fix review comments

Author: menghanl

Diff for: balancer/grpclb/grpclb_remote_balancer.go

@@ -272,7 +272,7 @@ func (lb *lbBalancer) dialRemoteLB(remoteLBName string) {
 			dopts = append(dopts, grpc.WithInsecure())
 		}
 	} else if bundle := lb.grpclbClientConnCreds; bundle != nil {
-		dopts = append(dopts, grpc.WithCreds(bundle))
+		dopts = append(dopts, grpc.WithCredentialsBundle(bundle))
 	} else {
 		dopts = append(dopts, grpc.WithInsecure())
 	}

Diff for: credentials/google/google.go

@@ -86,11 +86,13 @@ func (c *creds) SwitchMode(mode string) (credentials.Bundle, error) {
 		newCreds.transportCreds = credentials.NewTLS(nil)
 	case internal.CredsBundleModeALTS, internal.CredsBundleModeGRPCLB:
 		if !vmOnGCP {
-			return nil, errors.New("ALTS, as part of google default credentials, is only supported on GCP")
+			return nil, errors.New("google default creds: ALTS, as part of google default credentials, is only supported on GCP")
 		}
+		// Only the clients can use google default credentials, so we only need
+		// to create new ALTS client creds here.
 		newCreds.transportCreds = alts.NewClientCreds(alts.DefaultClientOptions())
 	default:
-		return nil, fmt.Errorf("unsupported mode: %v", mode)
+		return nil, fmt.Errorf("google default creds: unsupported mode: %v", mode)
 	}
 
 	// Create per RPC credentials.

Diff for: dialoptions.go

@@ -302,12 +302,12 @@ func WithPerRPCCredentials(creds credentials.PerRPCCredentials) DialOption {
 	})
 }
 
-// WithCreds returns a DialOption to set a credentials bundle for the
-// ClientConn.WithCreds. This should not be used together with
+// WithCredentialsBundle returns a DialOption to set a credentials bundle for
+// the ClientConn.WithCreds. This should not be used together with
 // WithTransportCredentials.
 //
 // This API is experimental.
-func WithCreds(b credentials.Bundle) DialOption {
+func WithCredentialsBundle(b credentials.Bundle) DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.copts.CredsBundle = b
 	})

Diff for: internal/transport/http2_client.go

@@ -169,21 +169,21 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr TargetInfo, opts Conne
 		isSecure bool
 		authInfo credentials.AuthInfo
 	)
-	var creds credentials.TransportCredentials
+	var transportCreds credentials.TransportCredentials
 	perRPCCreds := opts.PerRPCCredentials
 
 	if b := opts.CredsBundle; b != nil {
-		creds = b.TransportCredentials()
+		transportCreds = b.TransportCredentials()
 		if t := b.PerRPCCredentials(); t != nil {
 			perRPCCreds = append(perRPCCreds, t)
 		}
 	}
-	if creds == nil {
-		creds = opts.TransportCredentials
+	if transportCreds == nil {
+		transportCreds = opts.TransportCredentials
 	}
-	if creds != nil {
+	if transportCreds != nil {
 		scheme = "https"
-		conn, authInfo, err = creds.ClientHandshake(connectCtx, addr.Authority, conn)
+		conn, authInfo, err = transportCreds.ClientHandshake(connectCtx, addr.Authority, conn)
 		if err != nil {
 			return nil, connectionErrorf(isTemporary(err), err, "transport: authentication handshake failed: %v", err)
 		}

Diff for: interop/client/client.go

@@ -107,7 +107,7 @@ func main() {
 		altsTC := alts.NewClientCreds(altsOpts)
 		opts = append(opts, grpc.WithTransportCredentials(altsTC))
 	} else if *useGoogleDefaultCreds {
-		opts = append(opts, grpc.WithCreds(google.NewDefaultCredentials()))
+		opts = append(opts, grpc.WithCredentialsBundle(google.NewDefaultCredentials()))
 	} else {
 		opts = append(opts, grpc.WithInsecure())
 	}

Diff for: test/creds_test.go

@@ -70,7 +70,7 @@ func TestCredsBundleBoth(t *testing.T) {
 	te := newTest(t, env{name: "creds-bundle", network: "tcp", balancer: "v1", security: "empty"})
 	te.tapHandle = authHandle
 	te.customDialOptions = []grpc.DialOption{
-		grpc.WithCreds(&testCredsBundle{t: t}),
+		grpc.WithCredentialsBundle(&testCredsBundle{t: t}),
 	}
 	creds, err := credentials.NewServerTLSFromFile(testdata.Path("server1.pem"), testdata.Path("server1.key"))
 	if err != nil {
@@ -93,7 +93,7 @@ func TestCredsBundleTransportCredentials(t *testing.T) {
 	defer leakcheck.Check(t)
 	te := newTest(t, env{name: "creds-bundle", network: "tcp", balancer: "v1", security: "empty"})
 	te.customDialOptions = []grpc.DialOption{
-		grpc.WithCreds(&testCredsBundle{t: t, mode: bundleTLSOnly}),
+		grpc.WithCredentialsBundle(&testCredsBundle{t: t, mode: bundleTLSOnly}),
 	}
 	creds, err := credentials.NewServerTLSFromFile(testdata.Path("server1.pem"), testdata.Path("server1.key"))
 	if err != nil {
@@ -117,7 +117,7 @@ func TestCredsBundlePerRPCCredentials(t *testing.T) {
 	te := newTest(t, env{name: "creds-bundle", network: "tcp", balancer: "v1", security: "empty"})
 	te.tapHandle = authHandle
 	te.customDialOptions = []grpc.DialOption{
-		grpc.WithCreds(&testCredsBundle{t: t, mode: bundlePerRPCOnly}),
+		grpc.WithCredentialsBundle(&testCredsBundle{t: t, mode: bundlePerRPCOnly}),
 	}
 	te.startServer(&testServer{})
 	defer te.tearDown()