snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

encoding/compressor_test.go

@@ -0,0 +1,281 @@
+/*
+ *
+ * Copyright 2025 gRPC authors.
+ *
+ * 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 encoding_test
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"sync/atomic"
+	"testing"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/internal"
+	"google.golang.org/grpc/internal/stubserver"
+	"google.golang.org/grpc/status"
+
+	testgrpc "google.golang.org/grpc/interop/grpc_testing"
+	testpb "google.golang.org/grpc/interop/grpc_testing"
+
+	_ "google.golang.org/grpc/encoding/gzip"
+)
+
+// wrapCompressor is a wrapper of encoding.Compressor which maintains count of
+// Compressor method invokes.
+type wrapCompressor struct {
+	encoding.Compressor
+	compressInvokes int32
+}
+
+func (wc *wrapCompressor) Compress(w io.Writer) (io.WriteCloser, error) {
+	atomic.AddInt32(&wc.compressInvokes, 1)
+	return wc.Compressor.Compress(w)
+}
+
+func setupGzipWrapCompressor(t *testing.T) *wrapCompressor {
+	regFn := internal.RegisterCompressorForTesting.(func(encoding.Compressor) func())
+	c := &wrapCompressor{Compressor: encoding.GetCompressor("gzip")}
+	unreg := regFn(c)
+	t.Cleanup(unreg)
+	return c
+}
+
+func (s) TestSetSendCompressorSuccess(t *testing.T) {
+	for _, tt := range []struct {
+		name                string
+		desc                string
+		payload             *testpb.Payload
+		dialOpts            []grpc.DialOption
+		resCompressor       string
+		wantCompressInvokes int32
+	}{
+		{
+			name:                "identity_request_and_gzip_response",
+			desc:                "request is uncompressed and response is gzip compressed",
+			payload:             &testpb.Payload{Body: []byte("payload")},
+			resCompressor:       "gzip",
+			wantCompressInvokes: 1,
+		},
+		{
+			name:                "identity_request_and_empty_response",
+			desc:                "request is uncompressed and response is gzip compressed",
+			payload:             nil,
+			resCompressor:       "gzip",
+			wantCompressInvokes: 0,
+		},
+		{
+			name:          "gzip_request_and_identity_response",
+			desc:          "request is gzip compressed and response is uncompressed with identity",
+			payload:       &testpb.Payload{Body: []byte("payload")},
+			resCompressor: "identity",
+			dialOpts: []grpc.DialOption{
+				// Use WithCompressor instead of UseCompressor to avoid counting
+				// the client's compressor usage.
+				grpc.WithCompressor(grpc.NewGZIPCompressor()),
+			},
+			wantCompressInvokes: 0,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Run("unary", func(t *testing.T) {
+				testUnarySetSendCompressorSuccess(t, tt.payload, tt.resCompressor, tt.wantCompressInvokes, tt.dialOpts)
+			})
+
+			t.Run("stream", func(t *testing.T) {
+				testStreamSetSendCompressorSuccess(t, tt.payload, tt.resCompressor, tt.wantCompressInvokes, tt.dialOpts)
+			})
+		})
+	}
+}
+
+func testUnarySetSendCompressorSuccess(t *testing.T, payload *testpb.Payload, resCompressor string, wantCompressInvokes int32, dialOpts []grpc.DialOption) {
+	wc := setupGzipWrapCompressor(t)
+	ss := &stubserver.StubServer{
+		UnaryCallF: func(ctx context.Context, _ *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			if err := grpc.SetSendCompressor(ctx, resCompressor); err != nil {
+				return nil, err
+			}
+			return &testpb.SimpleResponse{
+				Payload: payload,
+			}, nil
+		},
+	}
+	if err := ss.Start(nil, dialOpts...); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	if _, err := ss.Client.UnaryCall(ctx, &testpb.SimpleRequest{}); err != nil {
+		t.Fatalf("Unexpected unary call error, got: %v, want: nil", err)
+	}
+
+	compressInvokes := atomic.LoadInt32(&wc.compressInvokes)
+	if compressInvokes != wantCompressInvokes {
+		t.Fatalf("Unexpected compress invokes, got:%d, want: %d", compressInvokes, wantCompressInvokes)
+	}
+}
+
+func testStreamSetSendCompressorSuccess(t *testing.T, payload *testpb.Payload, resCompressor string, wantCompressInvokes int32, dialOpts []grpc.DialOption) {
+	wc := setupGzipWrapCompressor(t)
+	ss := &stubserver.StubServer{
+		FullDuplexCallF: func(stream testgrpc.TestService_FullDuplexCallServer) error {
+			if _, err := stream.Recv(); err != nil {
+				return err
+			}
+
+			if err := grpc.SetSendCompressor(stream.Context(), resCompressor); err != nil {
+				return err
+			}
+
+			return stream.Send(&testpb.StreamingOutputCallResponse{
+				Payload: payload,
+			})
+		},
+	}
+	if err := ss.Start(nil, dialOpts...); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	s, err := ss.Client.FullDuplexCall(ctx)
+	if err != nil {
+		t.Fatalf("Unexpected full duplex call error, got: %v, want: nil", err)
+	}
+
+	if err := s.Send(&testpb.StreamingOutputCallRequest{}); err != nil {
+		t.Fatalf("Unexpected full duplex call send error, got: %v, want: nil", err)
+	}
+
+	if _, err := s.Recv(); err != nil {
+		t.Fatalf("Unexpected full duplex recv error, got: %v, want: nil", err)
+	}
+
+	compressInvokes := atomic.LoadInt32(&wc.compressInvokes)
+	if compressInvokes != wantCompressInvokes {
+		t.Fatalf("Unexpected compress invokes, got:%d, want: %d", compressInvokes, wantCompressInvokes)
+	}
+}
+
+// fakeCompressor returns a messages of a configured size, irrespective of the
+// input.
+type fakeCompressor struct {
+	decompressedMessageSize int
+}
+
+func (f *fakeCompressor) Compress(w io.Writer) (io.WriteCloser, error) {
+	return nopWriteCloser{w}, nil
+}
+
+func (f *fakeCompressor) Decompress(io.Reader) (io.Reader, error) {
+	return bytes.NewReader(make([]byte, f.decompressedMessageSize)), nil
+}
+
+func (f *fakeCompressor) Name() string {
+	// Use the name of an existing compressor to avoid interactions with other
+	// tests since compressors can't be un-registered.
+	return "fake"
+}
+
+type nopWriteCloser struct {
+	io.Writer
+}
+
+func (nopWriteCloser) Close() error {
+	return nil
+}
+
+// TestDecompressionExceedsMaxMessageSize uses a fake compressor that produces
+// messages of size 100 bytes on decompression. A server is started with the
+// max receive message size restricted to 99 bytes. The test verifies that the
+// client receives a ResourceExhausted response from the server.
+func (s) TestDecompressionExceedsMaxMessageSize(t *testing.T) {
+	const messageLen = 100
+	regFn := internal.RegisterCompressorForTesting.(func(encoding.Compressor) func())
+	compressor := &fakeCompressor{decompressedMessageSize: messageLen}
+	unreg := regFn(compressor)
+	defer unreg()
+	ss := &stubserver.StubServer{
+		UnaryCallF: func(context.Context, *testpb.SimpleRequest) (*testpb.SimpleResponse, error) {
+			return &testpb.SimpleResponse{}, nil
+		},
+	}
+	if err := ss.Start([]grpc.ServerOption{grpc.MaxRecvMsgSize(messageLen - 1)}); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	req := &testpb.SimpleRequest{Payload: &testpb.Payload{}}
+	_, err := ss.Client.UnaryCall(ctx, req, grpc.UseCompressor(compressor.Name()))
+	if got, want := status.Code(err), codes.ResourceExhausted; got != want {
+		t.Errorf("Client.UnaryCall(%+v) returned status %v, want %v", req, got, want)
+	}
+}
+
+// Test verifies that decompression failures (after stream establishment) are
+// handled gracefully without duplicate status writes.
+func (s) TestStreamingDecompressionExceedsMaxMessageSize(t *testing.T) {
+	const messageLen = 100
+	regFn := internal.RegisterCompressorForTesting.(func(encoding.Compressor) func())
+	compressor := &fakeCompressor{decompressedMessageSize: messageLen}
+	unreg := regFn(compressor)
+	defer unreg()
+
+	ss := &stubserver.StubServer{
+		FullDuplexCallF: func(stream testgrpc.TestService_FullDuplexCallServer) error {
+			for {
+				if _, err := stream.Recv(); err != nil {
+					return err
+				}
+			}
+		},
+	}
+	if err := ss.Start([]grpc.ServerOption{grpc.MaxRecvMsgSize(messageLen - 1)}); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	stream, err := ss.Client.FullDuplexCall(ctx, grpc.UseCompressor(compressor.Name()))
+	if err != nil {
+		t.Fatalf("FullDuplexCall failed: %v", err)
+	}
+
+	// Send message that will result in decompression failure on the server
+	// because it exceeds the max message size.
+	if err := stream.Send(&testpb.StreamingOutputCallRequest{Payload: &testpb.Payload{Body: []byte("payload")}}); err != nil {
+		t.Fatalf("Send() failed: %v", err)
+	}
+
+	// We expect the stream to fail with ResourceExhausted on Recv.
+	if _, err = stream.Recv(); status.Code(err) != codes.ResourceExhausted {
+		t.Fatalf("stream.Recv() returned status %v, want %v", status.Code(err), codes.ResourceExhausted)
+	}
+}

encoding/encoding.go

@@ -0,0 +1,150 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * 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 encoding defines the interface for the compressor and codec, and
+// functions to register and retrieve compressors and codecs.
+//
+// # Experimental
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a
+// later release.
+package encoding
+
+import (
+	"io"
+	"slices"
+	"strings"
+
+	"google.golang.org/grpc/encoding/internal"
+	"google.golang.org/grpc/internal/grpcutil"
+)
+
+// Identity specifies the optional encoding for uncompressed streams.
+// It is intended for grpc internal use only.
+const Identity = "identity"
+
+func init() {
+	internal.RegisterCompressorForTesting = func(c Compressor) func() {
+		name := c.Name()
+		curCompressor, found := registeredCompressor[name]
+		RegisterCompressor(c)
+		return func() {
+			if found {
+				registeredCompressor[name] = curCompressor
+				return
+			}
+			delete(registeredCompressor, name)
+			grpcutil.RegisteredCompressorNames = slices.DeleteFunc(grpcutil.RegisteredCompressorNames, func(s string) bool {
+				return s == name
+			})
+		}
+	}
+}
+
+// Compressor is used for compressing and decompressing when sending or
+// receiving messages.
+type Compressor interface {
+	// Compress writes the data written to wc to w after compressing it.  If an
+	// error occurs while initializing the compressor, that error is returned
+	// instead.
+	Compress(w io.Writer) (io.WriteCloser, error)
+	// Decompress reads data from r, decompresses it, and provides the
+	// uncompressed data via the returned io.Reader.  If an error occurs while
+	// initializing the decompressor, that error is returned instead.
+	//
+	// The returned io.Reader may optionally implement io.ReadCloser, and if it
+	// does, gRPC will call Close() exactly once.
+	Decompress(r io.Reader) (io.Reader, error)
+	// Name is the name of the compression codec and is used to set the content
+	// coding header.  The result must be static; the result cannot change
+	// between calls.
+	Name() string
+}
+
+var registeredCompressor = make(map[string]Compressor)
+
+// RegisterCompressor registers the compressor with gRPC by its name.  It can
+// be activated when sending an RPC via grpc.UseCompressor().  It will be
+// automatically accessed when receiving a message based on the content coding
+// header.  Servers also use it to send a response with the same encoding as
+// the request.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCompressor(c Compressor) {
+	registeredCompressor[c.Name()] = c
+	if !grpcutil.IsCompressorNameRegistered(c.Name()) {
+		grpcutil.RegisteredCompressorNames = append(grpcutil.RegisteredCompressorNames, c.Name())
+	}
+}
+
+// GetCompressor returns Compressor for the given compressor name.
+func GetCompressor(name string) Compressor {
+	return registeredCompressor[name]
+}
+
+// Codec defines the interface gRPC uses to encode and decode messages.  Note
+// that implementations of this interface must be thread safe; a Codec's
+// methods can be called from concurrent goroutines.
+type Codec interface {
+	// Marshal returns the wire format of v.
+	Marshal(v any) ([]byte, error)
+	// Unmarshal parses the wire format into v.
+	Unmarshal(data []byte, v any) error
+	// Name returns the name of the Codec implementation. The returned string
+	// will be used as part of content type in transmission.  The result must be
+	// static; the result cannot change between calls.
+	Name() string
+}
+
+var registeredCodecs = make(map[string]any)
+
+// RegisterCodec registers the provided Codec for use with all gRPC clients and
+// servers.
+//
+// The Codec will be stored and looked up by result of its Name() method, which
+// should match the content-subtype of the encoding handled by the Codec.  This
+// is case-insensitive, and is stored and looked up as lowercase.  If the
+// result of calling Name() is an empty string, RegisterCodec will panic. See
+// Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Codecs are
+// registered with the same name, the one registered last will take effect.
+func RegisterCodec(codec Codec) {
+	if codec == nil {
+		panic("cannot register a nil Codec")
+	}
+	if codec.Name() == "" {
+		panic("cannot register Codec with empty string result for Name()")
+	}
+	contentSubtype := strings.ToLower(codec.Name())
+	registeredCodecs[contentSubtype] = codec
+}
+
+// GetCodec gets a registered Codec by content-subtype, or nil if no Codec is
+// registered for the content-subtype.
+//
+// The content-subtype is expected to be lowercase.
+func GetCodec(contentSubtype string) Codec {
+	c, _ := registeredCodecs[contentSubtype].(Codec)
+	return c
+}

encoding/encoding_test.go

@@ -0,0 +1,400 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * 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 encoding_test
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/google/go-cmp/cmp"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/encoding/proto"
+	"google.golang.org/grpc/internal/grpctest"
+	"google.golang.org/grpc/internal/grpcutil"
+	"google.golang.org/grpc/internal/stubserver"
+	"google.golang.org/grpc/mem"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+
+	testgrpc "google.golang.org/grpc/interop/grpc_testing"
+	testpb "google.golang.org/grpc/interop/grpc_testing"
+)
+
+const defaultTestTimeout = 10 * time.Second
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+type mockNamedCompressor struct {
+	encoding.Compressor
+}
+
+func (mockNamedCompressor) Name() string {
+	return "mock-compressor"
+}
+
+// Tests the case where a compressor with the same name is registered multiple
+// times. Test verifies the following:
+//   - the most recent registration is the one which is active
+//   - grpcutil.RegisteredCompressorNames contains a single instance of the
+//     previously registered compressor's name
+func (s) TestDuplicateCompressorRegister(t *testing.T) {
+	encoding.RegisterCompressor(&mockNamedCompressor{})
+
+	// Register another instance of the same compressor.
+	mc := &mockNamedCompressor{}
+	encoding.RegisterCompressor(mc)
+	if got := encoding.GetCompressor("mock-compressor"); got != mc {
+		t.Fatalf("Unexpected compressor, got: %+v, want:%+v", got, mc)
+	}
+
+	wantNames := []string{"gzip", "mock-compressor"}
+	if !cmp.Equal(wantNames, grpcutil.RegisteredCompressorNames) {
+		t.Fatalf("Unexpected compressor names, got: %+v, want:%+v", grpcutil.RegisteredCompressorNames, wantNames)
+	}
+}
+
+// errProtoCodec wraps the proto codec and delegates to it if it is configured
+// to return a nil error. Else, it returns the configured error.
+type errProtoCodec struct {
+	name        string
+	encodingErr error
+	decodingErr error
+}
+
+func (c *errProtoCodec) Marshal(v any) (mem.BufferSlice, error) {
+	if c.encodingErr != nil {
+		return nil, c.encodingErr
+	}
+	return encoding.GetCodecV2(proto.Name).Marshal(v)
+}
+
+func (c *errProtoCodec) Unmarshal(data mem.BufferSlice, v any) error {
+	if c.decodingErr != nil {
+		return c.decodingErr
+	}
+	return encoding.GetCodecV2(proto.Name).Unmarshal(data, v)
+}
+
+func (c *errProtoCodec) Name() string {
+	return c.name
+}
+
+// Tests the case where encoding fails on the server. Verifies that there is
+// no panic and that the encoding error is propagated to the client.
+func (s) TestEncodeDoesntPanicOnServer(t *testing.T) {
+	// Create a codec that errors when encoding messages.
+	encodingErr := errors.New("encoding failed")
+	ec := &errProtoCodec{name: t.Name(), encodingErr: encodingErr}
+
+	// Start a server with the above codec.
+	backend1 := stubserver.StubServer{
+		EmptyCallF: func(context.Context, *testpb.Empty) (*testpb.Empty, error) { return &testpb.Empty{}, nil },
+	}
+	if err := backend1.Start([]grpc.ServerOption{grpc.ForceServerCodecV2(ec)}, grpc.WithTransportCredentials(insecure.NewCredentials())); err != nil {
+		t.Fatal(err)
+	}
+	defer backend1.Stop()
+
+	// Make an RPC and expect it to fail. Since we do not specify any codec
+	// here, the proto codec will get automatically used.
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	_, err := backend1.Client.EmptyCall(ctx, &testpb.Empty{})
+	if err == nil || !strings.Contains(err.Error(), encodingErr.Error()) {
+		t.Fatalf("RPC failed with error: %v, want: %v", err, encodingErr)
+	}
+
+	// Configure the codec on the server to not return errors anymore and expect
+	// the RPC to succeed.
+	ec = &errProtoCodec{name: t.Name()}
+	backend2 := stubserver.StubServer{
+		EmptyCallF: func(context.Context, *testpb.Empty) (*testpb.Empty, error) { return &testpb.Empty{}, nil },
+	}
+	if err := backend2.Start([]grpc.ServerOption{grpc.ForceServerCodecV2(ec)}, grpc.WithTransportCredentials(insecure.NewCredentials())); err != nil {
+		t.Fatal(err)
+	}
+	defer backend2.Stop()
+
+	if _, err := backend2.Client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
+		t.Fatalf("RPC failed with error: %v", err)
+	}
+}
+
+// Tests the case where decoding fails on the server. Verifies that there is
+// no panic and that the decoding error is propagated to the client.
+func (s) TestDecodeDoesntPanicOnServer(t *testing.T) {
+	// Create a codec that errors when decoding messages.
+	decodingErr := errors.New("decoding failed")
+	ec := &errProtoCodec{name: t.Name(), decodingErr: decodingErr}
+
+	// Start a server with the above codec and a channel to the server.
+	backend1 := stubserver.StubServer{
+		EmptyCallF: func(context.Context, *testpb.Empty) (*testpb.Empty, error) { return &testpb.Empty{}, nil },
+	}
+	if err := backend1.Start([]grpc.ServerOption{grpc.ForceServerCodecV2(ec)}, grpc.WithTransportCredentials(insecure.NewCredentials())); err != nil {
+		t.Fatal(err)
+	}
+	defer backend1.Stop()
+
+	// Make an RPC and expect it to fail. Since we do not specify any codec
+	// here, the proto codec will get automatically used.
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	_, err := backend1.Client.EmptyCall(ctx, &testpb.Empty{})
+	if err == nil || !strings.Contains(err.Error(), decodingErr.Error()) || !strings.Contains(err.Error(), "grpc: failed to unmarshal the received message") {
+		t.Fatalf("RPC failed with error: %v, want: %v", err, decodingErr)
+	}
+
+	// Configure the codec on the server to not return errors anymore and expect
+	// the RPC to succeed.
+	ec = &errProtoCodec{name: t.Name()}
+	backend2 := stubserver.StubServer{
+		EmptyCallF: func(context.Context, *testpb.Empty) (*testpb.Empty, error) { return &testpb.Empty{}, nil },
+	}
+	if err := backend2.Start([]grpc.ServerOption{grpc.ForceServerCodecV2(ec)}, grpc.WithTransportCredentials(insecure.NewCredentials())); err != nil {
+		t.Fatal(err)
+	}
+	defer backend2.Stop()
+
+	if _, err := backend2.Client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
+		t.Fatalf("RPC failed with error: %v", err)
+	}
+}
+
+// Tests the case where encoding fails on the client . Verifies that there is
+// no panic and that the encoding error is propagated to the RPC caller.
+func (s) TestEncodeDoesntPanicOnClient(t *testing.T) {
+	// Start a server and since we do not specify any codec here, the proto
+	// codec will get automatically used.
+	backend := stubserver.StartTestService(t, nil)
+	defer backend.Stop()
+
+	// Create a codec that errors when encoding messages.
+	encodingErr := errors.New("encoding failed")
+	ec := &errProtoCodec{name: t.Name(), encodingErr: encodingErr}
+
+	// Create a channel to the above server.
+	cc, err := grpc.NewClient(backend.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("Failed to dial test backend at %q: %v", backend.Address, err)
+	}
+	defer cc.Close()
+
+	// Make an RPC with the erroring codec and expect it to fail.
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	client := testgrpc.NewTestServiceClient(cc)
+	_, err = client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(ec))
+	if err == nil || !strings.Contains(err.Error(), encodingErr.Error()) {
+		t.Fatalf("RPC failed with error: %v, want: %v", err, encodingErr)
+	}
+
+	// Configure the codec on the client to not return errors anymore and expect
+	// the RPC to succeed.
+	ec.encodingErr = nil
+	if _, err := client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(ec)); err != nil {
+		t.Fatalf("RPC failed with error: %v", err)
+	}
+}
+
+// Tests the case where decoding fails on the server. Verifies that there is
+// no panic and that the decoding error is propagated to the RPC caller.
+func (s) TestDecodeDoesntPanicOnClient(t *testing.T) {
+	// Start a server and since we do not specify any codec here, the proto
+	// codec will get automatically used.
+	backend := stubserver.StartTestService(t, nil)
+	defer backend.Stop()
+
+	// Create a codec that errors when decoding messages.
+	decodingErr := errors.New("decoding failed")
+	ec := &errProtoCodec{name: t.Name(), decodingErr: decodingErr}
+
+	// Create a channel to the above server.
+	cc, err := grpc.NewClient(backend.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("Failed to dial test backend at %q: %v", backend.Address, err)
+	}
+	defer cc.Close()
+
+	// Make an RPC with the erroring codec and expect it to fail.
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	client := testgrpc.NewTestServiceClient(cc)
+	_, err = client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(ec))
+	if err == nil || !strings.Contains(err.Error(), decodingErr.Error()) {
+		t.Fatalf("RPC failed with error: %v, want: %v", err, decodingErr)
+	}
+
+	// Configure the codec on the client to not return errors anymore and expect
+	// the RPC to succeed.
+	ec.decodingErr = nil
+	if _, err := client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(ec)); err != nil {
+		t.Fatalf("RPC failed with error: %v", err)
+	}
+}
+
+// countingProtoCodec wraps the proto codec and counts the number of times
+// Marshal and Unmarshal are called.
+type countingProtoCodec struct {
+	name string
+
+	// The following fields are accessed atomically.
+	marshalCount   int32
+	unmarshalCount int32
+}
+
+func (p *countingProtoCodec) Marshal(v any) (mem.BufferSlice, error) {
+	atomic.AddInt32(&p.marshalCount, 1)
+	return encoding.GetCodecV2(proto.Name).Marshal(v)
+}
+
+func (p *countingProtoCodec) Unmarshal(data mem.BufferSlice, v any) error {
+	atomic.AddInt32(&p.unmarshalCount, 1)
+	return encoding.GetCodecV2(proto.Name).Unmarshal(data, v)
+}
+
+func (p *countingProtoCodec) Name() string {
+	return p.name
+}
+
+// Tests the case where ForceServerCodec option is used on the server. Verifies
+// that encoding and decoding happen once per RPC.
+func (s) TestForceServerCodec(t *testing.T) {
+	// Create a server with the counting proto codec.
+	codec := &countingProtoCodec{name: t.Name()}
+	backend := stubserver.StartTestService(t, nil, grpc.ForceServerCodecV2(codec))
+	defer backend.Stop()
+
+	// Create a channel to the above server.
+	cc, err := grpc.NewClient(backend.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("Failed to dial test backend at %q: %v", backend.Address, err)
+	}
+	defer cc.Close()
+
+	// Make an RPC and expect it to fail. Since we do not specify any codec
+	// here, the proto codec will get automatically used.
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	client := testgrpc.NewTestServiceClient(cc)
+	if _, err := client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
+		t.Fatalf("ss.Client.EmptyCall(_, _) = _, %v; want _, nil", err)
+	}
+
+	unmarshalCount := atomic.LoadInt32(&codec.unmarshalCount)
+	const wantUnmarshalCount = 1
+	if unmarshalCount != wantUnmarshalCount {
+		t.Fatalf("Unmarshal Count = %d; want %d", unmarshalCount, wantUnmarshalCount)
+	}
+	marshalCount := atomic.LoadInt32(&codec.marshalCount)
+	const wantMarshalCount = 1
+	if marshalCount != wantMarshalCount {
+		t.Fatalf("MarshalCount = %d; want %d", marshalCount, wantMarshalCount)
+	}
+}
+
+// renameProtoCodec wraps the proto codec and allows customizing the Name().
+type renameProtoCodec struct {
+	encoding.CodecV2
+	name string
+}
+
+func (r *renameProtoCodec) Name() string { return r.name }
+
+// TestForceCodecName confirms that the ForceCodec call option sets the subtype
+// in the content-type header according to the Name() of the codec provided.
+// Verifies that the name is converted to lowercase before transmitting.
+func (s) TestForceCodecName(t *testing.T) {
+	wantContentTypeCh := make(chan []string, 1)
+	defer close(wantContentTypeCh)
+
+	// Create a test service backend that pushes the received content-type on a
+	// channel for the test to inspect.
+	ss := &stubserver.StubServer{
+		EmptyCallF: func(ctx context.Context, _ *testpb.Empty) (*testpb.Empty, error) {
+			md, ok := metadata.FromIncomingContext(ctx)
+			if !ok {
+				return nil, status.Errorf(codes.Internal, "no metadata in context")
+			}
+			if got, want := md["content-type"], <-wantContentTypeCh; !cmp.Equal(got, want) {
+				return nil, status.Errorf(codes.Internal, "got content-type=%q; want [%q]", got, want)
+			}
+			return &testpb.Empty{}, nil
+		},
+	}
+	// Since we don't specify a codec as a server option, it will end up
+	// automatically using the proto codec.
+	if err := ss.Start(nil); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	// Force the use of the custom codec on the client with the ForceCodec call
+	// option. Confirm the name is converted to lowercase before transmitting.
+	codec := &renameProtoCodec{CodecV2: encoding.GetCodecV2(proto.Name), name: t.Name()}
+	wantContentTypeCh <- []string{fmt.Sprintf("application/grpc+%s", strings.ToLower(t.Name()))}
+	if _, err := ss.Client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(codec)); err != nil {
+		t.Fatalf("ss.Client.EmptyCall(_, _) = _, %v; want _, nil", err)
+	}
+}
+
+// Tests the case where the client uses a codec (one that uses proto encoding
+// but uses a different content-subtype name) that the server does not support.
+// Verifies that the server falls back to the proto codec and that the client
+// can successfully make RPCs.
+//
+// TODO(https://github.com/grpc/grpc-go/issues/1824): Once we add an environment
+// variable to change the behavior on the server to reject unsupported codecs,
+// we should modify this test to verify that the RPC fails in that case.
+func (s) TestUnsupportedCodecOnServer(t *testing.T) {
+	backend := stubserver.StartTestService(t, nil)
+	defer backend.Stop()
+
+	cc, err := grpc.NewClient(backend.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	if err != nil {
+		t.Fatalf("Failed to dial test backend at %q: %v", backend.Address, err)
+	}
+	defer cc.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	codec := &renameProtoCodec{CodecV2: encoding.GetCodecV2(proto.Name), name: t.Name()}
+	client := testgrpc.NewTestServiceClient(cc)
+	if _, err := client.EmptyCall(ctx, &testpb.Empty{}, grpc.ForceCodecV2(codec)); err != nil {
+		t.Fatalf("ss.Client.EmptyCall(_, _) = _, %v; want _, nil", err)
+	}
+}

encoding/encoding_v2.go

@@ -0,0 +1,81 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * 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 encoding
+
+import (
+	"strings"
+
+	"google.golang.org/grpc/mem"
+)
+
+// CodecV2 defines the interface gRPC uses to encode and decode messages. Note
+// that implementations of this interface must be thread safe; a CodecV2's
+// methods can be called from concurrent goroutines.
+type CodecV2 interface {
+	// Marshal returns the wire format of v. The buffers in the returned
+	// [mem.BufferSlice] must have at least one reference each, which will be freed
+	// by gRPC when they are no longer needed.
+	Marshal(v any) (out mem.BufferSlice, err error)
+	// Unmarshal parses the wire format into v. Note that data will be freed as soon
+	// as this function returns. If the codec wishes to guarantee access to the data
+	// after this function, it must take its own reference that it frees when it is
+	// no longer needed.
+	Unmarshal(data mem.BufferSlice, v any) error
+	// Name returns the name of the Codec implementation. The returned string
+	// will be used as part of content type in transmission.  The result must be
+	// static; the result cannot change between calls.
+	Name() string
+}
+
+// RegisterCodecV2 registers the provided CodecV2 for use with all gRPC clients and
+// servers.
+//
+// The CodecV2 will be stored and looked up by result of its Name() method, which
+// should match the content-subtype of the encoding handled by the CodecV2.  This
+// is case-insensitive, and is stored and looked up as lowercase.  If the
+// result of calling Name() is an empty string, RegisterCodecV2 will panic. See
+// Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// If both a Codec and CodecV2 are registered with the same name, the CodecV2
+// will be used.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Codecs are
+// registered with the same name, the one registered last will take effect.
+func RegisterCodecV2(codec CodecV2) {
+	if codec == nil {
+		panic("cannot register a nil CodecV2")
+	}
+	if codec.Name() == "" {
+		panic("cannot register CodecV2 with empty string result for Name()")
+	}
+	contentSubtype := strings.ToLower(codec.Name())
+	registeredCodecs[contentSubtype] = codec
+}
+
+// GetCodecV2 gets a registered CodecV2 by content-subtype, or nil if no CodecV2 is
+// registered for the content-subtype.
+//
+// The content-subtype is expected to be lowercase.
+func GetCodecV2(contentSubtype string) CodecV2 {
+	c, _ := registeredCodecs[contentSubtype].(CodecV2)
+	return c
+}

encoding/gzip/gzip.go

@@ -0,0 +1,124 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * 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 gzip implements and registers the gzip compressor
+// during the initialization.
+//
+// # Experimental
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a
+// later release.
+package gzip
+
+import (
+	"compress/gzip"
+	"fmt"
+	"io"
+	"sync"
+
+	"google.golang.org/grpc/encoding"
+)
+
+// Name is the name registered for the gzip compressor.
+const Name = "gzip"
+
+func init() {
+	c := &compressor{}
+	c.poolCompressor.New = func() any {
+		return &writer{Writer: gzip.NewWriter(io.Discard), pool: &c.poolCompressor}
+	}
+	encoding.RegisterCompressor(c)
+}
+
+type writer struct {
+	*gzip.Writer
+	pool *sync.Pool
+}
+
+// SetLevel updates the registered gzip compressor to use the compression level specified (gzip.HuffmanOnly is not supported).
+// NOTE: this function must only be called during initialization time (i.e. in an init() function),
+// and is not thread-safe.
+//
+// The error returned will be nil if the specified level is valid.
+func SetLevel(level int) error {
+	if level < gzip.DefaultCompression || level > gzip.BestCompression {
+		return fmt.Errorf("grpc: invalid gzip compression level: %d", level)
+	}
+	c := encoding.GetCompressor(Name).(*compressor)
+	c.poolCompressor.New = func() any {
+		w, err := gzip.NewWriterLevel(io.Discard, level)
+		if err != nil {
+			panic(err)
+		}
+		return &writer{Writer: w, pool: &c.poolCompressor}
+	}
+	return nil
+}
+
+func (c *compressor) Compress(w io.Writer) (io.WriteCloser, error) {
+	z := c.poolCompressor.Get().(*writer)
+	z.Writer.Reset(w)
+	return z, nil
+}
+
+func (z *writer) Close() error {
+	defer z.pool.Put(z)
+	return z.Writer.Close()
+}
+
+var _ io.Closer = &reader{}
+
+type reader struct {
+	*gzip.Reader
+	pool *sync.Pool
+}
+
+func (c *compressor) Decompress(r io.Reader) (io.Reader, error) {
+	z, inPool := c.poolDecompressor.Get().(*reader)
+	if !inPool {
+		newZ, err := gzip.NewReader(r)
+		if err != nil {
+			return nil, err
+		}
+		return &reader{Reader: newZ, pool: &c.poolDecompressor}, nil
+	}
+	if err := z.Reset(r); err != nil {
+		c.poolDecompressor.Put(z)
+		return nil, err
+	}
+	return z, nil
+}
+
+func (r *reader) Read(p []byte) (n int, err error) {
+	n, err = r.Reader.Read(p)
+	return n, err
+}
+
+func (r *reader) Close() error {
+	defer r.pool.Put(r)
+	return r.Reader.Close()
+}
+
+func (c *compressor) Name() string {
+	return Name
+}
+
+type compressor struct {
+	poolCompressor   sync.Pool
+	poolDecompressor sync.Pool
+}

encoding/internal/internal.go

@@ -0,0 +1,28 @@
+/*
+ *
+ * Copyright 2025 gRPC authors.
+ *
+ * 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 internal contains code internal to the encoding package.
+package internal
+
+// RegisterCompressorForTesting registers a compressor in the global compressor
+// registry. It returns a cleanup function that should be called at the end
+// of the test to unregister the compressor.
+//
+// This prevents compressors registered in one test from appearing in the
+// encoding headers of subsequent tests.
+var RegisterCompressorForTesting any // func RegisterCompressor(c Compressor) func()

encoding/proto/proto.go

@@ -0,0 +1,112 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * 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 proto defines the protobuf codec. Importing this package will
+// register the codec.
+package proto
+
+import (
+	"fmt"
+
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/mem"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/protoadapt"
+)
+
+// Name is the name registered for the proto compressor.
+const Name = "proto"
+
+func init() {
+	encoding.RegisterCodecV2(&codecV2{})
+}
+
+// codec is a CodecV2 implementation with protobuf. It is the default codec for
+// gRPC.
+type codecV2 struct{}
+
+func (c *codecV2) Marshal(v any) (data mem.BufferSlice, err error) {
+	vv := messageV2Of(v)
+	if vv == nil {
+		return nil, fmt.Errorf("proto: failed to marshal, message is %T, want proto.Message", v)
+	}
+
+	// Important: if we remove this Size call then we cannot use
+	// UseCachedSize in MarshalOptions below.
+	size := proto.Size(vv)
+
+	// MarshalOptions with UseCachedSize allows reusing the result from the
+	// previous Size call. This is safe here because:
+	//
+	// 1. We just computed the size.
+	// 2. We assume the message is not being mutated concurrently.
+	//
+	// Important: If the proto.Size call above is removed, using UseCachedSize
+	// becomes unsafe and may lead to incorrect marshaling.
+	//
+	// For more details, see the doc of UseCachedSize:
+	// https://pkg.go.dev/google.golang.org/protobuf/proto#MarshalOptions
+	marshalOptions := proto.MarshalOptions{UseCachedSize: true}
+
+	if mem.IsBelowBufferPoolingThreshold(size) {
+		buf, err := marshalOptions.Marshal(vv)
+		if err != nil {
+			return nil, err
+		}
+		data = append(data, mem.SliceBuffer(buf))
+	} else {
+		pool := mem.DefaultBufferPool()
+		buf := pool.Get(size)
+		if _, err := marshalOptions.MarshalAppend((*buf)[:0], vv); err != nil {
+			pool.Put(buf)
+			return nil, err
+		}
+		data = append(data, mem.NewBuffer(buf, pool))
+	}
+
+	return data, nil
+}
+
+func (c *codecV2) Unmarshal(data mem.BufferSlice, v any) (err error) {
+	vv := messageV2Of(v)
+	if vv == nil {
+		return fmt.Errorf("failed to unmarshal, message is %T, want proto.Message", v)
+	}
+
+	buf := data.MaterializeToBuffer(mem.DefaultBufferPool())
+	defer buf.Free()
+	// TODO: Upgrade proto.Unmarshal to support mem.BufferSlice. Right now, it's not
+	//  really possible without a major overhaul of the proto package, but the
+	//  vtprotobuf library may be able to support this.
+	return proto.Unmarshal(buf.ReadOnlyData(), vv)
+}
+
+func messageV2Of(v any) proto.Message {
+	switch v := v.(type) {
+	case protoadapt.MessageV1:
+		return protoadapt.MessageV2Of(v)
+	case protoadapt.MessageV2:
+		return v
+	}
+
+	return nil
+}
+
+func (c *codecV2) Name() string {
+	return Name
+}

encoding/proto/proto_benchmark_test.go

@@ -0,0 +1,99 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * 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 proto
+
+import (
+	"fmt"
+	"testing"
+
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/protobuf/proto"
+
+	pb "google.golang.org/grpc/test/codec_perf"
+)
+
+func setupBenchmarkProtoCodecInputs(payloadBaseSize uint32) []proto.Message {
+	payloadBase := make([]byte, payloadBaseSize)
+	// arbitrary byte slices
+	payloadSuffixes := [][]byte{
+		[]byte("one"),
+		[]byte("two"),
+		[]byte("three"),
+		[]byte("four"),
+		[]byte("five"),
+	}
+	protoStructs := make([]proto.Message, 0)
+
+	for _, p := range payloadSuffixes {
+		ps := &pb.Buffer{}
+		ps.Body = append(payloadBase, p...)
+		protoStructs = append(protoStructs, ps)
+	}
+
+	return protoStructs
+}
+
+// The possible use of certain protobuf APIs like the proto.Buffer API potentially involves caching
+// on our side. This can add checks around memory allocations and possible contention.
+// Example run: go test -v -run=^$ -bench=BenchmarkProtoCodec -benchmem
+func BenchmarkProtoCodec(b *testing.B) {
+	// range of message sizes
+	payloadBaseSizes := make([]uint32, 0)
+	for i := uint32(0); i <= 12; i += 4 {
+		payloadBaseSizes = append(payloadBaseSizes, 1<<i)
+	}
+	// range of SetParallelism
+	parallelisms := make([]int, 0)
+	for i := uint32(0); i <= 16; i += 4 {
+		parallelisms = append(parallelisms, int(1<<i))
+	}
+	for _, s := range payloadBaseSizes {
+		for _, p := range parallelisms {
+			protoStructs := setupBenchmarkProtoCodecInputs(s)
+			name := fmt.Sprintf("MinPayloadSize:%v/SetParallelism(%v)", s, p)
+			b.Run(name, func(b *testing.B) {
+				codec := &codecV2{}
+				b.SetParallelism(p)
+				b.RunParallel(func(pb *testing.PB) {
+					benchmarkProtoCodec(codec, protoStructs, pb, b)
+				})
+			})
+		}
+	}
+}
+
+func benchmarkProtoCodec(codec *codecV2, protoStructs []proto.Message, pb *testing.PB, b *testing.B) {
+	counter := 0
+	for pb.Next() {
+		counter++
+		ps := protoStructs[counter%len(protoStructs)]
+		fastMarshalAndUnmarshal(codec, ps, b)
+	}
+}
+
+func fastMarshalAndUnmarshal(codec encoding.CodecV2, protoStruct proto.Message, b *testing.B) {
+	marshaledBytes, err := codec.Marshal(protoStruct)
+	if err != nil {
+		b.Errorf("codec.Marshal(_) returned an error")
+	}
+	res := pb.Buffer{}
+	if err := codec.Unmarshal(marshaledBytes, &res); err != nil {
+		b.Errorf("codec.Unmarshal(_) returned an error")
+	}
+}

encoding/proto/proto_test.go

@@ -0,0 +1,139 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * 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 proto
+
+import (
+	"bytes"
+	"sync"
+	"testing"
+
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/internal/grpctest"
+	"google.golang.org/grpc/mem"
+	pb "google.golang.org/grpc/test/codec_perf"
+)
+
+func marshalAndUnmarshal(t *testing.T, codec encoding.CodecV2, expectedBody []byte) {
+	p := &pb.Buffer{}
+	p.Body = expectedBody
+
+	marshalledBytes, err := codec.Marshal(p)
+	if err != nil {
+		t.Errorf("codec.Marshal(_) returned an error")
+	}
+
+	if err := codec.Unmarshal(marshalledBytes, p); err != nil {
+		t.Errorf("codec.Unmarshal(_) returned an error")
+	}
+
+	if !bytes.Equal(p.GetBody(), expectedBody) {
+		t.Errorf("Unexpected body; got %v; want %v", p.GetBody(), expectedBody)
+	}
+}
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+func (s) TestBasicProtoCodecMarshalAndUnmarshal(t *testing.T) {
+	marshalAndUnmarshal(t, &codecV2{}, []byte{1, 2, 3})
+}
+
+// Try to catch possible race conditions around use of pools
+func (s) TestConcurrentUsage(t *testing.T) {
+	const (
+		numGoRoutines   = 100
+		numMarshUnmarsh = 1000
+	)
+
+	// small, arbitrary byte slices
+	protoBodies := [][]byte{
+		[]byte("one"),
+		[]byte("two"),
+		[]byte("three"),
+		[]byte("four"),
+		[]byte("five"),
+	}
+
+	var wg sync.WaitGroup
+	codec := &codecV2{}
+
+	for i := 0; i < numGoRoutines; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for k := 0; k < numMarshUnmarsh; k++ {
+				marshalAndUnmarshal(t, codec, protoBodies[k%len(protoBodies)])
+			}
+		}()
+	}
+
+	wg.Wait()
+}
+
+// TestStaggeredMarshalAndUnmarshalUsingSamePool tries to catch potential errors in which slices get
+// stomped on during reuse of a proto.Buffer.
+func (s) TestStaggeredMarshalAndUnmarshalUsingSamePool(t *testing.T) {
+	codec1 := &codecV2{}
+	codec2 := &codecV2{}
+
+	expectedBody1 := []byte{1, 2, 3}
+	expectedBody2 := []byte{4, 5, 6}
+
+	proto1 := pb.Buffer{Body: expectedBody1}
+	proto2 := pb.Buffer{Body: expectedBody2}
+
+	var m1, m2 mem.BufferSlice
+	var err error
+
+	if m1, err = codec1.Marshal(&proto1); err != nil {
+		t.Errorf("codec.Marshal(%s) failed", &proto1)
+	}
+
+	if m2, err = codec2.Marshal(&proto2); err != nil {
+		t.Errorf("codec.Marshal(%s) failed", &proto2)
+	}
+
+	if err = codec1.Unmarshal(m1, &proto1); err != nil {
+		t.Errorf("codec.Unmarshal(%v) failed", m1)
+	}
+
+	if err = codec2.Unmarshal(m2, &proto2); err != nil {
+		t.Errorf("codec.Unmarshal(%v) failed", m2)
+	}
+
+	b1 := proto1.GetBody()
+	b2 := proto2.GetBody()
+
+	for i, v := range b1 {
+		if expectedBody1[i] != v {
+			t.Errorf("expected %v at index %v but got %v", i, expectedBody1[i], v)
+		}
+	}
+
+	for i, v := range b2 {
+		if expectedBody2[i] != v {
+			t.Errorf("expected %v at index %v but got %v", i, expectedBody2[i], v)
+		}
+	}
+}