client: make handshake required 'on' by default, not 'hybrid'

dialoptions.go

@@ -95,10 +95,8 @@ func newFuncDialOption(f func(*dialOptions)) *funcDialOption {
 // WithWaitForHandshake blocks until the initial settings frame is received from
 // the server before assigning RPCs to the connection.
 //
-// Deprecated: this will become the default behavior in the 1.18 release, and
-// will be removed after the 1.18 release.  To override the default behavior in
-// the 1.18 release, either use this dial option or set the environment
-// variable GRPC_GO_READY_BEFORE_HANDSHAKE=on.
+// Deprecated: this is the default behavior, and this option will be removed
+// after the 1.18 release.
 func WithWaitForHandshake() DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.reqHandshake = envconfig.RequireHandshakeOn

internal/envconfig/envconfig.go

@@ -59,6 +59,7 @@ var (
 func init() {
 	switch strings.ToLower(os.Getenv(requireHandshakeStr)) {
 	case "on":
+	default:
 		RequireHandshake = RequireHandshakeOn
 	case "off":
 		RequireHandshake = RequireHandshakeOff

test/channelz_test.go

@@ -1655,7 +1655,6 @@ func (s) TestCZSubChannelConnectivityState(t *testing.T) {
 	defer cleanup()
 	r.InitialAddrs([]resolver.Address{{Addr: te.srvAddr}})
 	te.resolverScheme = r.Scheme()
-	te.customDialOptions = []grpc.DialOption{grpc.WithWaitForHandshake()}
 	cc := te.clientConn()
 	defer te.tearDown()
 	tc := testpb.NewTestServiceClient(cc)
@@ -1750,7 +1749,6 @@ func (s) TestCZChannelConnectivityState(t *testing.T) {
 	defer cleanup()
 	r.InitialAddrs([]resolver.Address{{Addr: te.srvAddr}})
 	te.resolverScheme = r.Scheme()
-	te.customDialOptions = []grpc.DialOption{grpc.WithWaitForHandshake()}
 	cc := te.clientConn()
 	defer te.tearDown()
 	tc := testpb.NewTestServiceClient(cc)

test/end2end_test.go

@@ -969,7 +969,6 @@ func (s) TestTimeoutOnDeadServer(t *testing.T) {
 
 func testTimeoutOnDeadServer(t *testing.T, e env) {
 	te := newTest(t, e)
-	te.customDialOptions = []grpc.DialOption{grpc.WithWaitForHandshake()}
 	te.userAgent = testAppUA
 	te.declareLogNoise(
 		"transport: http2Client.notifyError got notified that the client transport was broken EOF",

test/gracefulstop_test.go

@@ -29,6 +29,7 @@ import (
 
 	"google.golang.org/grpc"
 
+	"google.golang.org/grpc/internal/envconfig"
 	testpb "google.golang.org/grpc/test/grpc_testing"
 )
 
@@ -106,6 +107,11 @@ func (d *delayConn) Read(b []byte) (n int, err error) {
 }
 
 func (s) TestGracefulStop(t *testing.T) {
+	// Set default behavior and restore current setting after test.
+	old := envconfig.RequireHandshake
+	envconfig.RequireHandshake = envconfig.RequireHandshakeOff
+	defer func() { envconfig.RequireHandshake = old }()
+
 	// This test ensures GracefulStop cannot race and break RPCs on new
 	// connections created after GracefulStop was called but before
 	// listener.Accept() returns a "closing" error.
@@ -176,6 +182,7 @@ func (s) TestGracefulStop(t *testing.T) {
 	defer dialCancel()
 	cc, err := grpc.DialContext(ctx, "", grpc.WithInsecure(), grpc.WithBlock(), grpc.WithDialer(d))
 	if err != nil {
+		dlis.allowClientRead()
 		t.Fatalf("grpc.Dial(%q) = %v", lis.Addr().String(), err)
 	}
 	client := testpb.NewTestServiceClient(cc)

test/healthcheck_test.go

@@ -387,7 +387,6 @@ func (s) TestHealthCheckWithConnClose(t *testing.T) {
 	cc, r, deferFunc, err := setupClient(&clientConfig{
 		balancerName:               "round_robin",
 		testHealthCheckFuncWrapper: testHealthCheckFuncWrapper,
-		extraDialOption:            []grpc.DialOption{grpc.WithWaitForHandshake()},
 	})
 	if err != nil {
 		t.Fatal(err)
@@ -689,7 +688,6 @@ func (s) TestHealthCheckWithoutReportHealthCalled(t *testing.T) {
 	_, r, deferFunc, err := setupClient(&clientConfig{
 		balancerName:               "round_robin",
 		testHealthCheckFuncWrapper: testHealthCheckFuncWrapper,
-		extraDialOption:            []grpc.DialOption{grpc.WithWaitForHandshake()},
 	})
 	if err != nil {
 		t.Fatal(err)