fix(internal/gengapic): add API version to client comment

internal/gengapic/client_init.go

@@ -154,7 +154,7 @@ func (g *generator) internalClientIntfInit(serv *descriptorpb.ServiceDescriptorP
 }
 
 // serviceDoc is a helper function similar to methodDoc that includes a deprecation notice for deprecated services.
-func (g *generator) serviceDoc(serv *descriptorpb.ServiceDescriptorProto) {
+func (g *generator) serviceDoc(serv *descriptorpb.ServiceDescriptorProto, includeAPIVersion bool) {
 	com := g.comments[serv]
 
 	// If there's no comment and the service is not deprecated, return.
@@ -184,6 +184,12 @@ func (g *generator) serviceDoc(serv *descriptorpb.ServiceDescriptorProto) {
 	// Prepend new line break before existing service comments.
 	g.printf("//")
 	g.comment(com)
+
+	apiVersion := proto.GetExtension(serv.Options, annotations.E_ApiVersion).(string)
+	if apiVersion != "" && includeAPIVersion {
+		g.printf("//")
+		g.comment(fmt.Sprintf("This client uses %s version %s.", serv.GetName(), apiVersion))
+	}
 }
 
 func (g *generator) clientInit(serv *descriptorpb.ServiceDescriptorProto, servName string, hasRPCForLRO bool) {
@@ -192,7 +198,7 @@ func (g *generator) clientInit(serv *descriptorpb.ServiceDescriptorProto, servNa
 	// client struct
 	p("// %sClient is a client for interacting with %s.", servName, g.apiName)
 	p("// Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.")
-	g.serviceDoc(serv)
+	g.serviceDoc(serv, true) // include API version docs
 	p("type %sClient struct {", servName)
 
 	// Fields

internal/gengapic/client_init_test.go

@@ -260,16 +260,21 @@ func TestClientOpt(t *testing.T) {
 }
 
 func TestServiceDoc(t *testing.T) {
+	sOpts := &descriptorpb.ServiceOptions{}
+	proto.SetExtension(sOpts, annotations.E_ApiVersion, "2024-09-14")
+
 	serv := &descriptorpb.ServiceDescriptorProto{
-		Name: proto.String("MyService"),
+		Name:    proto.String("MyService"),
+		Options: sOpts,
 	}
 
 	var g generator
 	g.comments = make(map[protoiface.MessageV1]string)
 
 	for _, tst := range []struct {
-		in, want   string
-		deprecated bool
+		in, want          string
+		deprecated        bool
+		includeAPIVersion bool
 	}{
 		{
 			in:   "",
@@ -279,6 +284,11 @@ func TestServiceDoc(t *testing.T) {
 			in:   "Does stuff.\n It also does other stuffs.",
 			want: "//\n// Does stuff.\n// It also does other stuffs.\n",
 		},
+		{
+			in:                "Does stuff.\n It also does other stuffs.",
+			want:              "//\n// Does stuff.\n// It also does other stuffs.\n//\n// This client uses MyService version 2024-09-14.\n",
+			includeAPIVersion: true,
+		},
 		{
 			in:         "This is deprecated.\n It does not have a proper comment.",
 			want:       "//\n// This is deprecated.\n// It does not have a proper comment.\n//\n// Deprecated: MyService may be removed in a future version.\n",
@@ -301,11 +311,10 @@ func TestServiceDoc(t *testing.T) {
 		},
 	} {
 		g.comments[serv] = tst.in
-		serv.Options = &descriptorpb.ServiceOptions{
-			Deprecated: proto.Bool(tst.deprecated),
-		}
+		serv.Options.Deprecated = proto.Bool(tst.deprecated)
+
 		g.pt.Reset()
-		g.serviceDoc(serv)
+		g.serviceDoc(serv, tst.includeAPIVersion)
 		if diff := cmp.Diff(g.pt.String(), tst.want); diff != "" {
 			t.Errorf("comment() got(-),want(+):\n%s", diff)
 		}

internal/gengapic/gengrpc.go

@@ -326,7 +326,7 @@ func (g *generator) grpcClientUtilities(serv *descriptorpb.ServiceDescriptorProt
 	// Factory function
 	p("// New%sClient creates a new %s client based on gRPC.", servName, clientName)
 	p("// The returned client must be Closed when it is done being used to clean up its underlying connections.")
-	g.serviceDoc(serv)
+	g.serviceDoc(serv, false) // exclude API version docs
 	p("func New%[1]sClient(ctx context.Context, opts ...option.ClientOption) (*%[1]sClient, error) {", servName)
 	p("  clientOpts := default%[1]sGRPCClientOptions()", servName)
 

internal/gengapic/genrest.go

@@ -159,7 +159,7 @@ func (g *generator) restClientUtilities(serv *descriptorpb.ServiceDescriptorProt
 	opServ, hasCustomOp := g.customOpServices[serv]
 
 	p("// New%sRESTClient creates a new %s rest client.", servName, clientName)
-	g.serviceDoc(serv)
+	g.serviceDoc(serv, false) // exclude API version docs
 	p("func New%[1]sRESTClient(ctx context.Context, opts ...option.ClientOption) (*%[1]sClient, error) {", servName)
 	p("    clientOpts := append(default%sRESTClientOptions(), opts...)", servName)
 	p("    httpClient, endpoint, err := httptransport.NewClient(ctx, clientOpts...)")

internal/gengapic/testdata/empty_client_init.want

@@ -10,6 +10,8 @@ type internalClient interface {
 // Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
 //
 // Foo service does stuff.
+//
+// This client uses Foo version v1_20240425.
 type Client struct {
 	// The internal transport-dependent client.
 	internalClient internalClient

internal/gengapic/testdata/foo_client_init.want

@@ -15,6 +15,8 @@ type internalFooClient interface {
 // Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
 //
 // Foo service does stuff.
+//
+// This client uses Foo version v1_20240425.
 type FooClient struct {
 	// The internal transport-dependent client.
 	internalClient internalFooClient

internal/gengapic/testdata/foo_rest_client_init.want

@@ -15,6 +15,8 @@ type internalFooClient interface {
 // Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
 //
 // Foo service does stuff.
+//
+// This client uses Foo version v1_20240425.
 type FooClient struct {
 	// The internal transport-dependent client.
 	internalClient internalFooClient

internal/gengapic/testdata/lro_client_init.want

@@ -16,6 +16,8 @@ type internalFooClient interface {
 // Methods, except Close, may be called concurrently. However, fields must not be modified concurrently with method calls.
 //
 // Foo service does stuff.
+//
+// This client uses Foo version v1_20240425.
 type FooClient struct {
 	// The internal transport-dependent client.
 	internalClient internalFooClient