Implement feature lifetime validation in protoc and the C++ runtime.

Features need to be validated within the pool being built, since the generated pool only contains extensions linked into the binary (e.g. protoc or a runtime building dynamic protos).  The generated pool may be missing extensions used in this proto or it may have version skew.  Moving to the build pool requires reflective parsing, which in general can't be done from inside the pool's database lock.  This required some refactoring to add a post-build validation phase outside of the lock.

For now, the feature support spec is optional and the checks only are only applied when it's present.  Follow-up changes will add these specs to our existing features and then require them for all FeatureSet extensions.

PiperOrigin-RevId: 623630219

python/google/protobuf/internal/descriptor_test.py

@@ -1450,6 +1450,7 @@ class ReturnObject:
 
     ret = ReturnObject()
     ret.pool = descriptor_pool.DescriptorPool()
+
     defaults = descriptor_pb2.FeatureSetDefaults(
         defaults=[
             descriptor_pb2.FeatureSetDefaults.FeatureSetEditionDefault(
@@ -1465,6 +1466,13 @@ class ReturnObject:
     ].multiple_feature = 1
     ret.pool.SetFeatureSetDefaults(defaults)
 
+    # Add dependencies
+    file = descriptor_pb2.FileDescriptorProto()
+    descriptor_pb2.DESCRIPTOR.CopyToProto(file)
+    ret.pool.Add(file)
+    unittest_features_pb2.DESCRIPTOR.CopyToProto(file)
+    ret.pool.Add(file)
+
     ret.file = ret.pool.AddSerializedFile(self.file_proto.SerializeToString())
     ret.top_message = ret.pool.FindMessageTypeByName(
         'protobuf_unittest.TopMessage'

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -1761,6 +1761,63 @@ TEST_F(CommandLineInterfaceTest, Plugin_SourceFeatures) {
   }
 }
 
+TEST_F(CommandLineInterfaceTest, GeneratorFeatureLifetimeError) {
+  CreateTempFile("google/protobuf/descriptor.proto",
+                 google::protobuf::DescriptorProto::descriptor()->file()->DebugString());
+  CreateTempFile("google/protobuf/unittest_features.proto",
+                 pb::TestFeatures::descriptor()->file()->DebugString());
+  CreateTempFile("foo.proto",
+                 R"schema(
+    edition = "2024";
+    import "google/protobuf/unittest_features.proto";
+    package foo;
+    message Foo {
+      int32 b = 1 [
+        features.(pb.test).removed_feature = VALUE6
+      ];
+    }
+  )schema");
+
+  Run("protocol_compiler --experimental_editions --proto_path=$tmpdir "
+      "--test_out=$tmpdir foo.proto");
+  ExpectErrorSubstring(
+      "foo.proto:6:13: Feature pb.TestFeatures.removed_feature has been "
+      "removed in edition 2024");
+}
+
+TEST_F(CommandLineInterfaceTest, PluginFeatureLifetimeError) {
+  CreateTempFile("google/protobuf/descriptor.proto",
+                 google::protobuf::DescriptorProto::descriptor()->file()->DebugString());
+  CreateTempFile("google/protobuf/unittest_features.proto",
+                 pb::TestFeatures::descriptor()->file()->DebugString());
+  CreateTempFile("foo.proto",
+                 R"schema(
+    edition = "2023";
+    import "google/protobuf/unittest_features.proto";
+    package foo;
+    message Foo {
+      int32 b = 1 [
+        features.(pb.test).future_feature = VALUE6
+      ];
+    }
+  )schema");
+
+#ifdef GOOGLE_PROTOBUF_FAKE_PLUGIN_PATH
+  std::string plugin_path = GOOGLE_PROTOBUF_FAKE_PLUGIN_PATH;
+#else
+  std::string plugin_path = absl::StrCat(
+      TestUtil::TestSourceDir(), "/google/protobuf/compiler/fake_plugin");
+#endif
+
+  Run(absl::StrCat(
+      "protocol_compiler --fake_plugin_out=$tmpdir --proto_path=$tmpdir "
+      "foo.proto --plugin=prefix-gen-fake_plugin=",
+      plugin_path));
+  ExpectErrorSubstring(
+      "foo.proto:6:13: Feature pb.TestFeatures.future_feature wasn't "
+      "introduced until edition 2024");
+}
+
 TEST_F(CommandLineInterfaceTest, GeneratorNoEditionsSupport) {
   CreateTempFile("foo.proto", R"schema(
     edition = "2023";
@@ -1958,26 +2015,26 @@ TEST_F(CommandLineInterfaceTest, EditionDefaultsWithExtension) {
   FeatureSetDefaults defaults = ReadEditionDefaults("defaults");
   EXPECT_EQ(defaults.minimum_edition(), EDITION_PROTO2);
   EXPECT_EQ(defaults.maximum_edition(), EDITION_99999_TEST_ONLY);
-  ASSERT_EQ(defaults.defaults_size(), 5);
+  ASSERT_EQ(defaults.defaults_size(), 6);
   EXPECT_EQ(defaults.defaults(0).edition(), EDITION_PROTO2);
-  EXPECT_EQ(defaults.defaults(1).edition(), EDITION_PROTO3);
   EXPECT_EQ(defaults.defaults(2).edition(), EDITION_2023);
-  EXPECT_EQ(defaults.defaults(3).edition(), EDITION_99997_TEST_ONLY);
-  EXPECT_EQ(defaults.defaults(4).edition(), EDITION_99998_TEST_ONLY);
+  EXPECT_EQ(defaults.defaults(3).edition(), EDITION_2024);
+  EXPECT_EQ(defaults.defaults(4).edition(), EDITION_99997_TEST_ONLY);
+  EXPECT_EQ(defaults.defaults(5).edition(), EDITION_99998_TEST_ONLY);
   EXPECT_EQ(
       defaults.defaults(0).features().GetExtension(pb::test).file_feature(),
       pb::EnumFeature::VALUE1);
-  EXPECT_EQ(
-      defaults.defaults(1).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE2);
   EXPECT_EQ(
       defaults.defaults(2).features().GetExtension(pb::test).file_feature(),
       pb::EnumFeature::VALUE3);
   EXPECT_EQ(
       defaults.defaults(3).features().GetExtension(pb::test).file_feature(),
-      pb::EnumFeature::VALUE4);
+      pb::EnumFeature::VALUE3);
   EXPECT_EQ(
       defaults.defaults(4).features().GetExtension(pb::test).file_feature(),
+      pb::EnumFeature::VALUE4);
+  EXPECT_EQ(
+      defaults.defaults(5).features().GetExtension(pb::test).file_feature(),
       pb::EnumFeature::VALUE5);
 }