Merge tag 'refs/tags/sync-piper' into sync-stage

benchmarks/java/src/main/java/com/google/protobuf/ProtoCaliperBenchmark.java

@@ -151,7 +151,7 @@ public class ProtoCaliperBenchmark {
     }
   }
 
-  @SuppressWarnings("IgnoredPureGetter")
+  @SuppressWarnings({"IgnoredPureGetter", "CheckReturnValue"})
   @Benchmark
   void serializeToByteArray(int reps) throws IOException {
     if (sampleMessageList.size() == 0) {

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

@@ -59,6 +59,7 @@ import java.io.OutputStream;
  *
  * @author kenton@google.com Kenton Varda
  */
+@CheckReturnValue
 public interface MessageLite extends MessageLiteOrBuilder {
 
   /**
@@ -138,6 +139,7 @@ public interface MessageLite extends MessageLiteOrBuilder {
   /** Abstract interface implemented by Protocol Message builders. */
   interface Builder extends MessageLiteOrBuilder, Cloneable {
     /** Resets all fields to their default values. */
+    @CanIgnoreReturnValue
     Builder clear();
 
     /**
@@ -181,11 +183,12 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * <p>Note: The caller should call {@link CodedInputStream#checkLastTagWas(int)} after calling
      * this to verify that the last tag seen was the appropriate end-group tag, or zero for EOF.
      *
-     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct according
+     *     to the protobuf wire format specification. The data is corrupt, incomplete, or was never
+     *     a protobuf in the first place.
      * @throws IOException an I/O error reading from the stream
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(CodedInputStream input) throws IOException;
 
     /**
@@ -193,11 +196,12 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * that you want to be able to parse must be registered in {@code extensionRegistry}. Extensions
      * not in the registry will be treated as unknown fields.
      *
-     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct according
+     *     to the protobuf wire format specification. The data is corrupt, incomplete, or was never
+     *     a protobuf in the first place.
      * @throws IOException an I/O error reading from the stream
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
         throws IOException;
 
@@ -209,10 +213,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
 
     /**
@@ -220,10 +225,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException;
 
@@ -232,10 +238,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
 
     /**
@@ -243,10 +250,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
 
     /**
@@ -254,10 +262,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException;
 
@@ -266,10 +275,11 @@ public interface MessageLite extends MessageLiteOrBuilder {
      * is just a small wrapper around {@link #mergeFrom(CodedInputStream,ExtensionRegistryLite)}.
      *
      * @throws InvalidProtocolBufferException the bytes in data are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     *     according to the protobuf wire format specification. The data is corrupt, incomplete, or
+     *     was never a protobuf in the first place.
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException;
 
@@ -283,12 +293,13 @@ public interface MessageLite extends MessageLiteOrBuilder {
      *
      * <p>Despite usually reading the entire input, this does not close the stream.
      *
-     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct according
+     *     to the protobuf wire format specification. The data is corrupt, incomplete, or was never
+     *     a protobuf in the first place.
      * @throws IOException an I/O error reading from the stream
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(InputStream input) throws IOException;
 
     /**
@@ -298,6 +309,7 @@ public interface MessageLite extends MessageLiteOrBuilder {
      *
      * @return this
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
         throws IOException;
 
@@ -317,6 +329,7 @@ public interface MessageLite extends MessageLiteOrBuilder {
      *
      * <p>This is equivalent to the {@code Message::MergeFrom} method in C++.
      */
+    @CanIgnoreReturnValue
     Builder mergeFrom(MessageLite other);
 
     /**
@@ -326,11 +339,12 @@ public interface MessageLite extends MessageLiteOrBuilder {
      *
      * @return true if successful, or false if the stream is at EOF when the method starts. Any
      *     other error (including reaching EOF during parsing) causes an exception to be thrown.
-     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct according
+     *     to the protobuf wire format specification. The data is corrupt, incomplete, or was never
+     *     a protobuf in the first place.
      * @throws IOException an I/O error reading from the stream
      */
+    @CanIgnoreReturnValue // TODO(kak): should this be @CheckReturnValue instead?
     boolean mergeDelimitedFrom(InputStream input) throws IOException;
 
     /**
@@ -338,11 +352,12 @@ public interface MessageLite extends MessageLiteOrBuilder {
      *
      * @return true if successful, or false if the stream is at EOF when the method starts. Any
      *     other error (including reaching EOF during parsing) causes an exception to be thrown.
-     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct
-     *     according to the protobuf wire format specification. The data is corrupt, incomplete,
-     *     or was never a protobuf in the first place.
+     * @throws InvalidProtocolBufferException the bytes read are not syntactically correct according
+     *     to the protobuf wire format specification. The data is corrupt, incomplete, or was never
+     *     a protobuf in the first place.
      * @throws IOException an I/O error reading from the stream
      */
+    @CanIgnoreReturnValue // TODO(kak): should this be @CheckReturnValue instead?
     boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
         throws IOException;
   }

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

@@ -36,6 +36,7 @@ package com.google.protobuf;
  *
  * @author jonp@google.com (Jon Perlow)
  */
+@CheckReturnValue
 public interface MessageLiteOrBuilder {
   /**
    * Get an instance of the type with no fields set. Because no fields are set, all getters for

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

@@ -1529,7 +1529,7 @@ public class GeneratedMessageTest {
       assertThat(builder.getFooInt()).isEqualTo(123);
       TestOneof2 message = builder.buildPartial();
       assertThat(message.hasFooInt()).isTrue();
-      assertThat(123).isEqualTo(message.getFooInt());
+      assertThat(message.getFooInt()).isEqualTo(123);
 
       assertThat(builder.clearFooInt().hasFooInt()).isFalse();
       TestOneof2 message2 = builder.build();

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

@@ -235,6 +235,7 @@ import protobuf_unittest.UnittestProto.TestRequired;
 import protobuf_unittest.UnittestProto.TestUnpackedTypes;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.RandomAccessFile;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -3842,7 +3843,11 @@ public final class TestUtil {
 
   private static ByteString readBytesFromResource(String name) {
     try {
-      return ByteString.readFrom(TestUtil.class.getResourceAsStream(name));
+      InputStream in = TestUtil.class.getResourceAsStream(name);
+      if (in == null) { //
+        throw new RuntimeException("Tests data file " + name + " is missing.");
+      }
+      return ByteString.readFrom(in);
     } catch (IOException e) {
       throw new RuntimeException(e);
     }

src/google/protobuf/arena.h

@@ -315,6 +315,15 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
                              static_cast<Args&&>(args)...);
   }
 
+  // API to delete any objects not on an arena.  This can be used to safely
+  // clean up messages or repeated fields without knowing whether or not they're
+  // owned by an arena.  The pointer passed to this function should not be used
+  // again.
+  template <typename T>
+  PROTOBUF_ALWAYS_INLINE static void Destroy(T* obj) {
+    if (InternalGetOwningArena(obj) == nullptr) delete obj;
+  }
+
   // Allocates memory with the specific size and alignment.
   void* AllocateAligned(size_t size, size_t align = 8) {
     if (align <= 8) {
@@ -411,8 +420,23 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
   template <typename T>
   class InternalHelper {
    private:
-    // Provides access to protected GetOwningArena to generated messages.
-    static Arena* GetOwningArena(const T* p) { return p->GetOwningArena(); }
+    struct Rank1 {};
+    struct Rank0 : Rank1 {};
+
+    static Arena* GetOwningArena(const T* p) {
+      return GetOwningArena(Rank0{}, p);
+    }
+
+    template <typename U>
+    static auto GetOwningArena(Rank0, const U* p)
+        -> decltype(p->GetOwningArena()) {
+      return p->GetOwningArena();
+    }
+
+    template <typename U>
+    static Arena* GetOwningArena(Rank1, const U* p) {
+      return nullptr;
+    }
 
     static void InternalSwap(T* a, T* b) { a->InternalSwap(b); }
 
@@ -771,25 +795,6 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     return nullptr;
   }
 
-  template <typename T>
-  PROTOBUF_ALWAYS_INLINE static Arena* GetOwningArena(const T* value) {
-    return GetOwningArenaInternal(
-        value, std::is_convertible<T*, MessageLite*>());
-  }
-
-  // Implementation for GetOwningArena(). All and only message objects have
-  // GetOwningArena() method.
-  template <typename T>
-  PROTOBUF_ALWAYS_INLINE static Arena* GetOwningArenaInternal(
-      const T* value, std::true_type) {
-    return InternalHelper<T>::GetOwningArena(value);
-  }
-  template <typename T>
-  PROTOBUF_ALWAYS_INLINE static Arena* GetOwningArenaInternal(
-      const T* /* value */, std::false_type) {
-    return nullptr;
-  }
-
   void* AllocateAlignedWithHookForArray(size_t n, size_t align,
                                         const std::type_info* type) {
     if (align <= 8) {

src/google/protobuf/arena_unittest.cc

@@ -307,6 +307,26 @@ TEST(ArenaTest, InitialBlockTooSmall) {
   }
 }
 
+TEST(ArenaTest, CreateDestroy) {
+  TestAllTypes original;
+  TestUtil::SetAllFields(&original);
+
+  // Test memory leak.
+  Arena arena;
+  TestAllTypes* heap_message = Arena::CreateMessage<TestAllTypes>(nullptr);
+  TestAllTypes* arena_message = Arena::CreateMessage<TestAllTypes>(&arena);
+
+  *heap_message = original;
+  *arena_message = original;
+
+  Arena::Destroy(heap_message);
+  Arena::Destroy(arena_message);
+
+  // The arena message should still exist.
+  EXPECT_EQ(strlen(original.optional_string().c_str()),
+            strlen(arena_message->optional_string().c_str()));
+}
+
 TEST(ArenaTest, Parsing) {
   TestAllTypes original;
   TestUtil::SetAllFields(&original);

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

@@ -135,8 +135,6 @@ bool CppGenerator::Generate(const FileDescriptor* file,
               .insert(options[i].second.substr(pos, next_pos - pos));
         pos = next_pos + 1;
       } while (pos < options[i].second.size());
-    } else if (options[i].first == "verified_lazy") {
-      file_options.unverified_lazy = false;
     } else if (options[i].first == "unverified_lazy_message_sets") {
       file_options.unverified_lazy_message_sets = true;
     } else if (options[i].first == "message_owned_arena_trial") {

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

@@ -80,7 +80,6 @@ struct Options {
   bool annotate_accessor = false;
   bool unused_field_stripping = false;
   bool unverified_lazy_message_sets = false;
-  bool unverified_lazy = false;
   bool profile_driven_inline_string = true;
   bool message_owned_arena_trial = false;
   bool force_split = false;

src/google/protobuf/generated_message_reflection_unittest.cc

@@ -1261,8 +1261,6 @@ TEST(GeneratedMessageReflectionTest, UsageErrors) {
   const Reflection* reflection = message.GetReflection();
   const Descriptor* descriptor = message.GetDescriptor();
 
-#define f(NAME) descriptor->FindFieldByName(NAME)
-
   // Testing every single failure mode would be too much work.  Let's just
   // check a few.
   EXPECT_DEATH(
@@ -1301,8 +1299,6 @@ TEST(GeneratedMessageReflectionTest, UsageErrors) {
       "  Message type: protobuf_unittest.TestAllTypes\n"
       "  Field       : protobuf_unittest.ForeignMessage.c\n"
       "  Problem     : Field does not match message type.");
-
-#undef f
 }
 
 #endif  // PROTOBUF_HAS_DEATH_TEST

src/google/protobuf/generated_message_tctable_impl.h

@@ -187,48 +187,48 @@ static_assert(kFmtShift + kFmtBits <= 16, "too many bits");
 // Convenience aliases (16 bits, with format):
 enum FieldType : uint16_t {
   // Numeric types:
-  kBool            = kFkVarint | kRep8Bits,
-
-  kFixed32         = kFkFixed  | kRep32Bits | kFmtUnsigned,
-  kUInt32          = kFkVarint | kRep32Bits | kFmtUnsigned,
-  kSFixed32        = kFkFixed  | kRep32Bits | kFmtSigned,
-  kInt32           = kFkVarint | kRep32Bits | kFmtSigned,
-  kSInt32          = kFkVarint | kRep32Bits | kFmtSigned | kTvZigZag,
-  kFloat           = kFkFixed  | kRep32Bits | kFmtFloating,
-  kEnum            = kFkVarint | kRep32Bits | kFmtEnum   | kTvEnum,
-  kEnumRange       = kFkVarint | kRep32Bits | kFmtEnum   | kTvRange,
-  kOpenEnum        = kFkVarint | kRep32Bits | kFmtEnum,
-
-  kFixed64         = kFkFixed  | kRep64Bits | kFmtUnsigned,
-  kUInt64          = kFkVarint | kRep64Bits | kFmtUnsigned,
-  kSFixed64        = kFkFixed  | kRep64Bits | kFmtSigned,
-  kInt64           = kFkVarint | kRep64Bits | kFmtSigned,
-  kSInt64          = kFkVarint | kRep64Bits | kFmtSigned | kTvZigZag,
-  kDouble          = kFkFixed  | kRep64Bits | kFmtFloating,
-
-  kPackedBool      = kFkPackedVarint | kRep8Bits,
-
-  kPackedFixed32   = kFkPackedFixed  | kRep32Bits | kFmtUnsigned,
-  kPackedUInt32    = kFkPackedVarint | kRep32Bits | kFmtUnsigned,
-  kPackedSFixed32  = kFkPackedFixed  | kRep32Bits | kFmtSigned,
-  kPackedInt32     = kFkPackedVarint | kRep32Bits | kFmtSigned,
-  kPackedSInt32    = kFkPackedVarint | kRep32Bits | kFmtSigned | kTvZigZag,
-  kPackedFloat     = kFkPackedFixed  | kRep32Bits | kFmtFloating,
-  kPackedEnum      = kFkPackedVarint | kRep32Bits | kFmtEnum   | kTvEnum,
-  kPackedEnumRange = kFkPackedVarint | kRep32Bits | kFmtEnum   | kTvRange,
-  kPackedOpenEnum  = kFkPackedVarint | kRep32Bits | kFmtEnum,
-
-  kPackedFixed64   = kFkPackedFixed  | kRep64Bits | kFmtUnsigned,
-  kPackedUInt64    = kFkPackedVarint | kRep64Bits | kFmtUnsigned,
-  kPackedSFixed64  = kFkPackedFixed  | kRep64Bits | kFmtSigned,
-  kPackedInt64     = kFkPackedVarint | kRep64Bits | kFmtSigned,
-  kPackedSInt64    = kFkPackedVarint | kRep64Bits | kFmtSigned | kTvZigZag,
-  kPackedDouble    = kFkPackedFixed  | kRep64Bits | kFmtFloating,
+  kBool            = 0 | kFkVarint | kRep8Bits,
+
+  kFixed32         = 0 | kFkFixed  | kRep32Bits | kFmtUnsigned,
+  kUInt32          = 0 | kFkVarint | kRep32Bits | kFmtUnsigned,
+  kSFixed32        = 0 | kFkFixed  | kRep32Bits | kFmtSigned,
+  kInt32           = 0 | kFkVarint | kRep32Bits | kFmtSigned,
+  kSInt32          = 0 | kFkVarint | kRep32Bits | kFmtSigned | kTvZigZag,
+  kFloat           = 0 | kFkFixed  | kRep32Bits | kFmtFloating,
+  kEnum            = 0 | kFkVarint | kRep32Bits | kFmtEnum   | kTvEnum,
+  kEnumRange       = 0 | kFkVarint | kRep32Bits | kFmtEnum   | kTvRange,
+  kOpenEnum        = 0 | kFkVarint | kRep32Bits | kFmtEnum,
+
+  kFixed64         = 0 | kFkFixed  | kRep64Bits | kFmtUnsigned,
+  kUInt64          = 0 | kFkVarint | kRep64Bits | kFmtUnsigned,
+  kSFixed64        = 0 | kFkFixed  | kRep64Bits | kFmtSigned,
+  kInt64           = 0 | kFkVarint | kRep64Bits | kFmtSigned,
+  kSInt64          = 0 | kFkVarint | kRep64Bits | kFmtSigned | kTvZigZag,
+  kDouble          = 0 | kFkFixed  | kRep64Bits | kFmtFloating,
+
+  kPackedBool      = 0 | kFkPackedVarint | kRep8Bits,
+
+  kPackedFixed32   = 0 | kFkPackedFixed  | kRep32Bits | kFmtUnsigned,
+  kPackedUInt32    = 0 | kFkPackedVarint | kRep32Bits | kFmtUnsigned,
+  kPackedSFixed32  = 0 | kFkPackedFixed  | kRep32Bits | kFmtSigned,
+  kPackedInt32     = 0 | kFkPackedVarint | kRep32Bits | kFmtSigned,
+  kPackedSInt32    = 0 | kFkPackedVarint | kRep32Bits | kFmtSigned | kTvZigZag,
+  kPackedFloat     = 0 | kFkPackedFixed  | kRep32Bits | kFmtFloating,
+  kPackedEnum      = 0 | kFkPackedVarint | kRep32Bits | kFmtEnum   | kTvEnum,
+  kPackedEnumRange = 0 | kFkPackedVarint | kRep32Bits | kFmtEnum   | kTvRange,
+  kPackedOpenEnum  = 0 | kFkPackedVarint | kRep32Bits | kFmtEnum,
+
+  kPackedFixed64   = 0 | kFkPackedFixed  | kRep64Bits | kFmtUnsigned,
+  kPackedUInt64    = 0 | kFkPackedVarint | kRep64Bits | kFmtUnsigned,
+  kPackedSFixed64  = 0 | kFkPackedFixed  | kRep64Bits | kFmtSigned,
+  kPackedInt64     = 0 | kFkPackedVarint | kRep64Bits | kFmtSigned,
+  kPackedSInt64    = 0 | kFkPackedVarint | kRep64Bits | kFmtSigned | kTvZigZag,
+  kPackedDouble    = 0 | kFkPackedFixed  | kRep64Bits | kFmtFloating,
 
   // String types:
-  kBytes           = kFkString | kFmtArray,
-  kRawString       = kFkString | kFmtUtf8  | kTvUtf8Debug,
-  kUtf8String      = kFkString | kFmtUtf8  | kTvUtf8,
+  kBytes           = 0 | kFkString | kFmtArray,
+  kRawString       = 0 | kFkString | kFmtUtf8  | kTvUtf8Debug,
+  kUtf8String      = 0 | kFkString | kFmtUtf8  | kTvUtf8,
 
   // Message types:
   kMessage         = kFkMessage,
@@ -236,7 +236,6 @@ enum FieldType : uint16_t {
   // Map types:
   kMap             = kFkMap,
 };
-
 // clang-format on
 }  // namespace field_layout
 

src/google/protobuf/map.h

@@ -1364,7 +1364,8 @@ class Map {
   template <class InputIt>
   void insert(InputIt first, InputIt last) {
     for (; first != last; ++first) {
-      try_emplace(first->first, first->second);
+      auto&& pair = *first;
+      try_emplace(pair.first, pair.second);
     }
   }
   void insert(std::initializer_list<value_type> values) {

src/google/protobuf/repeated_field.h

@@ -246,7 +246,7 @@ class RepeatedField final {
   Element* mutable_data();
   const Element* data() const;
 
-  // Swaps entire contents with "other". If they are separate arenas then,
+  // Swaps entire contents with "other". If they are separate arenas, then
   // copies data between each other.
   void Swap(RepeatedField* other);
 
@@ -313,8 +313,14 @@ class RepeatedField final {
   iterator erase(const_iterator first, const_iterator last);
 
   // Gets the Arena on which this RepeatedField stores its elements.
+  // Message-owned arenas are not exposed by this method, which will return
+  // nullptr for messages owned by MOAs.
   inline Arena* GetArena() const {
-    return GetOwningArena();
+    Arena* arena = GetOwningArena();
+    if (arena == nullptr || arena->InternalIsMessageOwnedArena()) {
+      return nullptr;
+    }
+    return arena;
   }
 
   // For internal use only.

src/google/protobuf/repeated_ptr_field.h

@@ -612,7 +612,16 @@ class PROTOBUF_EXPORT RepeatedPtrFieldBase {
     temp.Destroy<TypeHandler>();  // Frees rep_ if `other` had no arena.
   }
 
-  inline Arena* GetArena() const { return arena_; }
+  // Gets the Arena on which this RepeatedPtrField stores its elements.
+  // Message-owned arenas are not exposed by this method, which will return
+  // nullptr for messages owned by MOAs.
+  inline Arena* GetArena() const {
+    Arena* arena = GetOwningArena();
+    if (arena == nullptr || arena->InternalIsMessageOwnedArena()) {
+      return nullptr;
+    }
+    return arena;
+  }
 
  protected:
   inline Arena* GetOwningArena() const { return arena_; }
@@ -762,7 +771,7 @@ class GenericTypeHandler {
     }
   }
   static inline Arena* GetOwningArena(GenericType* value) {
-    return Arena::GetOwningArena<Type>(value);
+    return Arena::InternalGetOwningArena(value);
   }
 
   static inline void Clear(GenericType* value) { value->Clear(); }

src/google/protobuf/stubs/common.cc

@@ -178,7 +178,7 @@ void NullLogHandler(LogLevel /* level */, const char* /* filename */,
 }
 
 static LogHandler* log_handler_ = &DefaultLogHandler;
-static std::atomic<int> log_silencer_count_ = ATOMIC_VAR_INIT(0);
+static std::atomic<int> log_silencer_count_{0};
 
 LogMessage& LogMessage::operator<<(const std::string& value) {
   message_ += value;

src/google/protobuf/util/internal/protostream_objectsource.h

@@ -77,9 +77,6 @@ class PROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
  public:
 
   struct RenderOptions {
-    RenderOptions() = default;
-    RenderOptions(const RenderOptions&) = default;
-
     // Sets whether or not to use lowerCamelCase casing for enum values. If set
     // to false, enum values are output without any case conversions.
     //