Add unit-tests for the C++ generator

PiperOrigin-RevId: 542674144

src/google/protobuf/compiler/code_generator.h

@@ -43,6 +43,7 @@
 #include <vector>
 
 #include "absl/strings/string_view.h"
+#include "google/protobuf/descriptor.h"
 #include "google/protobuf/port.h"
 
 // Must be included last.
@@ -124,6 +125,7 @@ class PROTOC_EXPORT CodeGenerator {
   // version of the library. When protobufs does a api breaking change, the
   // method can be removed.
   virtual bool HasGenerateAll() const { return true; }
+
 };
 
 // CodeGenerators generate one or more files in a given directory.  This

src/google/protobuf/compiler/cpp/BUILD.bazel

@@ -184,6 +184,18 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "generator_unittest",
+    srcs = ["generator_unittest.cc"],
+    deps = [
+        ":cpp",
+        "//:protobuf",
+        "//src/google/protobuf/compiler:command_line_interface_tester",
+        "@com_google_googletest//:gtest",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_test(
     name = "message_size_unittest",
     srcs = ["message_size_unittest.cc"],

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

@@ -40,12 +40,15 @@
 #include <utility>
 #include <vector>
 
+#include "absl/status/status.h"
 #include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/cpp/file.h"
 #include "google/protobuf/compiler/cpp/helpers.h"
 #include "google/protobuf/descriptor.pb.h"
+#include "google/protobuf/descriptor_visitor.h"
+
 
 namespace google {
 namespace protobuf {
@@ -96,6 +99,7 @@ absl::flat_hash_map<absl::string_view, std::string> CommonVars(
        "K"},
   };
 }
+
 }  // namespace
 
 bool CppGenerator::Generate(const FileDescriptor* file,
@@ -235,6 +239,12 @@ bool CppGenerator::Generate(const FileDescriptor* file,
     return true;
   }
 
+  absl::Status validation_result = ValidateFeatures(file);
+  if (!validation_result.ok()) {
+    *error = std::string(validation_result.message());
+    return false;
+  }
+
   FileGenerator file_generator(file, file_options);
 
   // Generate header(s).
@@ -351,6 +361,12 @@ bool CppGenerator::Generate(const FileDescriptor* file,
 
   return true;
 }
+
+absl::Status CppGenerator::ValidateFeatures(const FileDescriptor* file) const {
+  absl::Status status = absl::OkStatus();
+  return status;
+}
+
 }  // namespace cpp
 }  // namespace compiler
 }  // namespace protobuf

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

@@ -41,6 +41,7 @@
 #include <utility>
 
 #include "google/protobuf/compiler/code_generator.h"
+#include "absl/status/status.h"
 
 // Must be included last.
 #include "google/protobuf/port_def.inc"
@@ -94,6 +95,8 @@ class PROTOC_EXPORT CppGenerator : public CodeGenerator {
  private:
   bool opensource_runtime_ = PROTO2_IS_OSS;
   std::string runtime_include_base_;
+
+  absl::Status ValidateFeatures(const FileDescriptor* file) const;
 };
 }  // namespace cpp
 }  // namespace compiler

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

@@ -0,0 +1,92 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2023 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.
+
+#include "google/protobuf/compiler/cpp/generator.h"
+
+#include <memory>
+
+#include "google/protobuf/descriptor.pb.h"
+#include <gtest/gtest.h>
+#include "google/protobuf/compiler/command_line_interface_tester.h"
+
+namespace google {
+namespace protobuf {
+namespace compiler {
+namespace cpp {
+namespace {
+
+class CppGeneratorTest : public CommandLineInterfaceTester {
+ protected:
+  CppGeneratorTest() {
+    RegisterGenerator("--cpp_out", "--cpp_opt",
+                      std::make_unique<CppGenerator>(), "C++ test generator");
+
+    // Generate built-in protos.
+    CreateTempFile(
+        "net/proto2/proto/descriptor.proto",
+        google::protobuf::DescriptorProto::descriptor()->file()->DebugString());
+  }
+};
+
+TEST_F(CppGeneratorTest, Basic) {
+  CreateTempFile("foo.proto",
+                 R"schema(
+    syntax = "proto2";
+    message Foo {
+      optional int32 bar = 1;
+    })schema");
+
+  RunProtoc(
+      "protocol_compiler --proto_path=$tmpdir --cpp_out=$tmpdir foo.proto");
+
+  ExpectNoErrors();
+}
+
+TEST_F(CppGeneratorTest, BasicError) {
+  CreateTempFile("foo.proto",
+                 R"schema(
+    syntax = "proto2";
+    message Foo {
+      int32 bar = 1;
+    })schema");
+
+  RunProtoc(
+      "protocol_compiler --proto_path=$tmpdir --cpp_out=$tmpdir foo.proto");
+
+  ExpectErrorSubstring(
+      "foo.proto:4:7: Expected \"required\", \"optional\", or \"repeated\"");
+}
+
+
+}  // namespace
+}  // namespace cpp
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google

src/google/protobuf/descriptor.h

@@ -137,6 +137,7 @@ class UnknownField;
 
 // Defined in command_line_interface.cc
 namespace compiler {
+class CodeGenerator;
 class CommandLineInterface;
 namespace cpp {
 // Defined in helpers.h