rebase: bump google.golang.org/grpc from 1.50.1 to 1.51.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.50.1 to 1.51.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.50.1...v1.51.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/google.golang.org/grpc/internal/binarylog/env_config.go

@@ -30,15 +30,15 @@ import (
 // to build a new logger and assign it to binarylog.Logger.
 //
 // Example filter config strings:
-//  - "" Nothing will be logged
-//  - "*" All headers and messages will be fully logged.
-//  - "*{h}" Only headers will be logged.
-//  - "*{m:256}" Only the first 256 bytes of each message will be logged.
-//  - "Foo/*" Logs every method in service Foo
-//  - "Foo/*,-Foo/Bar" Logs every method in service Foo except method /Foo/Bar
-//  - "Foo/*,Foo/Bar{m:256}" Logs the first 256 bytes of each message in method
-//    /Foo/Bar, logs all headers and messages in every other method in service
-//    Foo.
+//   - "" Nothing will be logged
+//   - "*" All headers and messages will be fully logged.
+//   - "*{h}" Only headers will be logged.
+//   - "*{m:256}" Only the first 256 bytes of each message will be logged.
+//   - "Foo/*" Logs every method in service Foo
+//   - "Foo/*,-Foo/Bar" Logs every method in service Foo except method /Foo/Bar
+//   - "Foo/*,Foo/Bar{m:256}" Logs the first 256 bytes of each message in method
+//     /Foo/Bar, logs all headers and messages in every other method in service
+//     Foo.
 //
 // If two configs exist for one certain method or service, the one specified
 // later overrides the previous config.

vendor/google.golang.org/grpc/internal/channelz/types.go

@@ -273,10 +273,10 @@ func (c *channel) deleteSelfFromMap() (delete bool) {
 
 // deleteSelfIfReady tries to delete the channel itself from the channelz database.
 // The delete process includes two steps:
-// 1. delete the channel from the entry relation tree, i.e. delete the channel reference from its
-//    parent's child list.
-// 2. delete the channel from the map, i.e. delete the channel entirely from channelz. Lookup by id
-//    will return entry not found error.
+//  1. delete the channel from the entry relation tree, i.e. delete the channel reference from its
+//     parent's child list.
+//  2. delete the channel from the map, i.e. delete the channel entirely from channelz. Lookup by id
+//     will return entry not found error.
 func (c *channel) deleteSelfIfReady() {
 	if !c.deleteSelfFromTree() {
 		return
@@ -381,10 +381,10 @@ func (sc *subChannel) deleteSelfFromMap() (delete bool) {
 
 // deleteSelfIfReady tries to delete the subchannel itself from the channelz database.
 // The delete process includes two steps:
-// 1. delete the subchannel from the entry relation tree, i.e. delete the subchannel reference from
-//    its parent's child list.
-// 2. delete the subchannel from the map, i.e. delete the subchannel entirely from channelz. Lookup
-//    by id will return entry not found error.
+//  1. delete the subchannel from the entry relation tree, i.e. delete the subchannel reference from
+//     its parent's child list.
+//  2. delete the subchannel from the map, i.e. delete the subchannel entirely from channelz. Lookup
+//     by id will return entry not found error.
 func (sc *subChannel) deleteSelfIfReady() {
 	if !sc.deleteSelfFromTree() {
 		return

vendor/google.golang.org/grpc/internal/envconfig/envconfig.go

@@ -25,11 +25,15 @@ import (
 )
 
 const (
-	prefix          = "GRPC_GO_"
-	txtErrIgnoreStr = prefix + "IGNORE_TXT_ERRORS"
+	prefix                  = "GRPC_GO_"
+	txtErrIgnoreStr         = prefix + "IGNORE_TXT_ERRORS"
+	advertiseCompressorsStr = prefix + "ADVERTISE_COMPRESSORS"
 )
 
 var (
 	// TXTErrIgnore is set if TXT errors should be ignored ("GRPC_GO_IGNORE_TXT_ERRORS" is not "false").
 	TXTErrIgnore = !strings.EqualFold(os.Getenv(txtErrIgnoreStr), "false")
+	// AdvertiseCompressors is set if registered compressor should be advertised
+	// ("GRPC_GO_ADVERTISE_COMPRESSORS" is not "false").
+	AdvertiseCompressors = !strings.EqualFold(os.Getenv(advertiseCompressorsStr), "false")
 )

vendor/google.golang.org/grpc/internal/grpclog/grpclog.go

@@ -110,7 +110,7 @@ type LoggerV2 interface {
 // This is a copy of the DepthLoggerV2 defined in the external grpclog package.
 // It is defined here to avoid a circular dependency.
 //
-// Experimental
+// # Experimental
 //
 // Notice: This type is EXPERIMENTAL and may be changed or removed in a
 // later release.

vendor/google.golang.org/grpc/internal/grpcsync/oncefunc.go

@@ -0,0 +1,32 @@
+/*
+ *
+ * Copyright 2022 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 grpcsync
+
+import (
+	"sync"
+)
+
+// OnceFunc returns a function wrapping f which ensures f is only executed
+// once even if the returned function is executed multiple times.
+func OnceFunc(f func()) func() {
+	var once sync.Once
+	return func() {
+		once.Do(f)
+	}
+}

vendor/google.golang.org/grpc/internal/grpcutil/compressor.go

@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2022 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 grpcutil
+
+import (
+	"strings"
+
+	"google.golang.org/grpc/internal/envconfig"
+)
+
+// RegisteredCompressorNames holds names of the registered compressors.
+var RegisteredCompressorNames []string
+
+// IsCompressorNameRegistered returns true when name is available in registry.
+func IsCompressorNameRegistered(name string) bool {
+	for _, compressor := range RegisteredCompressorNames {
+		if compressor == name {
+			return true
+		}
+	}
+	return false
+}
+
+// RegisteredCompressors returns a string of registered compressor names
+// separated by comma.
+func RegisteredCompressors() string {
+	if !envconfig.AdvertiseCompressors {
+		return ""
+	}
+	return strings.Join(RegisteredCompressorNames, ",")
+}

vendor/google.golang.org/grpc/internal/grpcutil/method.go

@@ -25,7 +25,6 @@ import (
 
 // ParseMethod splits service and method from the input. It expects format
 // "/service/method".
-//
 func ParseMethod(methodName string) (service, method string, _ error) {
 	if !strings.HasPrefix(methodName, "/") {
 		return "", "", errors.New("invalid method name: should start with /")

vendor/google.golang.org/grpc/internal/serviceconfig/serviceconfig.go

@@ -67,10 +67,10 @@ func (bc *BalancerConfig) MarshalJSON() ([]byte, error) {
 // ServiceConfig contains a list of loadBalancingConfigs, each with a name and
 // config. This method iterates through that list in order, and stops at the
 // first policy that is supported.
-// - If the config for the first supported policy is invalid, the whole service
-//   config is invalid.
-// - If the list doesn't contain any supported policy, the whole service config
-//   is invalid.
+//   - If the config for the first supported policy is invalid, the whole service
+//     config is invalid.
+//   - If the list doesn't contain any supported policy, the whole service config
+//     is invalid.
 func (bc *BalancerConfig) UnmarshalJSON(b []byte) error {
 	var ir intermediateBalancerConfig
 	err := json.Unmarshal(b, &ir)

vendor/google.golang.org/grpc/internal/status/status.go

@@ -164,3 +164,13 @@ func (e *Error) Is(target error) bool {
 	}
 	return proto.Equal(e.s.s, tse.s.s)
 }
+
+// IsRestrictedControlPlaneCode returns whether the status includes a code
+// restricted for control plane usage as defined by gRFC A54.
+func IsRestrictedControlPlaneCode(s *Status) bool {
+	switch s.Code() {
+	case codes.InvalidArgument, codes.NotFound, codes.AlreadyExists, codes.FailedPrecondition, codes.Aborted, codes.OutOfRange, codes.DataLoss:
+		return true
+	}
+	return false
+}

vendor/google.golang.org/grpc/internal/transport/handler_server.go

@@ -442,10 +442,10 @@ func (ht *serverHandlerTransport) Drain() {
 // mapRecvMsgError returns the non-nil err into the appropriate
 // error value as expected by callers of *grpc.parser.recvMsg.
 // In particular, in can only be:
-//   * io.EOF
-//   * io.ErrUnexpectedEOF
-//   * of type transport.ConnectionError
-//   * an error from the status package
+//   - io.EOF
+//   - io.ErrUnexpectedEOF
+//   - of type transport.ConnectionError
+//   - an error from the status package
 func mapRecvMsgError(err error) error {
 	if err == io.EOF || err == io.ErrUnexpectedEOF {
 		return err

vendor/google.golang.org/grpc/internal/transport/http2_client.go

@@ -38,8 +38,10 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/internal/channelz"
 	icredentials "google.golang.org/grpc/internal/credentials"
+	"google.golang.org/grpc/internal/grpcsync"
 	"google.golang.org/grpc/internal/grpcutil"
 	imetadata "google.golang.org/grpc/internal/metadata"
+	istatus "google.golang.org/grpc/internal/status"
 	"google.golang.org/grpc/internal/syscall"
 	"google.golang.org/grpc/internal/transport/networktype"
 	"google.golang.org/grpc/keepalive"
@@ -99,16 +101,13 @@ type http2Client struct {
 	maxSendHeaderListSize *uint32
 
 	bdpEst *bdpEstimator
-	// onPrefaceReceipt is a callback that client transport calls upon
-	// receiving server preface to signal that a succefull HTTP2
-	// connection was established.
-	onPrefaceReceipt func()
 
 	maxConcurrentStreams  uint32
 	streamQuota           int64
 	streamsQuotaAvailable chan struct{}
 	waitingStreams        uint32
 	nextID                uint32
+	registeredCompressors string
 
 	// Do not access controlBuf with mu held.
 	mu            sync.Mutex // guard the following variables
@@ -194,7 +193,7 @@ func isTemporary(err error) bool {
 // newHTTP2Client constructs a connected ClientTransport to addr based on HTTP2
 // and starts to receive messages on it. Non-nil error returns if construction
 // fails.
-func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts ConnectOptions, onPrefaceReceipt func(), onGoAway func(GoAwayReason), onClose func()) (_ *http2Client, err error) {
+func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts ConnectOptions, onGoAway func(GoAwayReason), onClose func()) (_ *http2Client, err error) {
 	scheme := "http"
 	ctx, cancel := context.WithCancel(ctx)
 	defer func() {
@@ -216,12 +215,35 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		}
 		return nil, connectionErrorf(true, err, "transport: Error while dialing %v", err)
 	}
+
 	// Any further errors will close the underlying connection
 	defer func(conn net.Conn) {
 		if err != nil {
 			conn.Close()
 		}
 	}(conn)
+
+	// The following defer and goroutine monitor the connectCtx for cancelation
+	// and deadline.  On context expiration, the connection is hard closed and
+	// this function will naturally fail as a result.  Otherwise, the defer
+	// waits for the goroutine to exit to prevent the context from being
+	// monitored (and to prevent the connection from ever being closed) after
+	// returning from this function.
+	ctxMonitorDone := grpcsync.NewEvent()
+	newClientCtx, newClientDone := context.WithCancel(connectCtx)
+	defer func() {
+		newClientDone()         // Awaken the goroutine below if connectCtx hasn't expired.
+		<-ctxMonitorDone.Done() // Wait for the goroutine below to exit.
+	}()
+	go func(conn net.Conn) {
+		defer ctxMonitorDone.Fire() // Signal this goroutine has exited.
+		<-newClientCtx.Done()       // Block until connectCtx expires or the defer above executes.
+		if connectCtx.Err() != nil {
+			// connectCtx expired before exiting the function.  Hard close the connection.
+			conn.Close()
+		}
+	}(conn)
+
 	kp := opts.KeepaliveParams
 	// Validate keepalive parameters.
 	if kp.Time == 0 {
@@ -253,15 +275,7 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		}
 	}
 	if transportCreds != nil {
-		rawConn := conn
-		// Pull the deadline from the connectCtx, which will be used for
-		// timeouts in the authentication protocol handshake. Can ignore the
-		// boolean as the deadline will return the zero value, which will make
-		// the conn not timeout on I/O operations.
-		deadline, _ := connectCtx.Deadline()
-		rawConn.SetDeadline(deadline)
-		conn, authInfo, err = transportCreds.ClientHandshake(connectCtx, addr.ServerName, rawConn)
-		rawConn.SetDeadline(time.Time{})
+		conn, authInfo, err = transportCreds.ClientHandshake(connectCtx, addr.ServerName, conn)
 		if err != nil {
 			return nil, connectionErrorf(isTemporary(err), err, "transport: authentication handshake failed: %v", err)
 		}
@@ -299,6 +313,7 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		ctxDone:               ctx.Done(), // Cache Done chan.
 		cancel:                cancel,
 		userAgent:             opts.UserAgent,
+		registeredCompressors: grpcutil.RegisteredCompressors(),
 		conn:                  conn,
 		remoteAddr:            conn.RemoteAddr(),
 		localAddr:             conn.LocalAddr(),
@@ -315,16 +330,15 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		kp:                    kp,
 		statsHandlers:         opts.StatsHandlers,
 		initialWindowSize:     initialWindowSize,
-		onPrefaceReceipt:      onPrefaceReceipt,
 		nextID:                1,
 		maxConcurrentStreams:  defaultMaxStreamsClient,
 		streamQuota:           defaultMaxStreamsClient,
 		streamsQuotaAvailable: make(chan struct{}, 1),
 		czData:                new(channelzData),
 		onGoAway:              onGoAway,
-		onClose:               onClose,
 		keepaliveEnabled:      keepaliveEnabled,
 		bufferPool:            newBufferPool(),
+		onClose:               onClose,
 	}
 	// Add peer information to the http2client context.
 	t.ctx = peer.NewContext(t.ctx, t.getPeer())
@@ -363,21 +377,32 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		t.kpDormancyCond = sync.NewCond(&t.mu)
 		go t.keepalive()
 	}
-	// Start the reader goroutine for incoming message. Each transport has
-	// a dedicated goroutine which reads HTTP2 frame from network. Then it
-	// dispatches the frame to the corresponding stream entity.
-	go t.reader()
+
+	// Start the reader goroutine for incoming messages. Each transport has a
+	// dedicated goroutine which reads HTTP2 frames from the network. Then it
+	// dispatches the frame to the corresponding stream entity.  When the
+	// server preface is received, readerErrCh is closed.  If an error occurs
+	// first, an error is pushed to the channel.  This must be checked before
+	// returning from this function.
+	readerErrCh := make(chan error, 1)
+	go t.reader(readerErrCh)
+	defer func() {
+		if err == nil {
+			err = <-readerErrCh
+		}
+		if err != nil {
+			t.Close(err)
+		}
+	}()
 
 	// Send connection preface to server.
 	n, err := t.conn.Write(clientPreface)
 	if err != nil {
 		err = connectionErrorf(true, err, "transport: failed to write client preface: %v", err)
-		t.Close(err)
 		return nil, err
 	}
 	if n != len(clientPreface) {
 		err = connectionErrorf(true, nil, "transport: preface mismatch, wrote %d bytes; want %d", n, len(clientPreface))
-		t.Close(err)
 		return nil, err
 	}
 	var ss []http2.Setting
@@ -397,14 +422,12 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 	err = t.framer.fr.WriteSettings(ss...)
 	if err != nil {
 		err = connectionErrorf(true, err, "transport: failed to write initial settings frame: %v", err)
-		t.Close(err)
 		return nil, err
 	}
 	// Adjust the connection flow control window if needed.
 	if delta := uint32(icwz - defaultWindowSize); delta > 0 {
 		if err := t.framer.fr.WriteWindowUpdate(0, delta); err != nil {
 			err = connectionErrorf(true, err, "transport: failed to write window update: %v", err)
-			t.Close(err)
 			return nil, err
 		}
 	}
@@ -507,9 +530,22 @@ func (t *http2Client) createHeaderFields(ctx context.Context, callHdr *CallHdr)
 		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-previous-rpc-attempts", Value: strconv.Itoa(callHdr.PreviousAttempts)})
 	}
 
+	registeredCompressors := t.registeredCompressors
 	if callHdr.SendCompress != "" {
 		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-encoding", Value: callHdr.SendCompress})
-		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-accept-encoding", Value: callHdr.SendCompress})
+		// Include the outgoing compressor name when compressor is not registered
+		// via encoding.RegisterCompressor. This is possible when client uses
+		// WithCompressor dial option.
+		if !grpcutil.IsCompressorNameRegistered(callHdr.SendCompress) {
+			if registeredCompressors != "" {
+				registeredCompressors += ","
+			}
+			registeredCompressors += callHdr.SendCompress
+		}
+	}
+
+	if registeredCompressors != "" {
+		headerFields = append(headerFields, hpack.HeaderField{Name: "grpc-accept-encoding", Value: registeredCompressors})
 	}
 	if dl, ok := ctx.Deadline(); ok {
 		// Send out timeout regardless its value. The server can detect timeout context by itself.
@@ -589,7 +625,11 @@ func (t *http2Client) getTrAuthData(ctx context.Context, audience string) (map[s
 	for _, c := range t.perRPCCreds {
 		data, err := c.GetRequestMetadata(ctx, audience)
 		if err != nil {
-			if _, ok := status.FromError(err); ok {
+			if st, ok := status.FromError(err); ok {
+				// Restrict the code to the list allowed by gRFC A54.
+				if istatus.IsRestrictedControlPlaneCode(st) {
+					err = status.Errorf(codes.Internal, "transport: received per-RPC creds error with illegal status: %v", err)
+				}
 				return nil, err
 			}
 
@@ -618,7 +658,14 @@ func (t *http2Client) getCallAuthData(ctx context.Context, audience string, call
 		}
 		data, err := callCreds.GetRequestMetadata(ctx, audience)
 		if err != nil {
-			return nil, status.Errorf(codes.Internal, "transport: %v", err)
+			if st, ok := status.FromError(err); ok {
+				// Restrict the code to the list allowed by gRFC A54.
+				if istatus.IsRestrictedControlPlaneCode(st) {
+					err = status.Errorf(codes.Internal, "transport: received per-RPC creds error with illegal status: %v", err)
+				}
+				return nil, err
+			}
+			return nil, status.Errorf(codes.Internal, "transport: per-RPC creds failed due to error: %v", err)
 		}
 		callAuthData = make(map[string]string, len(data))
 		for k, v := range data {
@@ -634,13 +681,13 @@ func (t *http2Client) getCallAuthData(ctx context.Context, audience string, call
 // NewStream errors result in transparent retry, as they mean nothing went onto
 // the wire.  However, there are two notable exceptions:
 //
-// 1. If the stream headers violate the max header list size allowed by the
-//    server.  It's possible this could succeed on another transport, even if
-//    it's unlikely, but do not transparently retry.
-// 2. If the credentials errored when requesting their headers.  In this case,
-//    it's possible a retry can fix the problem, but indefinitely transparently
-//    retrying is not appropriate as it is likely the credentials, if they can
-//    eventually succeed, would need I/O to do so.
+//  1. If the stream headers violate the max header list size allowed by the
+//     server.  It's possible this could succeed on another transport, even if
+//     it's unlikely, but do not transparently retry.
+//  2. If the credentials errored when requesting their headers.  In this case,
+//     it's possible a retry can fix the problem, but indefinitely transparently
+//     retrying is not appropriate as it is likely the credentials, if they can
+//     eventually succeed, would need I/O to do so.
 type NewStreamError struct {
 	Err error
 
@@ -880,19 +927,15 @@ func (t *http2Client) closeStream(s *Stream, err error, rst bool, rstCode http2.
 // Close kicks off the shutdown process of the transport. This should be called
 // only once on a transport. Once it is called, the transport should not be
 // accessed any more.
-//
-// This method blocks until the addrConn that initiated this transport is
-// re-connected. This happens because t.onClose() begins reconnect logic at the
-// addrConn level and blocks until the addrConn is successfully connected.
 func (t *http2Client) Close(err error) {
 	t.mu.Lock()
-	// Make sure we only Close once.
+	// Make sure we only close once.
 	if t.state == closing {
 		t.mu.Unlock()
 		return
 	}
-	// Call t.onClose before setting the state to closing to prevent the client
-	// from attempting to create new streams ASAP.
+	// Call t.onClose ASAP to prevent the client from attempting to create new
+	// streams.
 	t.onClose()
 	t.state = closing
 	streams := t.activeStreams
@@ -1482,33 +1525,35 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	t.closeStream(s, io.EOF, rst, http2.ErrCodeNo, statusGen, mdata, true)
 }
 
-// reader runs as a separate goroutine in charge of reading data from network
-// connection.
-//
-// TODO(zhaoq): currently one reader per transport. Investigate whether this is
-// optimal.
-// TODO(zhaoq): Check the validity of the incoming frame sequence.
-func (t *http2Client) reader() {
-	defer close(t.readerDone)
-	// Check the validity of server preface.
+// readServerPreface reads and handles the initial settings frame from the
+// server.
+func (t *http2Client) readServerPreface() error {
 	frame, err := t.framer.fr.ReadFrame()
 	if err != nil {
-		err = connectionErrorf(true, err, "error reading server preface: %v", err)
-		t.Close(err) // this kicks off resetTransport, so must be last before return
-		return
-	}
-	t.conn.SetReadDeadline(time.Time{}) // reset deadline once we get the settings frame (we didn't time out, yay!)
-	if t.keepaliveEnabled {
-		atomic.StoreInt64(&t.lastRead, time.Now().UnixNano())
+		return connectionErrorf(true, err, "error reading server preface: %v", err)
 	}
 	sf, ok := frame.(*http2.SettingsFrame)
 	if !ok {
-		// this kicks off resetTransport, so must be last before return
-		t.Close(connectionErrorf(true, nil, "initial http2 frame from server is not a settings frame: %T", frame))
+		return connectionErrorf(true, nil, "initial http2 frame from server is not a settings frame: %T", frame)
+	}
+	t.handleSettings(sf, true)
+	return nil
+}
+
+// reader verifies the server preface and reads all subsequent data from
+// network connection.  If the server preface is not read successfully, an
+// error is pushed to errCh; otherwise errCh is closed with no error.
+func (t *http2Client) reader(errCh chan<- error) {
+	defer close(t.readerDone)
+
+	if err := t.readServerPreface(); err != nil {
+		errCh <- err
 		return
 	}
-	t.onPrefaceReceipt()
-	t.handleSettings(sf, true)
+	close(errCh)
+	if t.keepaliveEnabled {
+		atomic.StoreInt64(&t.lastRead, time.Now().UnixNano())
+	}
 
 	// loop to keep reading incoming messages on this transport.
 	for {

vendor/google.golang.org/grpc/internal/transport/transport.go

@@ -43,6 +43,10 @@ import (
 	"google.golang.org/grpc/tap"
 )
 
+// ErrNoHeaders is used as a signal that a trailers only response was received,
+// and is not a real error.
+var ErrNoHeaders = errors.New("stream has no headers")
+
 const logLevel = 2
 
 type bufferPool struct {
@@ -366,9 +370,15 @@ func (s *Stream) Header() (metadata.MD, error) {
 		return s.header.Copy(), nil
 	}
 	s.waitOnHeader()
+
 	if !s.headerValid {
 		return nil, s.status.Err()
 	}
+
+	if s.noHeaders {
+		return nil, ErrNoHeaders
+	}
+
 	return s.header.Copy(), nil
 }
 
@@ -573,8 +583,8 @@ type ConnectOptions struct {
 
 // NewClientTransport establishes the transport with the required ConnectOptions
 // and returns it to the caller.
-func NewClientTransport(connectCtx, ctx context.Context, addr resolver.Address, opts ConnectOptions, onPrefaceReceipt func(), onGoAway func(GoAwayReason), onClose func()) (ClientTransport, error) {
-	return newHTTP2Client(connectCtx, ctx, addr, opts, onPrefaceReceipt, onGoAway, onClose)
+func NewClientTransport(connectCtx, ctx context.Context, addr resolver.Address, opts ConnectOptions, onGoAway func(GoAwayReason), onClose func()) (ClientTransport, error) {
+	return newHTTP2Client(connectCtx, ctx, addr, opts, onGoAway, onClose)
 }
 
 // Options provides additional hints and information for message