       "}\n");
@@ -917,11 +913,11 @@ void RepeatedMessageFieldGenerator::GenerateIsInitialized(
   Formatter format(printer, variables_);
   if (implicit_weak_field_) {
     format(
-        "if (!::$proto_ns$::internal::AllAreInitializedWeak($name$_.weak))\n"
+        "if (!::$proto_ns$::internal::AllAreInitializedWeak($field$.weak))\n"
         "  return false;\n");
   } else {
     format(
-        "if (!::$proto_ns$::internal::AllAreInitialized($name$_))\n"
+        "if (!::$proto_ns$::internal::AllAreInitialized($field$))\n"
         "  return false;\n");
   }
 }

src/google/protobuf/compiler/cpp/cpp_parse_function_generator.cc

@@ -88,8 +88,7 @@ bool IsFieldEligibleForFastParsing(
     return false;
   }
   switch (field->type()) {
-    // Strings, enums, and groups are not handled on the fast path.
-    case FieldDescriptor::TYPE_STRING:
+    // Groups are not handled on the fast path.
     case FieldDescriptor::TYPE_GROUP:
       return false;
 
@@ -105,6 +104,7 @@ bool IsFieldEligibleForFastParsing(
       break;
 
       // Some bytes fields can be handled on fast path.
+    case FieldDescriptor::TYPE_STRING:
     case FieldDescriptor::TYPE_BYTES:
       if (field->options().ctype() != FieldOptions::STRING ||
           !field->default_value_string().empty() ||
@@ -233,8 +233,8 @@ std::vector<const FieldDescriptor*> FilterMiniParsedFields(
         }
         break;
 
-        // TODO(b/209516305): add TYPE_STRING once field names are available.
         case FieldDescriptor::TYPE_BYTES:
+        case FieldDescriptor::TYPE_STRING:
           if (IsStringInlined(field, options)) {
             // TODO(b/198211897): support InilnedStringField.
             handled = false;
@@ -773,9 +773,9 @@ void ParseFunctionGenerator::GenerateFastFieldEntries(Formatter& format) {
     } else {
       format(
           "{$1$,\n"
-          " {$2$, $3$, $4$, PROTOBUF_FIELD_OFFSET($classname$, $5$_)}},\n",
+          " {$2$, $3$, $4$, PROTOBUF_FIELD_OFFSET($classname$, $5$)}},\n",
           info.func_name, info.coded_tag, info.hasbit_idx, info.aux_idx,
-          FieldName(info.field));
+          FieldMemberName(info.field));
     }
   }
 }
@@ -999,7 +999,7 @@ void ParseFunctionGenerator::GenerateArenaString(Formatter& format,
                 "::" + MakeDefaultName(field) + ".get()";
   format(
       "if (arena != nullptr) {\n"
-      "  ptr = ctx->ReadArenaString(ptr, &$msg$$name$_, arena");
+      "  ptr = ctx->ReadArenaString(ptr, &$msg$$field$, arena");
   if (IsStringInlined(field, options_)) {
     GOOGLE_DCHECK(!inlined_string_indices_.empty());
     int inlined_string_index = inlined_string_indices_[field->index()];
@@ -1018,10 +1018,9 @@ void ParseFunctionGenerator::GenerateArenaString(Formatter& format,
       ");\n"
       "} else {\n"
       "  ptr = ::_pbi::InlineGreedyStringParser("
-      "$msg$$name$_.MutableNoArenaNoDefault(&$1$), ptr, ctx);\n"
+      "$msg$$field$.MutableNoCopy(nullptr), ptr, ctx);\n"
       "}\n"
-      "const std::string* str = &$msg$$name$_.Get(); (void)str;\n",
-      default_string);
+      "const std::string* str = &$msg$$field$.Get(); (void)str;\n");
 }
 
 void ParseFunctionGenerator::GenerateStrings(Formatter& format,
@@ -1130,13 +1129,13 @@ void ParseFunctionGenerator::GenerateLengthDelim(Formatter& format,
             format(
                 "auto object = "
                 "::$proto_ns$::internal::InitEnumParseWrapper<"
-                "$unknown_fields_type$>(&$msg$$name$_, $1$_IsValid, "
+                "$unknown_fields_type$>(&$msg$$field$, $1$_IsValid, "
                 "$2$, &$msg$_internal_metadata_);\n"
                 "ptr = ctx->ParseMessage(&object, ptr);\n",
                 QualifiedClassName(val->enum_type(), options_),
                 field->number());
           } else {
-            format("ptr = ctx->ParseMessage(&$msg$$name$_, ptr);\n");
+            format("ptr = ctx->ParseMessage(&$msg$$field$, ptr);\n");
           }
         } else if (IsLazy(field, options_, scc_analyzer_)) {
           bool eager_verify =
@@ -1153,19 +1152,19 @@ void ParseFunctionGenerator::GenerateLengthDelim(Formatter& format,
             format(
                 "if (!$msg$_internal_has_$name$()) {\n"
                 "  $msg$clear_$1$();\n"
-                "  $msg$$1$_.$name$_ = ::$proto_ns$::Arena::CreateMessage<\n"
+                "  $msg$$field$ = ::$proto_ns$::Arena::CreateMessage<\n"
                 "      ::$proto_ns$::internal::LazyField>("
                 "$msg$GetArenaForAllocation());\n"
                 "  $msg$set_has_$name$();\n"
                 "}\n"
-                "auto* lazy_field = $msg$$1$_.$name$_;\n",
+                "auto* lazy_field = $msg$$field$;\n",
                 field->containing_oneof()->name());
           } else if (HasHasbit(field)) {
             format(
                 "_Internal::set_has_$name$(&$has_bits$);\n"
-                "auto* lazy_field = &$msg$$name$_;\n");
+                "auto* lazy_field = &$msg$$field$;\n");
           } else {
-            format("auto* lazy_field = &$msg$$name$_;\n");
+            format("auto* lazy_field = &$msg$$field$;\n");
           }
           format(
               "::$proto_ns$::internal::LazyFieldParseHelper<\n"
@@ -1188,7 +1187,7 @@ void ParseFunctionGenerator::GenerateLengthDelim(Formatter& format,
                 "ptr);\n");
           } else {
             format(
-                "ptr = ctx->ParseMessage($msg$$name$_.AddWeak("
+                "ptr = ctx->ParseMessage($msg$$field$.AddWeak("
                 "reinterpret_cast<const ::$proto_ns$::MessageLite*>($1$ptr_)"
                 "), ptr);\n",
                 QualifiedDefaultInstanceName(field->message_type(), options_));
@@ -1287,7 +1286,7 @@ void ParseFunctionGenerator::GenerateFieldBody(
             format("_Internal::set_has_$name$(&$has_bits$);\n");
           }
           format(
-              "$msg$$name$_ = ::$proto_ns$::internal::ReadVarint$1$$2$(&ptr);\n"
+              "$msg$$field$ = ::$proto_ns$::internal::ReadVarint$1$$2$(&ptr);\n"
               "CHK_(ptr);\n",
               zigzag, size);
         }
@@ -1434,6 +1433,8 @@ void ParseFunctionGenerator::GenerateFieldSwitch(
   format.Indent();
 
   for (const auto* field : fields) {
+    // Set abbreviated form instead of field_member.
+    format.Set("field", FieldMemberName(field));
     PrintFieldComment(format, field);
     format("case $1$:\n", field->number());
     format.Indent();

src/google/protobuf/compiler/cpp/cpp_primitive_field.cc

@@ -150,7 +150,7 @@ void PrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
   Formatter format(printer, variables_);
   format(
       "inline $type$ $classname$::_internal_$name$() const {\n"
-      "  return $name$_;\n"
+      "  return $field$;\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
       "$annotate_get$"
@@ -159,7 +159,7 @@ void PrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline void $classname$::_internal_set_$name$($type$ value) {\n"
       "  $set_hasbit$\n"
-      "  $name$_ = value;\n"
+      "  $field$ = value;\n"
       "}\n"
       "inline void $classname$::set_$name$($type$ value) {\n"
       "  _internal_set_$name$(value);\n"
@@ -170,7 +170,7 @@ void PrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
 
 void PrimitiveFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_ = $default$;\n");
+  format("$field$ = $default$;\n");
 }
 
 void PrimitiveFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
@@ -180,7 +180,7 @@ void PrimitiveFieldGenerator::GenerateMergingCode(io::Printer* printer) const {
 
 void PrimitiveFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("swap($name$_, other->$name$_);\n");
+  format("swap($field$, other->$field$);\n");
 }
 
 void PrimitiveFieldGenerator::GenerateConstructorCode(
@@ -249,7 +249,7 @@ void PrimitiveOneofFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline $type$ $classname$::_internal_$name$() const {\n"
       "  if (_internal_has_$name$()) {\n"
-      "    return $field_member$;\n"
+      "    return $field$;\n"
       "  }\n"
       "  return $default$;\n"
       "}\n"
@@ -258,7 +258,7 @@ void PrimitiveOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
       "  }\n"
-      "  $field_member$ = value;\n"
+      "  $field$ = value;\n"
       "}\n"
       "inline $type$ $classname$::$name$() const {\n"
       "$annotate_get$"
@@ -275,7 +275,7 @@ void PrimitiveOneofFieldGenerator::GenerateInlineAccessorDefinitions(
 void PrimitiveOneofFieldGenerator::GenerateClearingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$field_member$ = $default$;\n");
+  format("$field$ = $default$;\n");
 }
 
 void PrimitiveOneofFieldGenerator::GenerateSwappingCode(
@@ -344,7 +344,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
   Formatter format(printer, variables_);
   format(
       "inline $type$ $classname$::_internal_$name$(int index) const {\n"
-      "  return $name$_.Get(index);\n"
+      "  return $field$.Get(index);\n"
       "}\n"
       "inline $type$ $classname$::$name$(int index) const {\n"
       "$annotate_get$"
@@ -353,11 +353,11 @@ void RepeatedPrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline void $classname$::set_$name$(int index, $type$ value) {\n"
       "$annotate_set$"
-      "  $name$_.Set(index, value);\n"
+      "  $field$.Set(index, value);\n"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::_internal_add_$name$($type$ value) {\n"
-      "  $name$_.Add(value);\n"
+      "  $field$.Add(value);\n"
       "}\n"
       "inline void $classname$::add_$name$($type$ value) {\n"
       "  _internal_add_$name$(value);\n"
@@ -366,7 +366,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline const ::$proto_ns$::RepeatedField< $type$ >&\n"
       "$classname$::_internal_$name$() const {\n"
-      "  return $name$_;\n"
+      "  return $field$;\n"
       "}\n"
       "inline const ::$proto_ns$::RepeatedField< $type$ >&\n"
       "$classname$::$name$() const {\n"
@@ -376,7 +376,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline ::$proto_ns$::RepeatedField< $type$ >*\n"
       "$classname$::_internal_mutable_$name$() {\n"
-      "  return &$name$_;\n"
+      "  return &$field$;\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedField< $type$ >*\n"
       "$classname$::mutable_$name$() {\n"
@@ -389,30 +389,19 @@ void RepeatedPrimitiveFieldGenerator::GenerateInlineAccessorDefinitions(
 void RepeatedPrimitiveFieldGenerator::GenerateClearingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.Clear();\n");
+  format("$field$.Clear();\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.MergeFrom(from.$name$_);\n");
+  format("$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::GenerateSwappingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.InternalSwap(&other->$name$_);\n");
-}
-
-void RepeatedPrimitiveFieldGenerator::GenerateConstructorCode(
-    io::Printer* printer) const {
-  // Not needed for repeated fields.
-}
-
-void RepeatedPrimitiveFieldGenerator::GenerateCopyConstructorCode(
-    io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$name$_.CopyFrom(from.$name$_);\n");
+  format("$field$.InternalSwap(&other->$field$);\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::GenerateSerializeWithCachedSizesToArray(
@@ -456,7 +445,7 @@ void RepeatedPrimitiveFieldGenerator::GenerateByteSize(
   if (fixed_size == -1) {
     format(
         "size_t data_size = ::_pbi::WireFormatLite::\n"
-        "  $declared_type$Size(this->$name$_);\n");
+        "  $declared_type$Size(this->$field$);\n");
   } else {
     format(
         "unsigned int count = static_cast<unsigned "

src/google/protobuf/compiler/cpp/cpp_primitive_field.h

@@ -98,8 +98,8 @@ class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
   void GenerateClearingCode(io::Printer* printer) const override;
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
-  void GenerateConstructorCode(io::Printer* printer) const override;
-  void GenerateCopyConstructorCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;

src/google/protobuf/compiler/cpp/cpp_string_field.cc

@@ -54,8 +54,6 @@ void SetStringVariables(const FieldDescriptor* descriptor,
 
   const std::string kNS = "::" + (*variables)["proto_ns"] + "::internal::";
   const std::string kArenaStringPtr = kNS + "ArenaStringPtr";
-  const std::string kEmptyDefault = kArenaStringPtr + "::EmptyDefault{}";
-  const std::string kNonEmptyDefault = kArenaStringPtr + "::NonEmptyDefault{}";
 
   (*variables)["default"] = DefaultValue(options, descriptor);
   (*variables)["default_length"] =
@@ -64,21 +62,17 @@ void SetStringVariables(const FieldDescriptor* descriptor,
   (*variables)["default_variable_name"] = default_variable_string;
 
   if (descriptor->default_value_string().empty()) {
-    (*variables)["init_value"] = "";
     (*variables)["default_string"] = kNS + "GetEmptyStringAlreadyInited()";
     (*variables)["default_value"] = "&" + (*variables)["default_string"];
-    (*variables)["default_value_tag"] = kEmptyDefault;
-    (*variables)["default_variable_or_tag"] = kEmptyDefault;
+    (*variables)["lazy_variable_args"] = "";
   } else {
     (*variables)["lazy_variable"] =
         QualifiedClassName(descriptor->containing_type(), options) +
         "::" + default_variable_string;
 
-    (*variables)["init_value"] = "nullptr";
     (*variables)["default_string"] = (*variables)["lazy_variable"] + ".get()";
     (*variables)["default_value"] = "nullptr";
-    (*variables)["default_value_tag"] = kNonEmptyDefault;
-    (*variables)["default_variable_or_tag"] = (*variables)["lazy_variable"];
+    (*variables)["lazy_variable_args"] = (*variables)["lazy_variable"] + ", ";
   }
 
   (*variables)["pointer_type"] =
@@ -210,7 +204,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
       "  // @@protoc_insertion_point(field_get:$full_name$)\n");
   if (!descriptor_->default_value_string().empty()) {
     format(
-        "  if ($name$_.IsDefault()) return "
+        "  if ($field$.IsDefault()) return "
         "$default_variable_name$.get();\n");
   }
   format(
@@ -222,7 +216,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
         "inline PROTOBUF_ALWAYS_INLINE\n"
         "void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
         " $set_hasbit$\n"
-        " $name$_.$setter$($default_value_tag$, static_cast<ArgT0 &&>(arg0),"
+        " $field$.$setter$(static_cast<ArgT0 &&>(arg0),"
         " args..., GetArenaForAllocation());\n"
         "$annotate_set$"
         "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -233,7 +227,7 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
         "inline PROTOBUF_ALWAYS_INLINE\n"
         "void $classname$::set_$name$(ArgT0&& arg0, ArgT... args) {\n"
         " $set_hasbit$\n"
-        " $name$_.$setter$(nullptr, static_cast<ArgT0 &&>(arg0),"
+        " $field$.$setter$(static_cast<ArgT0 &&>(arg0),"
         " args..., GetArenaForAllocation(), _internal_$name$_donated(), "
         "&$donating_states_word$, $mask_for_undonate$, this);\n"
         "$annotate_set$"
@@ -252,18 +246,18 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
       "  return _s;\n"
       "}\n"
       "inline const std::string& $classname$::_internal_$name$() const {\n"
-      "  return $name$_.Get();\n"
+      "  return $field$.Get();\n"
       "}\n"
       "inline void $classname$::_internal_set_$name$(const std::string& "
       "value) {\n"
       "  $set_hasbit$\n");
   if (!inlined_) {
     format(
-        "  $name$_.Set($default_value_tag$, value, GetArenaForAllocation());\n"
+        "  $field$.Set(value, GetArenaForAllocation());\n"
         "}\n");
   } else {
     format(
-        "  $name$_.Set(nullptr, value, GetArenaForAllocation(),\n"
+        "  $field$.Set(value, GetArenaForAllocation(),\n"
         "    _internal_$name$_donated(), &$donating_states_word$, "
         "$mask_for_undonate$, this);\n"
         "}\n");
@@ -273,12 +267,12 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
       "  $set_hasbit$\n");
   if (!inlined_) {
     format(
-        "  return $name$_.Mutable($default_variable_or_tag$, "
+        "  return $field$.Mutable($lazy_variable_args$"
         "GetArenaForAllocation());\n"
         "}\n");
   } else {
     format(
-        "  return $name$_.Mutable($default_variable_or_tag$, "
+        "  return $field$.Mutable($lazy_variable_args$"
         "GetArenaForAllocation(), _internal_$name$_donated(), "
         "&$donating_states_word$, $mask_for_undonate$, this);\n"
         "}\n");
@@ -295,26 +289,23 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
         "  }\n"
         "  $clear_hasbit$\n");
     if (!inlined_) {
-      format(
-          "  auto* p = $name$_.ReleaseNonDefault($default_value$, "
-          "GetArenaForAllocation());\n");
+      format("  auto* p = $field$.Release();\n");
       if (descriptor_->default_value_string().empty()) {
         format(
             "#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING\n"
-            "  if ($name$_.IsDefault()) {\n"
-            "    $name$_.Set($default_value$, \"\", GetArenaForAllocation());\n"
+            "  if ($field$.IsDefault()) {\n"
+            "    $field$.Set(\"\", GetArenaForAllocation());\n"
             "  }\n"
             "#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING\n");
       }
       format("  return p;\n");
     } else {
       format(
-          "  return $name$_.Release(nullptr, GetArenaForAllocation(), "
+          "  return $field$.Release(GetArenaForAllocation(), "
           "_internal_$name$_donated());\n");
     }
   } else {
-    format(
-        "  return $name$_.Release($default_value$, GetArenaForAllocation());\n");
+    format("  return $field$.Release();\n");
   }
 
   format(
@@ -326,21 +317,19 @@ void StringFieldGenerator::GenerateInlineAccessorDefinitions(
       "    $clear_hasbit$\n"
       "  }\n");
   if (!inlined_) {
-    format(
-        "  $name$_.SetAllocated($default_value$, $name$,\n"
-        "      GetArenaForAllocation());\n");
+    format("  $field$.SetAllocated($name$, GetArenaForAllocation());\n");
     if (descriptor_->default_value_string().empty()) {
       format(
           "#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING\n"
-          "  if ($name$_.IsDefault()) {\n"
-          "    $name$_.Set($default_value$, \"\", GetArenaForAllocation());\n"
+          "  if ($field$.IsDefault()) {\n"
+          "    $field$.Set(\"\", GetArenaForAllocation());\n"
           "  }\n"
           "#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING\n");
     }
   } else {
     // Currently, string fields with default value can't be inlined.
     format(
-        "    $name$_.SetAllocated(nullptr, $name$, GetArenaForAllocation(), "
+        "    $field$.SetAllocated(nullptr, $name$, GetArenaForAllocation(), "
         "_internal_$name$_donated(), &$donating_states_word$, "
         "$mask_for_undonate$, this);\n");
   }
@@ -364,11 +353,11 @@ void StringFieldGenerator::GenerateNonInlineAccessorDefinitions(
 void StringFieldGenerator::GenerateClearingCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (descriptor_->default_value_string().empty()) {
-    format("$name$_.ClearToEmpty();\n");
+    format("$field$.ClearToEmpty();\n");
   } else {
     GOOGLE_DCHECK(!inlined_);
     format(
-        "$name$_.ClearToDefault($lazy_variable$, GetArenaForAllocation());\n");
+        "$field$.ClearToDefault($lazy_variable$, GetArenaForAllocation());\n");
   }
 }
 
@@ -394,20 +383,20 @@ void StringFieldGenerator::GenerateMessageClearingCode(
     //
     // For non-inlined strings, we distinguish from non-default by comparing
     // instances, rather than contents.
-    format("$DCHK$(!$name$_.IsDefault());\n");
+    format("$DCHK$(!$field$.IsDefault());\n");
   }
 
   if (descriptor_->default_value_string().empty()) {
     if (must_be_present) {
-      format("$name$_.ClearNonDefaultToEmpty();\n");
+      format("$field$.ClearNonDefaultToEmpty();\n");
     } else {
-      format("$name$_.ClearToEmpty();\n");
+      format("$field$.ClearToEmpty();\n");
     }
   } else {
     // Clear to a non-empty default is more involved, as we try to use the
     // Arena if one is present and may need to reallocate the string.
     format(
-        "$name$_.ClearToDefault($lazy_variable$, GetArenaForAllocation());\n ");
+        "$field$.ClearToDefault($lazy_variable$, GetArenaForAllocation());\n ");
   }
 }
 
@@ -422,16 +411,15 @@ void StringFieldGenerator::GenerateSwappingCode(io::Printer* printer) const {
   if (!inlined_) {
     format(
         "::$proto_ns$::internal::ArenaStringPtr::InternalSwap(\n"
-        "    $default_value$,\n"
-        "    &$name$_, lhs_arena,\n"
-        "    &other->$name$_, rhs_arena\n"
+        "    &$field$, lhs_arena,\n"
+        "    &other->$field$, rhs_arena\n"
         ");\n");
   } else {
     format(
         "::$proto_ns$::internal::InlinedStringField::InternalSwap(\n"
-        "  &$name$_, lhs_arena, "
+        "  &$field$, lhs_arena, "
         "(_inlined_string_donated_[0] & 0x1u) == 0, this,\n"
-        "  &other->$name$_, rhs_arena, "
+        "  &other->$field$, rhs_arena, "
         "(other->_inlined_string_donated_[0] & 0x1u) == 0, other);\n");
   }
 }
@@ -442,12 +430,12 @@ void StringFieldGenerator::GenerateConstructorCode(io::Printer* printer) const {
     return;
   }
   GOOGLE_DCHECK(!inlined_);
-  format("$name$_.InitDefault($init_value$);\n");
+  format("$name$_.InitDefault();\n");
   if (IsString(descriptor_, options_) &&
       descriptor_->default_value_string().empty()) {
     format(
         "#ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING\n"
-        "  $name$_.Set($default_value$, \"\", GetArenaForAllocation());\n"
+        "  $name$_.Set(\"\", GetArenaForAllocation());\n"
         "#endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING\n");
   }
 }
@@ -470,11 +458,11 @@ void StringFieldGenerator::GenerateCopyConstructorCode(
 
   if (!inlined_) {
     format(
-        "$name$_.Set($default_value_tag$, from._internal_$name$(), \n"
+        "$field$.Set(from._internal_$name$(), \n"
         "  GetArenaForAllocation());\n");
   } else {
     format(
-        "$name$_.Set(nullptr, from._internal_$name$(),\n"
+        "$field$.Set(from._internal_$name$(),\n"
         "  GetArenaForAllocation(), _internal_$name$_donated(), "
         "&$donating_states_word$, $mask_for_undonate$, this);\n");
   }
@@ -486,14 +474,14 @@ void StringFieldGenerator::GenerateCopyConstructorCode(
 void StringFieldGenerator::GenerateDestructorCode(io::Printer* printer) const {
   Formatter format(printer, variables_);
   if (!inlined_) {
-    format("$name$_.DestroyNoArena($default_value$);\n");
+    format("$field$.Destroy();\n");
     return;
   }
   // Explicitly calls ~InlinedStringField as its automatic call is disabled.
   // Destructor has been implicitly skipped as a union, and even the
   // message-owned arena is enabled, arena could still be missing for
   // Arena::CreateMessage(nullptr).
-  format("$name$_.~InlinedStringField();\n");
+  format("$field$.~InlinedStringField();\n");
 }
 
 ArenaDtorNeeds StringFieldGenerator::NeedsArenaDestructor() const {
@@ -507,7 +495,7 @@ void StringFieldGenerator::GenerateArenaDestructorCode(
   // _this is the object being destructed (we are inside a static method here).
   format(
       "if (!_this->_internal_$name$_donated()) {\n"
-      "  _this->$name$_.~InlinedStringField();\n"
+      "  _this->$field$.~InlinedStringField();\n"
       "}\n");
 }
 
@@ -575,9 +563,9 @@ void StringOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "  if (!_internal_has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
-      "    $field_member$.InitDefault($init_value$);\n"
+      "    $field$.InitDefault();\n"
       "  }\n"
-      "  $field_member$.$setter$($default_value_tag$,"
+      "  $field$.$setter$("
       " static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
@@ -590,7 +578,7 @@ void StringOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "}\n"
       "inline const std::string& $classname$::_internal_$name$() const {\n"
       "  if (_internal_has_$name$()) {\n"
-      "    return $field_member$.Get();\n"
+      "    return $field$.Get();\n"
       "  }\n"
       "  return $default_string$;\n"
       "}\n"
@@ -599,28 +587,26 @@ void StringOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "  if (!_internal_has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
-      "    $field_member$.InitDefault($init_value$);\n"
+      "    $field$.InitDefault();\n"
       "  }\n"
-      "  $field_member$.Set($default_value_tag$, value, "
-      "GetArenaForAllocation());\n"
+      "  $field$.Set(value, GetArenaForAllocation());\n"
       "}\n");
   format(
       "inline std::string* $classname$::_internal_mutable_$name$() {\n"
       "  if (!_internal_has_$name$()) {\n"
       "    clear_$oneof_name$();\n"
       "    set_has_$name$();\n"
-      "    $field_member$.InitDefault($init_value$);\n"
+      "    $field$.InitDefault();\n"
       "  }\n"
-      "  return $field_member$.Mutable(\n"
-      "      $default_variable_or_tag$, GetArenaForAllocation());\n"
+      "  return $field$.Mutable($lazy_variable_args$"
+      "      GetArenaForAllocation());\n"
       "}\n"
       "inline std::string* $classname$::$release_name$() {\n"
       "$annotate_release$"
       "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if (_internal_has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
-      "    return $field_member$.ReleaseNonDefault($default_value$, "
-      "GetArenaForAllocation());\n"
+      "    return $field$.Release();\n"
       "  } else {\n"
       "    return nullptr;\n"
       "  }\n"
@@ -631,7 +617,7 @@ void StringOneofFieldGenerator::GenerateInlineAccessorDefinitions(
       "  }\n"
       "  if ($name$ != nullptr) {\n"
       "    set_has_$name$();\n"
-      "    $field_member$.InitAllocated($name$, GetArenaForAllocation());\n"
+      "    $field$.InitAllocated($name$, GetArenaForAllocation());\n"
       "  }\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
@@ -641,9 +627,7 @@ void StringOneofFieldGenerator::GenerateInlineAccessorDefinitions(
 void StringOneofFieldGenerator::GenerateClearingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format(
-      "$field_member$.Destroy($default_value_tag$, "
-      "GetArenaForAllocation());\n");
+  format("$field$.Destroy();\n");
 }
 
 void StringOneofFieldGenerator::GenerateMessageClearingCode(
@@ -758,14 +742,14 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
     format(
         "inline const std::string& $classname$::_internal_$name$(int index) "
         "const {\n"
-        "  return $name$_.InternalCheckedGet(\n"
+        "  return $field$.InternalCheckedGet(\n"
         "      index, ::$proto_ns$::internal::GetEmptyStringAlreadyInited());\n"
         "}\n");
   } else {
     format(
         "inline const std::string& $classname$::_internal_$name$(int index) "
         "const {\n"
-        "  return $name$_.Get(index);\n"
+        "  return $field$.Get(index);\n"
         "}\n");
   }
   format(
@@ -777,23 +761,23 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
       "inline std::string* $classname$::mutable_$name$(int index) {\n"
       "$annotate_mutable$"
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
-      "  return $name$_.Mutable(index);\n"
+      "  return $field$.Mutable(index);\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, const std::string& "
       "value) "
       "{\n"
-      "  $name$_.Mutable(index)->assign(value);\n"
+      "  $field$.Mutable(index)->assign(value);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, std::string&& value) {\n"
-      "  $name$_.Mutable(index)->assign(std::move(value));\n"
+      "  $field$.Mutable(index)->assign(std::move(value));\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set:$full_name$)\n"
       "}\n"
       "inline void $classname$::set_$name$(int index, const char* value) {\n"
       "  $null_check$"
-      "  $name$_.Mutable(index)->assign(value);\n"
+      "  $field$.Mutable(index)->assign(value);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_char:$full_name$)\n"
       "}\n");
@@ -801,7 +785,7 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
     format(
         "inline void "
         "$classname$::set_$name$(int index, StringPiece value) {\n"
-        "  $name$_.Mutable(index)->assign(value.data(), value.size());\n"
+        "  $field$.Mutable(index)->assign(value.data(), value.size());\n"
         "$annotate_set$"
         "  // @@protoc_insertion_point(field_set_string_piece:$full_name$)\n"
         "}\n");
@@ -810,34 +794,34 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
       "inline void "
       "$classname$::set_$name$"
       "(int index, const $pointer_type$* value, size_t size) {\n"
-      "  $name$_.Mutable(index)->assign(\n"
+      "  $field$.Mutable(index)->assign(\n"
       "    reinterpret_cast<const char*>(value), size);\n"
       "$annotate_set$"
       "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
       "}\n"
       "inline std::string* $classname$::_internal_add_$name$() {\n"
-      "  return $name$_.Add();\n"
+      "  return $field$.Add();\n"
       "}\n"
       "inline void $classname$::add_$name$(const std::string& value) {\n"
-      "  $name$_.Add()->assign(value);\n"
+      "  $field$.Add()->assign(value);\n"
       "$annotate_add$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline void $classname$::add_$name$(std::string&& value) {\n"
-      "  $name$_.Add(std::move(value));\n"
+      "  $field$.Add(std::move(value));\n"
       "$annotate_add$"
       "  // @@protoc_insertion_point(field_add:$full_name$)\n"
       "}\n"
       "inline void $classname$::add_$name$(const char* value) {\n"
       "  $null_check$"
-      "  $name$_.Add()->assign(value);\n"
+      "  $field$.Add()->assign(value);\n"
       "$annotate_add$"
       "  // @@protoc_insertion_point(field_add_char:$full_name$)\n"
       "}\n");
   if (!options_.opensource_runtime) {
     format(
         "inline void $classname$::add_$name$(StringPiece value) {\n"
-        "  $name$_.Add()->assign(value.data(), value.size());\n"
+        "  $field$.Add()->assign(value.data(), value.size());\n"
         "$annotate_add$"
         "  // @@protoc_insertion_point(field_add_string_piece:$full_name$)\n"
         "}\n");
@@ -845,7 +829,7 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
   format(
       "inline void "
       "$classname$::add_$name$(const $pointer_type$* value, size_t size) {\n"
-      "  $name$_.Add()->assign(reinterpret_cast<const char*>(value), size);\n"
+      "  $field$.Add()->assign(reinterpret_cast<const char*>(value), size);\n"
       "$annotate_add$"
       "  // @@protoc_insertion_point(field_add_pointer:$full_name$)\n"
       "}\n"
@@ -853,43 +837,32 @@ void RepeatedStringFieldGenerator::GenerateInlineAccessorDefinitions(
       "$classname$::$name$() const {\n"
       "$annotate_list$"
       "  // @@protoc_insertion_point(field_list:$full_name$)\n"
-      "  return $name$_;\n"
+      "  return $field$;\n"
       "}\n"
       "inline ::$proto_ns$::RepeatedPtrField<std::string>*\n"
       "$classname$::mutable_$name$() {\n"
       "$annotate_mutable_list$"
       "  // @@protoc_insertion_point(field_mutable_list:$full_name$)\n"
-      "  return &$name$_;\n"
+      "  return &$field$;\n"
       "}\n");
 }
 
 void RepeatedStringFieldGenerator::GenerateClearingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.Clear();\n");
+  format("$field$.Clear();\n");
 }
 
 void RepeatedStringFieldGenerator::GenerateMergingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.MergeFrom(from.$name$_);\n");
+  format("$field$.MergeFrom(from.$field$);\n");
 }
 
 void RepeatedStringFieldGenerator::GenerateSwappingCode(
     io::Printer* printer) const {
   Formatter format(printer, variables_);
-  format("$name$_.InternalSwap(&other->$name$_);\n");
-}
-
-void RepeatedStringFieldGenerator::GenerateConstructorCode(
-    io::Printer* printer) const {
-  // Not needed for repeated fields.
-}
-
-void RepeatedStringFieldGenerator::GenerateCopyConstructorCode(
-    io::Printer* printer) const {
-  Formatter format(printer, variables_);
-  format("$name$_.CopyFrom(from.$name$_);");
+  format("$field$.InternalSwap(&other->$field$);\n");
 }
 
 void RepeatedStringFieldGenerator::GenerateSerializeWithCachedSizesToArray(
@@ -916,11 +889,11 @@ void RepeatedStringFieldGenerator::GenerateByteSize(
   Formatter format(printer, variables_);
   format(
       "total_size += $tag_size$ *\n"
-      "    ::$proto_ns$::internal::FromIntSize($name$_.size());\n"
-      "for (int i = 0, n = $name$_.size(); i < n; i++) {\n"
+      "    ::$proto_ns$::internal::FromIntSize($field$.size());\n"
+      "for (int i = 0, n = $field$.size(); i < n; i++) {\n"
       "  total_size += "
       "::$proto_ns$::internal::WireFormatLite::$declared_type$Size(\n"
-      "    $name$_.Get(i));\n"
+      "    $field$.Get(i));\n"
       "}\n");
 }
 

src/google/protobuf/compiler/cpp/cpp_string_field.h

@@ -111,8 +111,8 @@ class RepeatedStringFieldGenerator : public FieldGenerator {
   void GenerateClearingCode(io::Printer* printer) const override;
   void GenerateMergingCode(io::Printer* printer) const override;
   void GenerateSwappingCode(io::Printer* printer) const override;
-  void GenerateConstructorCode(io::Printer* printer) const override;
-  void GenerateCopyConstructorCode(io::Printer* printer) const override;
+  void GenerateConstructorCode(io::Printer* printer) const override {}
+  void GenerateCopyConstructorCode(io::Printer* printer) const override {}
   void GenerateSerializeWithCachedSizesToArray(
       io::Printer* printer) const override;
   void GenerateByteSize(io::Printer* printer) const override;

src/google/protobuf/compiler/java/java_helpers.cc

@@ -66,15 +66,26 @@ namespace {
 
 const char* kDefaultPackage = "";
 
-// Names that should be avoided as field names.
-// Using them will cause the compiler to generate accessors whose names are
-// colliding with methods defined in base classes.
+// Names that should be avoided (in UpperCamelCase format).
+// Using them will cause the compiler to generate accessors whose names
+// collide with methods defined in base classes.
+// Keep this list in sync with specialFieldNames in
+// java/core/src/main/java/com/google/protobuf/DescriptorMessageInfoFactory.java
 const char* kForbiddenWordList[] = {
-    // message base class:
-    "cached_size",
-    "serialized_size",
     // java.lang.Object:
-    "class",
+    "Class",
+    // com.google.protobuf.MessageLiteOrBuilder:
+    "DefaultInstanceForType",
+    // com.google.protobuf.MessageLite:
+    "ParserForType",
+    "SerializedSize",
+    // com.google.protobuf.MessageOrBuilder:
+    "AllFields",
+    "DescriptorForType",
+    "InitializationErrorString",
+    "UnknownFields",
+    // obsolete. kept for backwards compatibility of generated code
+    "CachedSize",
 };
 
 const std::unordered_set<std::string>* kReservedNames =
@@ -93,7 +104,7 @@ const std::unordered_set<std::string>* kReservedNames =
 
 bool IsForbidden(const std::string& field_name) {
   for (int i = 0; i < GOOGLE_ARRAYSIZE(kForbiddenWordList); ++i) {
-    if (field_name == kForbiddenWordList[i]) {
+    if (UnderscoresToCamelCase(field_name, true) == kForbiddenWordList[i]) {
       return true;
     }
   }

src/google/protobuf/compiler/objectivec/objectivec_generator.cc

@@ -190,10 +190,20 @@ bool ObjectiveCGenerator::GenerateAll(
       // header search path since the generate #import will be more complete.
       generation_options.runtime_import_prefix =
           StripSuffixString(options[i].second, "/");
+    } else if (options[i].first == "default_objc_class_prefix") {
+      // The default objc class prefix to use if specified by the command line 
+      // invocation. The file option is always honored first if one is present.
+      std::string value = options[i].second;
+      if (value.empty()) {
+        *error = "error: default_objc_class_prefix cannot be empty.";
+        return false;
+      }
+      SetDefaultObjcClassPrefix(value);
     } else if (options[i].first == "use_package_as_prefix") {
       // Controls how the symbols should be prefixed to avoid symbols
-      // collisions. The objc_class_prefix file option is always honored, this
-      // is just what to do if that isn't set. The available options are:
+      // collisions. The objc_class_prefix file option is always honored first
+      // followed by the default_objc_class_prefix generator option. This is is just 
+      // what to do if either of these options are not set. The available options are:
       //   "no": Not prefixed (the existing mode).
       //   "yes": Make a prefix out of the proto package.
       bool value = false;

src/google/protobuf/compiler/objectivec/objectivec_helpers.cc

@@ -99,6 +99,9 @@ class PrefixModeStorage {
  public:
   PrefixModeStorage();
 
+  const std::string default_objc_class_prefix() const { return default_objc_class_prefix_; }
+  void set_default_objc_class_prefix(const std::string& default_objc_class_prefix) { default_objc_class_prefix_ = default_objc_class_prefix; }
+
   bool use_package_name() const { return use_package_name_; }
   void set_use_package_name(bool on_or_off) { use_package_name_ = on_or_off; }
 
@@ -116,13 +119,14 @@ class PrefixModeStorage {
 
  private:
   bool use_package_name_;
+  std::string default_objc_class_prefix_;
   std::string exception_path_;
   std::string forced_prefix_;
   std::unordered_set<std::string> exceptions_;
 };
 
 PrefixModeStorage::PrefixModeStorage() {
-  // Even thought there are generation options, have an env back door since some
+  // Even though there are generation options, have an env back door since some
   // of these helpers could be used in other plugins.
 
   use_package_name_ = BoolFromEnvVar("GPB_OBJC_USE_PACKAGE_AS_PREFIX", false);
@@ -169,6 +173,10 @@ PrefixModeStorage g_prefix_mode;
 
 }  // namespace
 
+void SetDefaultObjcClassPrefix(const std::string& default_objc_class_prefix) {
+  g_prefix_mode.set_default_objc_class_prefix(default_objc_class_prefix);
+}
+
 bool UseProtoPackageAsDefaultPrefix() {
   return g_prefix_mode.use_package_name();
 }
@@ -526,11 +534,16 @@ std::string BaseFileName(const FileDescriptor* file) {
 }
 
 std::string FileClassPrefix(const FileDescriptor* file) {
-  // Always honor the file option.
+  // Always honor the file option first.
   if (file->options().has_objc_class_prefix()) {
     return file->options().objc_class_prefix();
   }
 
+  // If a default prefix is passed through objc_opt then accept it.
+  if (!g_prefix_mode.default_objc_class_prefix().empty()) {
+    return g_prefix_mode.default_objc_class_prefix();
+  }
+
   // If package prefix isn't enabled, done.
   if (!g_prefix_mode.use_package_name()) {
     return "";

src/google/protobuf/compiler/objectivec/objectivec_helpers.h

@@ -47,6 +47,9 @@ namespace protobuf {
 namespace compiler {
 namespace objectivec {
 
+// Set the default objc class prefix that should be used. This method is used only
+// when default_objc_class_prefix is passed through objc_opt.
+void PROTOC_EXPORT SetDefaultObjcClassPrefix(const std::string& objc_class_prefix);
 // Get/Set if the proto package should be used to make the default prefix for
 // symbols. This will then impact most of the type naming apis below. It is done
 // as a global to not break any other generator reusing the methods since they
@@ -68,6 +71,7 @@ struct Options {
   std::string generate_for_named_framework;
   std::string named_framework_to_proto_path_mappings_path;
   std::string runtime_import_prefix;
+  std::string default_objc_class_prefix;
   bool prefixes_must_be_registered;
   bool require_prefixes;
 };

src/google/protobuf/compiler/parser_unittest.cc

@@ -2466,7 +2466,9 @@ TEST_F(ParseDescriptorDebugTest, TestMaps) {
 //   *output_field to the descriptor of the field, and *output_index to -1.
 // Returns true if the path was valid, false otherwise.  A gTest failure is
 // recorded before returning false.
-bool FollowPath(const Message& root, const int* path_begin, const int* path_end,
+bool FollowPath(const Message& root,
+                RepeatedField<int>::const_iterator path_begin,
+                RepeatedField<int>::const_iterator path_end,
                 const Message** output_message,
                 const FieldDescriptor** output_field, int* output_index) {
   if (path_begin == path_end) {

src/google/protobuf/compiler/php/php_generator.cc

@@ -58,18 +58,19 @@ const char* const kReservedNames[] = {
     "global",       "goto",         "if",         "implements", "include",
     "include_once", "instanceof",   "insteadof",  "interface",  "isset",
     "list",         "match",        "namespace",  "new",        "or",
-    "print",        "private",    "protected",  "public",     "require",
-    "require_once", "return",     "static",     "switch",     "throw",
-    "trait",        "try",        "unset",      "use",        "var",
-    "while",        "xor",        "yield",      "int",        "float",
-    "bool",         "string",     "true",       "false",      "null",
-    "void",         "iterable"};
+    "parent",       "print",        "private",    "protected",  "public",
+    "require",      "require_once", "return",     "self",       "static",
+    "switch",       "throw",        "trait",      "try",        "unset",
+    "use",          "var",          "while",      "xor",        "yield",
+    "int",          "float",        "bool",       "string",     "true",
+    "false",        "null",         "void",       "iterable"};
 const char* const kValidConstantNames[] = {
     "int",   "float", "bool", "string",   "true",
-    "false", "null",  "void", "iterable",
+    "false", "null",  "void", "iterable", "parent",
+    "self"
 };
-const int kReservedNamesSize = 77;
-const int kValidConstantNamesSize = 9;
+const int kReservedNamesSize = 79;
+const int kValidConstantNamesSize = 11;
 const int kFieldSetter = 1;
 const int kFieldGetter = 2;
 const int kFieldProperty = 3;

src/google/protobuf/compiler/plugin.pb.cc

@@ -252,10 +252,10 @@ Version::Version(const Version& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   suffix_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    suffix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    suffix_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_suffix()) {
-    suffix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_suffix(), 
+    suffix_.Set(from._internal_suffix(), 
       GetArenaForAllocation());
   }
   ::memcpy(&major_, &from.major_,
@@ -267,7 +267,7 @@ Version::Version(const Version& from)
 inline void Version::SharedCtor() {
 suffix_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  suffix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  suffix_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&major_) - reinterpret_cast<char*>(this)),
@@ -286,7 +286,7 @@ Version::~Version() {
 
 inline void Version::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  suffix_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  suffix_.Destroy();
 }
 
 void Version::SetCachedSize(int size) const {
@@ -517,7 +517,6 @@ void Version::InternalSwap(Version* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &suffix_, lhs_arena,
       &other->suffix_, rhs_arena
   );
@@ -572,10 +571,10 @@ CodeGeneratorRequest::CodeGeneratorRequest(const CodeGeneratorRequest& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   parameter_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    parameter_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    parameter_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_parameter()) {
-    parameter_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_parameter(), 
+    parameter_.Set(from._internal_parameter(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_compiler_version()) {
@@ -589,7 +588,7 @@ CodeGeneratorRequest::CodeGeneratorRequest(const CodeGeneratorRequest& from)
 inline void CodeGeneratorRequest::SharedCtor() {
 parameter_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  parameter_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  parameter_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 compiler_version_ = nullptr;
 }
@@ -605,7 +604,7 @@ CodeGeneratorRequest::~CodeGeneratorRequest() {
 
 inline void CodeGeneratorRequest::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  parameter_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  parameter_.Destroy();
   if (this != internal_default_instance()) delete compiler_version_;
 }
 
@@ -864,7 +863,6 @@ void CodeGeneratorRequest::InternalSwap(CodeGeneratorRequest* other) {
   file_to_generate_.InternalSwap(&other->file_to_generate_);
   proto_file_.InternalSwap(&other->proto_file_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &parameter_, lhs_arena,
       &other->parameter_, rhs_arena
   );
@@ -917,26 +915,26 @@ CodeGeneratorResponse_File::CodeGeneratorResponse_File(const CodeGeneratorRespon
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   insertion_point_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    insertion_point_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    insertion_point_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_insertion_point()) {
-    insertion_point_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_insertion_point(), 
+    insertion_point_.Set(from._internal_insertion_point(), 
       GetArenaForAllocation());
   }
   content_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    content_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    content_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_content()) {
-    content_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_content(), 
+    content_.Set(from._internal_content(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_generated_code_info()) {
@@ -950,15 +948,15 @@ CodeGeneratorResponse_File::CodeGeneratorResponse_File(const CodeGeneratorRespon
 inline void CodeGeneratorResponse_File::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 insertion_point_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  insertion_point_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  insertion_point_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 content_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  content_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  content_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 generated_code_info_ = nullptr;
 }
@@ -974,9 +972,9 @@ CodeGeneratorResponse_File::~CodeGeneratorResponse_File() {
 
 inline void CodeGeneratorResponse_File::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  insertion_point_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  content_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  insertion_point_.Destroy();
+  content_.Destroy();
   if (this != internal_default_instance()) delete generated_code_info_;
 }
 
@@ -1234,17 +1232,14 @@ void CodeGeneratorResponse_File::InternalSwap(CodeGeneratorResponse_File* other)
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &insertion_point_, lhs_arena,
       &other->insertion_point_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &content_, lhs_arena,
       &other->content_, rhs_arena
   );
@@ -1284,10 +1279,10 @@ CodeGeneratorResponse::CodeGeneratorResponse(const CodeGeneratorResponse& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   error_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    error_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    error_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_error()) {
-    error_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_error(), 
+    error_.Set(from._internal_error(), 
       GetArenaForAllocation());
   }
   supported_features_ = from.supported_features_;
@@ -1297,7 +1292,7 @@ CodeGeneratorResponse::CodeGeneratorResponse(const CodeGeneratorResponse& from)
 inline void CodeGeneratorResponse::SharedCtor() {
 error_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  error_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  error_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 supported_features_ = uint64_t{0u};
 }
@@ -1313,7 +1308,7 @@ CodeGeneratorResponse::~CodeGeneratorResponse() {
 
 inline void CodeGeneratorResponse::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  error_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  error_.Destroy();
 }
 
 void CodeGeneratorResponse::SetCachedSize(int size) const {
@@ -1525,7 +1520,6 @@ void CodeGeneratorResponse::InternalSwap(CodeGeneratorResponse* other) {
   swap(_has_bits_[0], other->_has_bits_[0]);
   file_.InternalSwap(&other->file_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &error_, lhs_arena,
       &other->error_, rhs_arena
   );

src/google/protobuf/compiler/plugin.pb.h

@@ -1093,7 +1093,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void Version::set_suffix(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000001u;
- suffix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ suffix_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.Version.suffix)
 }
 inline std::string* Version::mutable_suffix() {
@@ -1106,11 +1106,11 @@ inline const std::string& Version::_internal_suffix() const {
 }
 inline void Version::_internal_set_suffix(const std::string& value) {
   _has_bits_[0] |= 0x00000001u;
-  suffix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  suffix_.Set(value, GetArenaForAllocation());
 }
 inline std::string* Version::_internal_mutable_suffix() {
   _has_bits_[0] |= 0x00000001u;
-  return suffix_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return suffix_.Mutable(GetArenaForAllocation());
 }
 inline std::string* Version::release_suffix() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.Version.suffix)
@@ -1118,10 +1118,10 @@ inline std::string* Version::release_suffix() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000001u;
-  auto* p = suffix_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = suffix_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (suffix_.IsDefault()) {
-    suffix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    suffix_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1132,11 +1132,10 @@ inline void Version::set_allocated_suffix(std::string* suffix) {
   } else {
     _has_bits_[0] &= ~0x00000001u;
   }
-  suffix_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), suffix,
-      GetArenaForAllocation());
+  suffix_.SetAllocated(suffix, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (suffix_.IsDefault()) {
-    suffix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    suffix_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.Version.suffix)
@@ -1241,7 +1240,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void CodeGeneratorRequest::set_parameter(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000001u;
- parameter_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ parameter_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorRequest.parameter)
 }
 inline std::string* CodeGeneratorRequest::mutable_parameter() {
@@ -1254,11 +1253,11 @@ inline const std::string& CodeGeneratorRequest::_internal_parameter() const {
 }
 inline void CodeGeneratorRequest::_internal_set_parameter(const std::string& value) {
   _has_bits_[0] |= 0x00000001u;
-  parameter_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  parameter_.Set(value, GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorRequest::_internal_mutable_parameter() {
   _has_bits_[0] |= 0x00000001u;
-  return parameter_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return parameter_.Mutable(GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorRequest::release_parameter() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorRequest.parameter)
@@ -1266,10 +1265,10 @@ inline std::string* CodeGeneratorRequest::release_parameter() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000001u;
-  auto* p = parameter_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = parameter_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (parameter_.IsDefault()) {
-    parameter_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    parameter_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1280,11 +1279,10 @@ inline void CodeGeneratorRequest::set_allocated_parameter(std::string* parameter
   } else {
     _has_bits_[0] &= ~0x00000001u;
   }
-  parameter_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), parameter,
-      GetArenaForAllocation());
+  parameter_.SetAllocated(parameter, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (parameter_.IsDefault()) {
-    parameter_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    parameter_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.CodeGeneratorRequest.parameter)
@@ -1404,7 +1402,7 @@ inline void CodeGeneratorRequest::set_allocated_compiler_version(::PROTOBUF_NAME
   }
   if (compiler_version) {
     ::PROTOBUF_NAMESPACE_ID::Arena* submessage_arena =
-        ::PROTOBUF_NAMESPACE_ID::Arena::InternalHelper<::PROTOBUF_NAMESPACE_ID::compiler::Version>::GetOwningArena(compiler_version);
+        ::PROTOBUF_NAMESPACE_ID::Arena::InternalGetOwningArena(compiler_version);
     if (message_arena != submessage_arena) {
       compiler_version = ::PROTOBUF_NAMESPACE_ID::internal::GetOwnedMessage(
           message_arena, compiler_version, submessage_arena);
@@ -1441,7 +1439,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void CodeGeneratorResponse_File::set_name(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000001u;
- name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ name_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.name)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_name() {
@@ -1454,11 +1452,11 @@ inline const std::string& CodeGeneratorResponse_File::_internal_name() const {
 }
 inline void CodeGeneratorResponse_File::_internal_set_name(const std::string& value) {
   _has_bits_[0] |= 0x00000001u;
-  name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  name_.Set(value, GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::_internal_mutable_name() {
   _has_bits_[0] |= 0x00000001u;
-  return name_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return name_.Mutable(GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::release_name() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.name)
@@ -1466,10 +1464,10 @@ inline std::string* CodeGeneratorResponse_File::release_name() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000001u;
-  auto* p = name_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = name_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (name_.IsDefault()) {
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1480,11 +1478,10 @@ inline void CodeGeneratorResponse_File::set_allocated_name(std::string* name) {
   } else {
     _has_bits_[0] &= ~0x00000001u;
   }
-  name_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), name,
-      GetArenaForAllocation());
+  name_.SetAllocated(name, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (name_.IsDefault()) {
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.CodeGeneratorResponse.File.name)
@@ -1510,7 +1507,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void CodeGeneratorResponse_File::set_insertion_point(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000002u;
- insertion_point_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ insertion_point_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_insertion_point() {
@@ -1523,11 +1520,11 @@ inline const std::string& CodeGeneratorResponse_File::_internal_insertion_point(
 }
 inline void CodeGeneratorResponse_File::_internal_set_insertion_point(const std::string& value) {
   _has_bits_[0] |= 0x00000002u;
-  insertion_point_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  insertion_point_.Set(value, GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::_internal_mutable_insertion_point() {
   _has_bits_[0] |= 0x00000002u;
-  return insertion_point_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return insertion_point_.Mutable(GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::release_insertion_point() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
@@ -1535,10 +1532,10 @@ inline std::string* CodeGeneratorResponse_File::release_insertion_point() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000002u;
-  auto* p = insertion_point_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = insertion_point_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (insertion_point_.IsDefault()) {
-    insertion_point_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    insertion_point_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1549,11 +1546,10 @@ inline void CodeGeneratorResponse_File::set_allocated_insertion_point(std::strin
   } else {
     _has_bits_[0] &= ~0x00000002u;
   }
-  insertion_point_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), insertion_point,
-      GetArenaForAllocation());
+  insertion_point_.SetAllocated(insertion_point, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (insertion_point_.IsDefault()) {
-    insertion_point_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    insertion_point_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
@@ -1579,7 +1575,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void CodeGeneratorResponse_File::set_content(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000004u;
- content_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ content_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.File.content)
 }
 inline std::string* CodeGeneratorResponse_File::mutable_content() {
@@ -1592,11 +1588,11 @@ inline const std::string& CodeGeneratorResponse_File::_internal_content() const
 }
 inline void CodeGeneratorResponse_File::_internal_set_content(const std::string& value) {
   _has_bits_[0] |= 0x00000004u;
-  content_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  content_.Set(value, GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::_internal_mutable_content() {
   _has_bits_[0] |= 0x00000004u;
-  return content_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return content_.Mutable(GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse_File::release_content() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.content)
@@ -1604,10 +1600,10 @@ inline std::string* CodeGeneratorResponse_File::release_content() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000004u;
-  auto* p = content_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = content_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (content_.IsDefault()) {
-    content_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    content_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1618,11 +1614,10 @@ inline void CodeGeneratorResponse_File::set_allocated_content(std::string* conte
   } else {
     _has_bits_[0] &= ~0x00000004u;
   }
-  content_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), content,
-      GetArenaForAllocation());
+  content_.SetAllocated(content, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (content_.IsDefault()) {
-    content_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    content_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.CodeGeneratorResponse.File.content)
@@ -1701,8 +1696,7 @@ inline void CodeGeneratorResponse_File::set_allocated_generated_code_info(::PROT
   }
   if (generated_code_info) {
     ::PROTOBUF_NAMESPACE_ID::Arena* submessage_arena =
-        ::PROTOBUF_NAMESPACE_ID::Arena::InternalHelper<
-            ::PROTOBUF_NAMESPACE_ID::MessageLite>::GetOwningArena(
+        ::PROTOBUF_NAMESPACE_ID::Arena::InternalGetOwningArena(
                 reinterpret_cast<::PROTOBUF_NAMESPACE_ID::MessageLite*>(generated_code_info));
     if (message_arena != submessage_arena) {
       generated_code_info = ::PROTOBUF_NAMESPACE_ID::internal::GetOwnedMessage(
@@ -1740,7 +1734,7 @@ template <typename ArgT0, typename... ArgT>
 inline PROTOBUF_ALWAYS_INLINE
 void CodeGeneratorResponse::set_error(ArgT0&& arg0, ArgT... args) {
  _has_bits_[0] |= 0x00000001u;
- error_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
+ error_.Set(static_cast<ArgT0 &&>(arg0), args..., GetArenaForAllocation());
   // @@protoc_insertion_point(field_set:google.protobuf.compiler.CodeGeneratorResponse.error)
 }
 inline std::string* CodeGeneratorResponse::mutable_error() {
@@ -1753,11 +1747,11 @@ inline const std::string& CodeGeneratorResponse::_internal_error() const {
 }
 inline void CodeGeneratorResponse::_internal_set_error(const std::string& value) {
   _has_bits_[0] |= 0x00000001u;
-  error_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, value, GetArenaForAllocation());
+  error_.Set(value, GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse::_internal_mutable_error() {
   _has_bits_[0] |= 0x00000001u;
-  return error_.Mutable(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, GetArenaForAllocation());
+  return error_.Mutable(GetArenaForAllocation());
 }
 inline std::string* CodeGeneratorResponse::release_error() {
   // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.error)
@@ -1765,10 +1759,10 @@ inline std::string* CodeGeneratorResponse::release_error() {
     return nullptr;
   }
   _has_bits_[0] &= ~0x00000001u;
-  auto* p = error_.ReleaseNonDefault(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), GetArenaForAllocation());
+  auto* p = error_.Release();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (error_.IsDefault()) {
-    error_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    error_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   return p;
@@ -1779,11 +1773,10 @@ inline void CodeGeneratorResponse::set_allocated_error(std::string* error) {
   } else {
     _has_bits_[0] &= ~0x00000001u;
   }
-  error_.SetAllocated(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), error,
-      GetArenaForAllocation());
+  error_.SetAllocated(error, GetArenaForAllocation());
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (error_.IsDefault()) {
-    error_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    error_.Set("", GetArenaForAllocation());
   }
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   // @@protoc_insertion_point(field_set_allocated:google.protobuf.compiler.CodeGeneratorResponse.error)

src/google/protobuf/compiler/subprocess.cc

@@ -73,15 +73,15 @@ static void CloseHandleOrDie(HANDLE handle) {
 
 Subprocess::Subprocess()
     : process_start_error_(ERROR_SUCCESS),
-      child_handle_(NULL),
-      child_stdin_(NULL),
-      child_stdout_(NULL) {}
+      child_handle_(nullptr),
+      child_stdin_(nullptr),
+      child_stdout_(nullptr) {}
 
 Subprocess::~Subprocess() {
-  if (child_stdin_ != NULL) {
+  if (child_stdin_ != nullptr) {
     CloseHandleOrDie(child_stdin_);
   }
-  if (child_stdout_ != NULL) {
+  if (child_stdout_ != nullptr) {
     CloseHandleOrDie(child_stdout_);
   }
 }
@@ -93,10 +93,10 @@ void Subprocess::Start(const std::string& program, SearchMode search_mode) {
   HANDLE stdout_pipe_read;
   HANDLE stdout_pipe_write;
 
-  if (!CreatePipe(&stdin_pipe_read, &stdin_pipe_write, NULL, 0)) {
+  if (!CreatePipe(&stdin_pipe_read, &stdin_pipe_write, nullptr, 0)) {
     GOOGLE_LOG(FATAL) << "CreatePipe: " << Win32ErrorMessage(GetLastError());
   }
-  if (!CreatePipe(&stdout_pipe_read, &stdout_pipe_write, NULL, 0)) {
+  if (!CreatePipe(&stdout_pipe_read, &stdout_pipe_write, nullptr, 0)) {
     GOOGLE_LOG(FATAL) << "CreatePipe: " << Win32ErrorMessage(GetLastError());
   }
 
@@ -134,14 +134,14 @@ void Subprocess::Start(const std::string& program, SearchMode search_mode) {
   // Create the process.
   PROCESS_INFORMATION process_info;
 
-  if (CreateProcessA((search_mode == SEARCH_PATH) ? NULL : program.c_str(),
-                     (search_mode == SEARCH_PATH) ? command_line : NULL,
-                     NULL,  // process security attributes
-                     NULL,  // thread security attributes
+  if (CreateProcessA((search_mode == SEARCH_PATH) ? nullptr : program.c_str(),
+                     (search_mode == SEARCH_PATH) ? command_line : nullptr,
+                     nullptr,  // process security attributes
+                     nullptr,  // thread security attributes
                      TRUE,     // inherit handles?
                      0,        // obscure creation flags
-                     NULL,  // environment (inherit from parent)
-                     NULL,  // current directory (inherit from parent)
+                     nullptr,  // environment (inherit from parent)
+                     nullptr,  // current directory (inherit from parent)
                      &startup_info, &process_info)) {
     child_handle_ = process_info.hProcess;
     CloseHandleOrDie(process_info.hThread);
@@ -165,28 +165,28 @@ bool Subprocess::Communicate(const Message& input, Message* output,
     return false;
   }
 
-  GOOGLE_CHECK(child_handle_ != NULL) << "Must call Start() first.";
+  GOOGLE_CHECK(child_handle_ != nullptr) << "Must call Start() first.";
 
   std::string input_data = input.SerializeAsString();
   std::string output_data;
 
   int input_pos = 0;
 
-  while (child_stdout_ != NULL) {
+  while (child_stdout_ != nullptr) {
     HANDLE handles[2];
     int handle_count = 0;
 
-    if (child_stdin_ != NULL) {
+    if (child_stdin_ != nullptr) {
       handles[handle_count++] = child_stdin_;
     }
-    if (child_stdout_ != NULL) {
+    if (child_stdout_ != nullptr) {
       handles[handle_count++] = child_stdout_;
     }
 
     DWORD wait_result =
         WaitForMultipleObjects(handle_count, handles, FALSE, INFINITE);
 
-    HANDLE signaled_handle = NULL;
+    HANDLE signaled_handle = nullptr;
     if (wait_result >= WAIT_OBJECT_0 &&
         wait_result < WAIT_OBJECT_0 + handle_count) {
       signaled_handle = handles[wait_result - WAIT_OBJECT_0];
@@ -201,7 +201,7 @@ bool Subprocess::Communicate(const Message& input, Message* output,
     if (signaled_handle == child_stdin_) {
       DWORD n;
       if (!WriteFile(child_stdin_, input_data.data() + input_pos,
-                     input_data.size() - input_pos, &n, NULL)) {
+                     input_data.size() - input_pos, &n, nullptr)) {
         // Child closed pipe.  Presumably it will report an error later.
         // Pretend we're done for now.
         input_pos = input_data.size();
@@ -212,27 +212,27 @@ bool Subprocess::Communicate(const Message& input, Message* output,
       if (input_pos == input_data.size()) {
         // We're done writing.  Close.
         CloseHandleOrDie(child_stdin_);
-        child_stdin_ = NULL;
+        child_stdin_ = nullptr;
       }
     } else if (signaled_handle == child_stdout_) {
       char buffer[4096];
       DWORD n;
 
-      if (!ReadFile(child_stdout_, buffer, sizeof(buffer), &n, NULL)) {
+      if (!ReadFile(child_stdout_, buffer, sizeof(buffer), &n, nullptr)) {
         // We're done reading.  Close.
         CloseHandleOrDie(child_stdout_);
-        child_stdout_ = NULL;
+        child_stdout_ = nullptr;
       } else {
         output_data.append(buffer, n);
       }
     }
   }
 
-  if (child_stdin_ != NULL) {
+  if (child_stdin_ != nullptr) {
     // Child did not finish reading input before it closed the output.
     // Presumably it exited with an error.
     CloseHandleOrDie(child_stdin_);
-    child_stdin_ = NULL;
+    child_stdin_ = nullptr;
   }
 
   DWORD wait_result = WaitForSingleObject(child_handle_, INFINITE);
@@ -252,7 +252,7 @@ bool Subprocess::Communicate(const Message& input, Message* output,
   }
 
   CloseHandleOrDie(child_handle_);
-  child_handle_ = NULL;
+  child_handle_ = nullptr;
 
   if (exit_code != 0) {
     *error = strings::Substitute("Plugin failed with status code $0.", exit_code);
@@ -273,9 +273,10 @@ std::string Subprocess::Win32ErrorMessage(DWORD error_code) {
   // WTF?
   FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
                      FORMAT_MESSAGE_IGNORE_INSERTS,
-                 NULL, error_code, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
+                 nullptr, error_code,
+                 MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
                  (LPSTR)&message,  // NOT A BUG!
-                 0, NULL);
+                 0, nullptr);
 
   std::string result = message;
   LocalFree(message);

src/google/protobuf/descriptor.cc

@@ -49,7 +49,6 @@
 
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
-#include <google/protobuf/stubs/stringprintf.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/once.h>
 #include <google/protobuf/any.h>
@@ -58,6 +57,7 @@
 #include <google/protobuf/io/tokenizer.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 #include <google/protobuf/stubs/casts.h>
+#include <google/protobuf/stubs/stringprintf.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/descriptor_database.h>
 #include <google/protobuf/dynamic_message.h>
@@ -1300,10 +1300,6 @@ class FileDescriptorTables {
   bool AddFieldByNumber(FieldDescriptor* field);
   bool AddEnumValueByNumber(EnumValueDescriptor* value);
 
-  // Adds the field to the lowercase_name and camelcase_name maps.  Never
-  // fails because we allow duplicates; the first field by the name wins.
-  void AddFieldByStylizedNames(const FieldDescriptor* field);
-
   // Populates p->first->locations_by_path_ from p->second.
   // Unusual signature dictated by internal::call_once.
   static void BuildLocationsByPath(
@@ -1330,12 +1326,13 @@ class FileDescriptorTables {
   void FieldsByCamelcaseNamesLazyInitInternal() const;
 
   SymbolsByParentSet symbols_by_parent_;
-  mutable FieldsByNameMap fields_by_lowercase_name_;
-  std::unique_ptr<FieldsByNameMap> fields_by_lowercase_name_tmp_;
   mutable internal::once_flag fields_by_lowercase_name_once_;
-  mutable FieldsByNameMap fields_by_camelcase_name_;
-  std::unique_ptr<FieldsByNameMap> fields_by_camelcase_name_tmp_;
   mutable internal::once_flag fields_by_camelcase_name_once_;
+  // Make these fields atomic to avoid race conditions with
+  // GetEstimatedOwnedMemoryBytesSize. Once the pointer is set the map won't
+  // change anymore.
+  mutable std::atomic<const FieldsByNameMap*> fields_by_lowercase_name_{};
+  mutable std::atomic<const FieldsByNameMap*> fields_by_camelcase_name_{};
   FieldsByNumberSet fields_by_number_;  // Not including extensions.
   EnumValuesByNumberSet enum_values_by_number_;
   mutable EnumValuesByNumberSet unknown_enum_values_by_number_
@@ -1373,11 +1370,12 @@ DescriptorPool::Tables::Tables() {
 
 DescriptorPool::Tables::~Tables() { GOOGLE_DCHECK(checkpoints_.empty()); }
 
-FileDescriptorTables::FileDescriptorTables()
-    : fields_by_lowercase_name_tmp_(new FieldsByNameMap()),
-      fields_by_camelcase_name_tmp_(new FieldsByNameMap()) {}
+FileDescriptorTables::FileDescriptorTables() {}
 
-FileDescriptorTables::~FileDescriptorTables() {}
+FileDescriptorTables::~FileDescriptorTables() {
+  delete fields_by_lowercase_name_.load(std::memory_order_acquire);
+  delete fields_by_camelcase_name_.load(std::memory_order_acquire);
+}
 
 inline const FileDescriptorTables& FileDescriptorTables::GetEmptyInstance() {
   static auto file_descriptor_tables =
@@ -1520,13 +1518,14 @@ void FileDescriptorTables::FieldsByLowercaseNamesLazyInitStatic(
 }
 
 void FileDescriptorTables::FieldsByLowercaseNamesLazyInitInternal() const {
+  auto* map = new FieldsByNameMap;
   for (Symbol symbol : symbols_by_parent_) {
     const FieldDescriptor* field = symbol.field_descriptor();
     if (!field) continue;
-    PointerStringPair lowercase_key(FindParentForFieldsByMap(field),
-                                    field->lowercase_name().c_str());
-    InsertIfNotPresent(&fields_by_lowercase_name_, lowercase_key, field);
+    (*map)[{FindParentForFieldsByMap(field), field->lowercase_name().c_str()}] =
+        field;
   }
+  fields_by_lowercase_name_.store(map, std::memory_order_release);
 }
 
 inline const FieldDescriptor* FileDescriptorTables::FindFieldByLowercaseName(
@@ -1534,7 +1533,8 @@ inline const FieldDescriptor* FileDescriptorTables::FindFieldByLowercaseName(
   internal::call_once(
       fields_by_lowercase_name_once_,
       &FileDescriptorTables::FieldsByLowercaseNamesLazyInitStatic, this);
-  return FindPtrOrNull(fields_by_lowercase_name_,
+  return FindPtrOrNull(
+      *fields_by_lowercase_name_.load(std::memory_order_acquire),
       PointerStringPair(parent, lowercase_name));
 }
 
@@ -1544,13 +1544,14 @@ void FileDescriptorTables::FieldsByCamelcaseNamesLazyInitStatic(
 }
 
 void FileDescriptorTables::FieldsByCamelcaseNamesLazyInitInternal() const {
+  auto* map = new FieldsByNameMap;
   for (Symbol symbol : symbols_by_parent_) {
     const FieldDescriptor* field = symbol.field_descriptor();
     if (!field) continue;
-    PointerStringPair camelcase_key(FindParentForFieldsByMap(field),
-                                    field->camelcase_name().c_str());
-    InsertIfNotPresent(&fields_by_camelcase_name_, camelcase_key, field);
+    (*map)[{FindParentForFieldsByMap(field), field->camelcase_name().c_str()}] =
+        field;
   }
+  fields_by_camelcase_name_.store(map, std::memory_order_release);
 }
 
 inline const FieldDescriptor* FileDescriptorTables::FindFieldByCamelcaseName(
@@ -1558,7 +1559,8 @@ inline const FieldDescriptor* FileDescriptorTables::FindFieldByCamelcaseName(
   internal::call_once(
       fields_by_camelcase_name_once_,
       FileDescriptorTables::FieldsByCamelcaseNamesLazyInitStatic, this);
-  return FindPtrOrNull(fields_by_camelcase_name_,
+  return FindPtrOrNull(
+      *fields_by_camelcase_name_.load(std::memory_order_acquire),
       PointerStringPair(parent, camelcase_name));
 }
 
@@ -1619,8 +1621,8 @@ FileDescriptorTables::FindEnumValueByNumberCreatingIfUnknown(
     // EnumDescriptor (it's not a part of the enum as originally defined), but
     // we do insert it into the table so that we can return the same pointer
     // later.
-    std::string enum_value_name = StringPrintf("UNKNOWN_ENUM_VALUE_%s_%d",
-                                               parent->name().c_str(), number);
+    std::string enum_value_name = StringPrintf(
+        "UNKNOWN_ENUM_VALUE_%s_%d", parent->name().c_str(), number);
     auto* pool = DescriptorPool::generated_pool();
     auto* tables = const_cast<DescriptorPool::Tables*>(pool->tables_.get());
     internal::FlatAllocator alloc;
@@ -1689,39 +1691,7 @@ bool DescriptorPool::Tables::AddFile(const FileDescriptor* file) {
   }
 }
 
-void FileDescriptorTables::FinalizeTables() {
-  // Clean up the temporary maps used by AddFieldByStylizedNames().
-  fields_by_lowercase_name_tmp_ = nullptr;
-  fields_by_camelcase_name_tmp_ = nullptr;
-}
-
-void FileDescriptorTables::AddFieldByStylizedNames(
-    const FieldDescriptor* field) {
-  const void* parent = FindParentForFieldsByMap(field);
-
-  // We want fields_by_{lower,camel}case_name_ to be lazily built, but
-  // cross-link order determines which entry will be present in the case of a
-  // conflict. So we use the temporary maps that get destroyed after
-  // BuildFileImpl() to detect the conflicts, and only store the conflicts in
-  // the map that will persist. We will then lazily populate the rest of the
-  // entries from fields_by_number_.
-
-  PointerStringPair lowercase_key(parent, field->lowercase_name().c_str());
-  if (!InsertIfNotPresent(fields_by_lowercase_name_tmp_.get(),
-                               lowercase_key, field)) {
-    InsertIfNotPresent(
-        &fields_by_lowercase_name_, lowercase_key,
-        FindPtrOrNull(*fields_by_lowercase_name_tmp_, lowercase_key));
-  }
-
-  PointerStringPair camelcase_key(parent, field->camelcase_name().c_str());
-  if (!InsertIfNotPresent(fields_by_camelcase_name_tmp_.get(),
-                               camelcase_key, field)) {
-    InsertIfNotPresent(
-        &fields_by_camelcase_name_, camelcase_key,
-        FindPtrOrNull(*fields_by_camelcase_name_tmp_, camelcase_key));
-  }
-}
+void FileDescriptorTables::FinalizeTables() {}
 
 bool FileDescriptorTables::AddFieldByNumber(FieldDescriptor* field) {
   // Skip fields that are at the start of the sequence.
@@ -6271,9 +6241,6 @@ void DescriptorBuilder::CrossLinkField(FieldDescriptor* field,
     field->options_ = &FieldOptions::default_instance();
   }
 
-  // Add the field to the lowercase-name and camelcase-name tables.
-  file_tables_->AddFieldByStylizedNames(field);
-
   if (proto.has_extendee()) {
     Symbol extendee =
         LookupSymbol(proto.extendee(), field->full_name(),

src/google/protobuf/descriptor.pb.cc

@@ -1506,26 +1506,26 @@ FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   package_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    package_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_package()) {
-    package_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_package(), 
+    package_.Set(from._internal_package(), 
       GetArenaForAllocation());
   }
   syntax_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    syntax_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    syntax_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_syntax()) {
-    syntax_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_syntax(), 
+    syntax_.Set(from._internal_syntax(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -1544,15 +1544,15 @@ FileDescriptorProto::FileDescriptorProto(const FileDescriptorProto& from)
 inline void FileDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 package_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  package_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 syntax_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  syntax_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  syntax_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
@@ -1571,9 +1571,9 @@ FileDescriptorProto::~FileDescriptorProto() {
 
 inline void FileDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  syntax_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  package_.Destroy();
+  syntax_.Destroy();
   if (this != internal_default_instance()) delete options_;
   if (this != internal_default_instance()) delete source_code_info_;
 }
@@ -2102,17 +2102,14 @@ void FileDescriptorProto::InternalSwap(FileDescriptorProto* other) {
   public_dependency_.InternalSwap(&other->public_dependency_);
   weak_dependency_.InternalSwap(&other->weak_dependency_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &package_, lhs_arena,
       &other->package_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &syntax_, lhs_arena,
       &other->syntax_, rhs_arena
   );
@@ -2682,10 +2679,10 @@ DescriptorProto::DescriptorProto(const DescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -2699,7 +2696,7 @@ DescriptorProto::DescriptorProto(const DescriptorProto& from)
 inline void DescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 options_ = nullptr;
 }
@@ -2715,7 +2712,7 @@ DescriptorProto::~DescriptorProto() {
 
 inline void DescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -3173,7 +3170,6 @@ void DescriptorProto::InternalSwap(DescriptorProto* other) {
   reserved_range_.InternalSwap(&other->reserved_range_);
   reserved_name_.InternalSwap(&other->reserved_name_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
@@ -3443,42 +3439,42 @@ FieldDescriptorProto::FieldDescriptorProto(const FieldDescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   extendee_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    extendee_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    extendee_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_extendee()) {
-    extendee_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_extendee(), 
+    extendee_.Set(from._internal_extendee(), 
       GetArenaForAllocation());
   }
   type_name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    type_name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    type_name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_type_name()) {
-    type_name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_type_name(), 
+    type_name_.Set(from._internal_type_name(), 
       GetArenaForAllocation());
   }
   default_value_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    default_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    default_value_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_default_value()) {
-    default_value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_default_value(), 
+    default_value_.Set(from._internal_default_value(), 
       GetArenaForAllocation());
   }
   json_name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    json_name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    json_name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_json_name()) {
-    json_name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_json_name(), 
+    json_name_.Set(from._internal_json_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -3495,23 +3491,23 @@ FieldDescriptorProto::FieldDescriptorProto(const FieldDescriptorProto& from)
 inline void FieldDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 extendee_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  extendee_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  extendee_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 type_name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  type_name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  type_name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 default_value_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  default_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  default_value_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 json_name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  json_name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  json_name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
@@ -3532,11 +3528,11 @@ FieldDescriptorProto::~FieldDescriptorProto() {
 
 inline void FieldDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  extendee_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  type_name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  default_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  json_name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  extendee_.Destroy();
+  type_name_.Destroy();
+  default_value_.Destroy();
+  json_name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -4010,27 +4006,22 @@ void FieldDescriptorProto::InternalSwap(FieldDescriptorProto* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &extendee_, lhs_arena,
       &other->extendee_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &type_name_, lhs_arena,
       &other->type_name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &default_value_, lhs_arena,
       &other->default_value_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &json_name_, lhs_arena,
       &other->json_name_, rhs_arena
   );
@@ -4080,10 +4071,10 @@ OneofDescriptorProto::OneofDescriptorProto(const OneofDescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -4097,7 +4088,7 @@ OneofDescriptorProto::OneofDescriptorProto(const OneofDescriptorProto& from)
 inline void OneofDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 options_ = nullptr;
 }
@@ -4113,7 +4104,7 @@ OneofDescriptorProto::~OneofDescriptorProto() {
 
 inline void OneofDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -4304,7 +4295,6 @@ void OneofDescriptorProto::InternalSwap(OneofDescriptorProto* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
@@ -4583,10 +4573,10 @@ EnumDescriptorProto::EnumDescriptorProto(const EnumDescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -4600,7 +4590,7 @@ EnumDescriptorProto::EnumDescriptorProto(const EnumDescriptorProto& from)
 inline void EnumDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 options_ = nullptr;
 }
@@ -4616,7 +4606,7 @@ EnumDescriptorProto::~EnumDescriptorProto() {
 
 inline void EnumDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -4909,7 +4899,6 @@ void EnumDescriptorProto::InternalSwap(EnumDescriptorProto* other) {
   reserved_range_.InternalSwap(&other->reserved_range_);
   reserved_name_.InternalSwap(&other->reserved_name_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
@@ -4955,10 +4944,10 @@ EnumValueDescriptorProto::EnumValueDescriptorProto(const EnumValueDescriptorProt
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -4973,7 +4962,7 @@ EnumValueDescriptorProto::EnumValueDescriptorProto(const EnumValueDescriptorProt
 inline void EnumValueDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
@@ -4992,7 +4981,7 @@ EnumValueDescriptorProto::~EnumValueDescriptorProto() {
 
 inline void EnumValueDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -5208,7 +5197,6 @@ void EnumValueDescriptorProto::InternalSwap(EnumValueDescriptorProto* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
@@ -5258,10 +5246,10 @@ ServiceDescriptorProto::ServiceDescriptorProto(const ServiceDescriptorProto& fro
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -5275,7 +5263,7 @@ ServiceDescriptorProto::ServiceDescriptorProto(const ServiceDescriptorProto& fro
 inline void ServiceDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 options_ = nullptr;
 }
@@ -5291,7 +5279,7 @@ ServiceDescriptorProto::~ServiceDescriptorProto() {
 
 inline void ServiceDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -5515,7 +5503,6 @@ void ServiceDescriptorProto::InternalSwap(ServiceDescriptorProto* other) {
   swap(_has_bits_[0], other->_has_bits_[0]);
   method_.InternalSwap(&other->method_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
@@ -5570,26 +5557,26 @@ MethodDescriptorProto::MethodDescriptorProto(const MethodDescriptorProto& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name()) {
-    name_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name(), 
+    name_.Set(from._internal_name(), 
       GetArenaForAllocation());
   }
   input_type_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    input_type_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    input_type_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_input_type()) {
-    input_type_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_input_type(), 
+    input_type_.Set(from._internal_input_type(), 
       GetArenaForAllocation());
   }
   output_type_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    output_type_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    output_type_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_output_type()) {
-    output_type_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_output_type(), 
+    output_type_.Set(from._internal_output_type(), 
       GetArenaForAllocation());
   }
   if (from._internal_has_options()) {
@@ -5606,15 +5593,15 @@ MethodDescriptorProto::MethodDescriptorProto(const MethodDescriptorProto& from)
 inline void MethodDescriptorProto::SharedCtor() {
 name_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 input_type_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  input_type_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  input_type_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 output_type_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  output_type_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  output_type_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&options_) - reinterpret_cast<char*>(this)),
@@ -5633,9 +5620,9 @@ MethodDescriptorProto::~MethodDescriptorProto() {
 
 inline void MethodDescriptorProto::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  input_type_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  output_type_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_.Destroy();
+  input_type_.Destroy();
+  output_type_.Destroy();
   if (this != internal_default_instance()) delete options_;
 }
 
@@ -5946,17 +5933,14 @@ void MethodDescriptorProto::InternalSwap(MethodDescriptorProto* other) {
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_, lhs_arena,
       &other->name_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &input_type_, lhs_arena,
       &other->input_type_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &output_type_, lhs_arena,
       &other->output_type_, rhs_arena
   );
@@ -6057,82 +6041,82 @@ FileOptions::FileOptions(const FileOptions& from)
   _extensions_.MergeFrom(internal_default_instance(), from._extensions_);
   java_package_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    java_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    java_package_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_java_package()) {
-    java_package_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_java_package(), 
+    java_package_.Set(from._internal_java_package(), 
       GetArenaForAllocation());
   }
   java_outer_classname_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    java_outer_classname_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    java_outer_classname_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_java_outer_classname()) {
-    java_outer_classname_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_java_outer_classname(), 
+    java_outer_classname_.Set(from._internal_java_outer_classname(), 
       GetArenaForAllocation());
   }
   go_package_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    go_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    go_package_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_go_package()) {
-    go_package_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_go_package(), 
+    go_package_.Set(from._internal_go_package(), 
       GetArenaForAllocation());
   }
   objc_class_prefix_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    objc_class_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    objc_class_prefix_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_objc_class_prefix()) {
-    objc_class_prefix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_objc_class_prefix(), 
+    objc_class_prefix_.Set(from._internal_objc_class_prefix(), 
       GetArenaForAllocation());
   }
   csharp_namespace_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    csharp_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    csharp_namespace_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_csharp_namespace()) {
-    csharp_namespace_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_csharp_namespace(), 
+    csharp_namespace_.Set(from._internal_csharp_namespace(), 
       GetArenaForAllocation());
   }
   swift_prefix_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    swift_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    swift_prefix_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_swift_prefix()) {
-    swift_prefix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_swift_prefix(), 
+    swift_prefix_.Set(from._internal_swift_prefix(), 
       GetArenaForAllocation());
   }
   php_class_prefix_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    php_class_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    php_class_prefix_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_php_class_prefix()) {
-    php_class_prefix_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_php_class_prefix(), 
+    php_class_prefix_.Set(from._internal_php_class_prefix(), 
       GetArenaForAllocation());
   }
   php_namespace_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    php_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    php_namespace_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_php_namespace()) {
-    php_namespace_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_php_namespace(), 
+    php_namespace_.Set(from._internal_php_namespace(), 
       GetArenaForAllocation());
   }
   php_metadata_namespace_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    php_metadata_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    php_metadata_namespace_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_php_metadata_namespace()) {
-    php_metadata_namespace_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_php_metadata_namespace(), 
+    php_metadata_namespace_.Set(from._internal_php_metadata_namespace(), 
       GetArenaForAllocation());
   }
   ruby_package_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    ruby_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    ruby_package_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_ruby_package()) {
-    ruby_package_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_ruby_package(), 
+    ruby_package_.Set(from._internal_ruby_package(), 
       GetArenaForAllocation());
   }
   ::memcpy(&java_multiple_files_, &from.java_multiple_files_,
@@ -6144,43 +6128,43 @@ FileOptions::FileOptions(const FileOptions& from)
 inline void FileOptions::SharedCtor() {
 java_package_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  java_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  java_package_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 java_outer_classname_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  java_outer_classname_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  java_outer_classname_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 go_package_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  go_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  go_package_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 objc_class_prefix_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  objc_class_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  objc_class_prefix_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 csharp_namespace_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  csharp_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  csharp_namespace_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 swift_prefix_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  swift_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  swift_prefix_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 php_class_prefix_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  php_class_prefix_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  php_class_prefix_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 php_namespace_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  php_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  php_namespace_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 php_metadata_namespace_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  php_metadata_namespace_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  php_metadata_namespace_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ruby_package_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  ruby_package_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  ruby_package_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&java_multiple_files_) - reinterpret_cast<char*>(this)),
@@ -6201,16 +6185,16 @@ FileOptions::~FileOptions() {
 
 inline void FileOptions::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  java_package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  java_outer_classname_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  go_package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  objc_class_prefix_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  csharp_namespace_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  swift_prefix_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  php_class_prefix_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  php_namespace_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  php_metadata_namespace_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  ruby_package_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  java_package_.Destroy();
+  java_outer_classname_.Destroy();
+  go_package_.Destroy();
+  objc_class_prefix_.Destroy();
+  csharp_namespace_.Destroy();
+  swift_prefix_.Destroy();
+  php_class_prefix_.Destroy();
+  php_namespace_.Destroy();
+  php_metadata_namespace_.Destroy();
+  ruby_package_.Destroy();
 }
 
 void FileOptions::SetCachedSize(int size) const {
@@ -6994,52 +6978,42 @@ void FileOptions::InternalSwap(FileOptions* other) {
   swap(_has_bits_[0], other->_has_bits_[0]);
   uninterpreted_option_.InternalSwap(&other->uninterpreted_option_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &java_package_, lhs_arena,
       &other->java_package_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &java_outer_classname_, lhs_arena,
       &other->java_outer_classname_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &go_package_, lhs_arena,
       &other->go_package_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &objc_class_prefix_, lhs_arena,
       &other->objc_class_prefix_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &csharp_namespace_, lhs_arena,
       &other->csharp_namespace_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &swift_prefix_, lhs_arena,
       &other->swift_prefix_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &php_class_prefix_, lhs_arena,
       &other->php_class_prefix_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &php_namespace_, lhs_arena,
       &other->php_namespace_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &php_metadata_namespace_, lhs_arena,
       &other->php_metadata_namespace_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &ruby_package_, lhs_arena,
       &other->ruby_package_, rhs_arena
   );
@@ -9097,10 +9071,10 @@ UninterpretedOption_NamePart::UninterpretedOption_NamePart(const UninterpretedOp
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   name_part_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    name_part_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    name_part_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_name_part()) {
-    name_part_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_name_part(), 
+    name_part_.Set(from._internal_name_part(), 
       GetArenaForAllocation());
   }
   is_extension_ = from.is_extension_;
@@ -9110,7 +9084,7 @@ UninterpretedOption_NamePart::UninterpretedOption_NamePart(const UninterpretedOp
 inline void UninterpretedOption_NamePart::SharedCtor() {
 name_part_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  name_part_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  name_part_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 is_extension_ = false;
 }
@@ -9126,7 +9100,7 @@ UninterpretedOption_NamePart::~UninterpretedOption_NamePart() {
 
 inline void UninterpretedOption_NamePart::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  name_part_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  name_part_.Destroy();
 }
 
 void UninterpretedOption_NamePart::SetCachedSize(int size) const {
@@ -9323,7 +9297,6 @@ void UninterpretedOption_NamePart::InternalSwap(UninterpretedOption_NamePart* ot
   _internal_metadata_.InternalSwap(&other->_internal_metadata_);
   swap(_has_bits_[0], other->_has_bits_[0]);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &name_part_, lhs_arena,
       &other->name_part_, rhs_arena
   );
@@ -9375,26 +9348,26 @@ UninterpretedOption::UninterpretedOption(const UninterpretedOption& from)
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   identifier_value_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    identifier_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    identifier_value_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_identifier_value()) {
-    identifier_value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_identifier_value(), 
+    identifier_value_.Set(from._internal_identifier_value(), 
       GetArenaForAllocation());
   }
   string_value_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    string_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    string_value_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_string_value()) {
-    string_value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_string_value(), 
+    string_value_.Set(from._internal_string_value(), 
       GetArenaForAllocation());
   }
   aggregate_value_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    aggregate_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    aggregate_value_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_aggregate_value()) {
-    aggregate_value_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_aggregate_value(), 
+    aggregate_value_.Set(from._internal_aggregate_value(), 
       GetArenaForAllocation());
   }
   ::memcpy(&positive_int_value_, &from.positive_int_value_,
@@ -9406,15 +9379,15 @@ UninterpretedOption::UninterpretedOption(const UninterpretedOption& from)
 inline void UninterpretedOption::SharedCtor() {
 identifier_value_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  identifier_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  identifier_value_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 string_value_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  string_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  string_value_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 aggregate_value_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  aggregate_value_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  aggregate_value_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&positive_int_value_) - reinterpret_cast<char*>(this)),
@@ -9433,9 +9406,9 @@ UninterpretedOption::~UninterpretedOption() {
 
 inline void UninterpretedOption::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  identifier_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  string_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  aggregate_value_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  identifier_value_.Destroy();
+  string_value_.Destroy();
+  aggregate_value_.Destroy();
 }
 
 void UninterpretedOption::SetCachedSize(int size) const {
@@ -9764,17 +9737,14 @@ void UninterpretedOption::InternalSwap(UninterpretedOption* other) {
   swap(_has_bits_[0], other->_has_bits_[0]);
   name_.InternalSwap(&other->name_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &identifier_value_, lhs_arena,
       &other->identifier_value_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &string_value_, lhs_arena,
       &other->string_value_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &aggregate_value_, lhs_arena,
       &other->aggregate_value_, rhs_arena
   );
@@ -9823,18 +9793,18 @@ SourceCodeInfo_Location::SourceCodeInfo_Location(const SourceCodeInfo_Location&
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   leading_comments_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    leading_comments_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    leading_comments_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_leading_comments()) {
-    leading_comments_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_leading_comments(), 
+    leading_comments_.Set(from._internal_leading_comments(), 
       GetArenaForAllocation());
   }
   trailing_comments_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    trailing_comments_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    trailing_comments_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_trailing_comments()) {
-    trailing_comments_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_trailing_comments(), 
+    trailing_comments_.Set(from._internal_trailing_comments(), 
       GetArenaForAllocation());
   }
   // @@protoc_insertion_point(copy_constructor:google.protobuf.SourceCodeInfo.Location)
@@ -9843,11 +9813,11 @@ SourceCodeInfo_Location::SourceCodeInfo_Location(const SourceCodeInfo_Location&
 inline void SourceCodeInfo_Location::SharedCtor() {
 leading_comments_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  leading_comments_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  leading_comments_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 trailing_comments_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  trailing_comments_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  trailing_comments_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 }
 
@@ -9862,8 +9832,8 @@ SourceCodeInfo_Location::~SourceCodeInfo_Location() {
 
 inline void SourceCodeInfo_Location::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  leading_comments_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
-  trailing_comments_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  leading_comments_.Destroy();
+  trailing_comments_.Destroy();
 }
 
 void SourceCodeInfo_Location::SetCachedSize(int size) const {
@@ -10168,12 +10138,10 @@ void SourceCodeInfo_Location::InternalSwap(SourceCodeInfo_Location* other) {
   span_.InternalSwap(&other->span_);
   leading_detached_comments_.InternalSwap(&other->leading_detached_comments_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &leading_comments_, lhs_arena,
       &other->leading_comments_, rhs_arena
   );
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &trailing_comments_, lhs_arena,
       &other->trailing_comments_, rhs_arena
   );
@@ -10393,10 +10361,10 @@ GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(const GeneratedCodeIn
   _internal_metadata_.MergeFrom<::PROTOBUF_NAMESPACE_ID::UnknownFieldSet>(from._internal_metadata_);
   source_file_.InitDefault();
   #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-    source_file_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+    source_file_.Set("", GetArenaForAllocation());
   #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
   if (from._internal_has_source_file()) {
-    source_file_.Set(::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::EmptyDefault{}, from._internal_source_file(), 
+    source_file_.Set(from._internal_source_file(), 
       GetArenaForAllocation());
   }
   ::memcpy(&begin_, &from.begin_,
@@ -10408,7 +10376,7 @@ GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(const GeneratedCodeIn
 inline void GeneratedCodeInfo_Annotation::SharedCtor() {
 source_file_.InitDefault();
 #ifdef PROTOBUF_FORCE_COPY_DEFAULT_STRING
-  source_file_.Set(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(), "", GetArenaForAllocation());
+  source_file_.Set("", GetArenaForAllocation());
 #endif // PROTOBUF_FORCE_COPY_DEFAULT_STRING
 ::memset(reinterpret_cast<char*>(this) + static_cast<size_t>(
     reinterpret_cast<char*>(&begin_) - reinterpret_cast<char*>(this)),
@@ -10427,7 +10395,7 @@ GeneratedCodeInfo_Annotation::~GeneratedCodeInfo_Annotation() {
 
 inline void GeneratedCodeInfo_Annotation::SharedDtor() {
   GOOGLE_DCHECK(GetArenaForAllocation() == nullptr);
-  source_file_.DestroyNoArena(&::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited());
+  source_file_.Destroy();
 }
 
 void GeneratedCodeInfo_Annotation::SetCachedSize(int size) const {
@@ -10672,7 +10640,6 @@ void GeneratedCodeInfo_Annotation::InternalSwap(GeneratedCodeInfo_Annotation* ot
   swap(_has_bits_[0], other->_has_bits_[0]);
   path_.InternalSwap(&other->path_);
   ::PROTOBUF_NAMESPACE_ID::internal::ArenaStringPtr::InternalSwap(
-      &::PROTOBUF_NAMESPACE_ID::internal::GetEmptyStringAlreadyInited(),
       &source_file_, lhs_arena,
       &other->source_file_, rhs_arena
   );