add go_features.proto, cpp_features.proto, and java_features.proto to…

… protocompile.WithStandardImports

internal/featuresext/featuresext.go

@@ -0,0 +1,83 @@
+// Copyright 2020-2024 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package featuresext provides file descriptors for the
+// "google/protobuf/cpp_features.proto" and "google/protobuf/java_features.proto"
+// standard import files. Unlike the other standard/well-known
+// imports, these files have no standard Go package in their
+// runtime with generated code. So in order to make them available
+// as "standard imports" to compiler users, we must embed these
+// descriptors into a Go package.
+package featuresext
+
+import (
+	_ "embed"
+	"fmt"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protodesc"
+	"google.golang.org/protobuf/reflect/protoreflect"
+	"google.golang.org/protobuf/reflect/protoregistry"
+	"google.golang.org/protobuf/types/descriptorpb"
+	"sync"
+)
+
+var (
+	//go:embed cpp_features.protoset
+	cppFeatures []byte
+
+	//go:embed java_features.protoset
+	javaFeatures []byte
+
+	initOnce         sync.Once
+	initCppFeatures  protoreflect.FileDescriptor
+	initCppErr       error
+	initJavaFeatures protoreflect.FileDescriptor
+	initJavaErr      error
+)
+
+func initDescriptors() {
+	initOnce.Do(func() {
+		initCppFeatures, initCppErr = buildDescriptor("google/protobuf/cpp_features.proto", cppFeatures)
+		initJavaFeatures, initJavaErr = buildDescriptor("google/protobuf/java_features.proto", javaFeatures)
+	})
+}
+
+func CppFeaturesDescriptor() (protoreflect.FileDescriptor, error) {
+	initDescriptors()
+	return initCppFeatures, initCppErr
+}
+
+func JavaFeaturesDescriptor() (protoreflect.FileDescriptor, error) {
+	initDescriptors()
+	return initJavaFeatures, initJavaErr
+}
+
+func buildDescriptor(name string, data []byte) (protoreflect.FileDescriptor, error) {
+	var files descriptorpb.FileDescriptorSet
+	err := proto.Unmarshal(data, &files)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load descriptor for %q: %w", name, err)
+	}
+	if len(files.File) != 1 {
+		return nil, fmt.Errorf("failed to load descriptor for %q: expected embedded descriptor set to contain exactly one file but it instead has %d", name, len(files.File))
+	}
+	if files.File[0].GetName() != name {
+		return nil, fmt.Errorf("failed to load descriptor for %q: embedded descriptor contains wrong file %q", name, files.File[0].GetName())
+	}
+	descriptor, err := protodesc.NewFile(files.File[0], protoregistry.GlobalFiles)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load descriptor for %q: %w", name, err)
+	}
+	return descriptor, nil
+}

internal/featuresext/featuresext_test.go

@@ -0,0 +1,37 @@
+// Copyright 2020-2024 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package featuresext
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/protobuf/reflect/protoreflect"
+)
+
+func TestFeaturesExt(t *testing.T) {
+	t.Parallel()
+
+	file, err := CppFeaturesDescriptor()
+	require.NoError(t, err)
+	assert.Equal(t, protoreflect.FullName("pb"), file.Package())
+	assert.NotNil(t, file.Extensions().ByName("cpp"))
+
+	file, err = JavaFeaturesDescriptor()
+	require.NoError(t, err)
+	assert.Equal(t, protoreflect.FullName("pb"), file.Package())
+	assert.NotNil(t, file.Extensions().ByName("java"))
+}

std_imports.go

@@ -15,9 +15,11 @@
 package protocompile
 
 import (
+	"github.com/bufbuild/protocompile/internal/featuresext"
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
-	_ "google.golang.org/protobuf/types/known/anypb" // link in packages that include the standard protos included with protoc.
+	_ "google.golang.org/protobuf/types/gofeaturespb" // link in packages that include the standard protos included with protoc.
+	_ "google.golang.org/protobuf/types/known/anypb"
 	_ "google.golang.org/protobuf/types/known/apipb"
 	_ "google.golang.org/protobuf/types/known/durationpb"
 	_ "google.golang.org/protobuf/types/known/emptypb"
@@ -44,6 +46,7 @@ func init() {
 		"google/protobuf/duration.proto",
 		"google/protobuf/empty.proto",
 		"google/protobuf/field_mask.proto",
+		"google/protobuf/go_features.proto",
 		"google/protobuf/source_context.proto",
 		"google/protobuf/struct.proto",
 		"google/protobuf/timestamp.proto",
@@ -59,4 +62,33 @@ func init() {
 		}
 		standardImports[fn] = fd
 	}
+
+	otherFeatures := []struct {
+		Name          string
+		GetDescriptor func() (protoreflect.FileDescriptor, error)
+	}{
+		{
+			Name:          "google/protobuf/cpp_features.proto",
+			GetDescriptor: featuresext.CppFeaturesDescriptor,
+		},
+		{
+			Name:          "google/protobuf/java_features.proto",
+			GetDescriptor: featuresext.JavaFeaturesDescriptor,
+		},
+	}
+	for _, feature := range otherFeatures {
+		// First see if the program has gneerated Go code for this
+		// file linked in:
+		fd, err := protoregistry.GlobalFiles.FindFileByPath(feature.Name)
+		if err == nil {
+			standardImports[feature.Name] = fd
+			continue
+		}
+		fd, err = feature.GetDescriptor()
+		if err == nil {
+			continue
+		}
+		// For these extensions to FeatureSet, we are lenient. If
+		// we can't load them, just ignore them.
+	}
 }