protoc-gen-go: simplify init function generation (#716)

We generate a single init function containing registration calls for
all the things in a .pb.go that need one (messages, extensions, etc.)

Some of these registrations are added to a list as the generator processes
the type that needs to be registered (e.g., messages.) Some are added at
the end while generating the init function (e.g., enums). Extensions
are done in both places.

Make this consistent and always generate the registration functions
during processing. This simplifies the code a bit, and makes it easier
for a new generator to be consistent with its output.

No changes to the number of init functions, just the order of
registration calls in the existing one.

conformance/internal/conformance_proto/conformance.pb.go

@@ -1648,6 +1648,9 @@ func (m *ForeignMessage) GetC() int32 {
 }
 
 func init() {
+	proto.RegisterEnum("conformance.WireFormat", WireFormat_name, WireFormat_value)
+	proto.RegisterEnum("conformance.ForeignEnum", ForeignEnum_name, ForeignEnum_value)
+	proto.RegisterEnum("conformance.TestAllTypes_NestedEnum", TestAllTypes_NestedEnum_name, TestAllTypes_NestedEnum_value)
 	proto.RegisterType((*ConformanceRequest)(nil), "conformance.ConformanceRequest")
 	proto.RegisterType((*ConformanceResponse)(nil), "conformance.ConformanceResponse")
 	proto.RegisterType((*TestAllTypes)(nil), "conformance.TestAllTypes")
@@ -1672,9 +1675,6 @@ func init() {
 	proto.RegisterMapType((map[uint64]uint64)(nil), "conformance.TestAllTypes.MapUint64Uint64Entry")
 	proto.RegisterType((*TestAllTypes_NestedMessage)(nil), "conformance.TestAllTypes.NestedMessage")
 	proto.RegisterType((*ForeignMessage)(nil), "conformance.ForeignMessage")
-	proto.RegisterEnum("conformance.WireFormat", WireFormat_name, WireFormat_value)
-	proto.RegisterEnum("conformance.ForeignEnum", ForeignEnum_name, ForeignEnum_value)
-	proto.RegisterEnum("conformance.TestAllTypes_NestedEnum", TestAllTypes_NestedEnum_name, TestAllTypes_NestedEnum_value)
 }
 
 func init() { proto.RegisterFile("conformance.proto", fileDescriptor_e7c910178d599565) }

jsonpb/jsonpb_test_proto/more_test_objects.pb.go

@@ -316,6 +316,7 @@ func (m *Mappy) GetU64Booly() map[uint64]bool {
 }
 
 func init() {
+	proto.RegisterEnum("jsonpb.Numeral", Numeral_name, Numeral_value)
 	proto.RegisterType((*Simple3)(nil), "jsonpb.Simple3")
 	proto.RegisterType((*SimpleSlice3)(nil), "jsonpb.SimpleSlice3")
 	proto.RegisterType((*SimpleMap3)(nil), "jsonpb.SimpleMap3")
@@ -332,7 +333,6 @@ func init() {
 	proto.RegisterMapType((map[string]string)(nil), "jsonpb.Mappy.StrryEntry")
 	proto.RegisterMapType((map[uint32]bool)(nil), "jsonpb.Mappy.U32boolyEntry")
 	proto.RegisterMapType((map[uint64]bool)(nil), "jsonpb.Mappy.U64boolyEntry")
-	proto.RegisterEnum("jsonpb.Numeral", Numeral_name, Numeral_value)
 }
 
 func init() { proto.RegisterFile("more_test_objects.proto", fileDescriptor_e6c135db3023e377) }

jsonpb/jsonpb_test_proto/test_objects.pb.go

@@ -1255,6 +1255,7 @@ var E_Extm = &proto.ExtensionDesc{
 }
 
 func init() {
+	proto.RegisterEnum("jsonpb.Widget_Color", Widget_Color_name, Widget_Color_value)
 	proto.RegisterType((*Simple)(nil), "jsonpb.Simple")
 	proto.RegisterType((*NonFinites)(nil), "jsonpb.NonFinites")
 	proto.RegisterType((*Repeats)(nil), "jsonpb.Repeats")
@@ -1264,6 +1265,7 @@ func init() {
 	proto.RegisterMapType((map[int64]string)(nil), "jsonpb.Maps.MInt64StrEntry")
 	proto.RegisterType((*MsgWithOneof)(nil), "jsonpb.MsgWithOneof")
 	proto.RegisterType((*Real)(nil), "jsonpb.Real")
+	proto.RegisterExtension(E_Complex_RealExtension)
 	proto.RegisterType((*Complex)(nil), "jsonpb.Complex")
 	proto.RegisterType((*KnownTypes)(nil), "jsonpb.KnownTypes")
 	proto.RegisterType((*MsgWithRequired)(nil), "jsonpb.MsgWithRequired")
@@ -1271,8 +1273,6 @@ func init() {
 	proto.RegisterMapType((map[string]*MsgWithRequired)(nil), "jsonpb.MsgWithIndirectRequired.MapFieldEntry")
 	proto.RegisterType((*MsgWithRequiredBytes)(nil), "jsonpb.MsgWithRequiredBytes")
 	proto.RegisterType((*MsgWithRequiredWKT)(nil), "jsonpb.MsgWithRequiredWKT")
-	proto.RegisterEnum("jsonpb.Widget_Color", Widget_Color_name, Widget_Color_value)
-	proto.RegisterExtension(E_Complex_RealExtension)
 	proto.RegisterExtension(E_Name)
 	proto.RegisterExtension(E_Extm)
 }

proto/proto3_proto/proto3.pb.go

@@ -542,6 +542,7 @@ func _TestUTF8_OneofSizer(msg proto.Message) (n int) {
 }
 
 func init() {
+	proto.RegisterEnum("proto3_proto.Message_Humour", Message_Humour_name, Message_Humour_value)
 	proto.RegisterType((*Message)(nil), "proto3_proto.Message")
 	proto.RegisterMapType((map[string]*test_proto.SubDefaults)(nil), "proto3_proto.Message.Proto2ValueEntry")
 	proto.RegisterMapType((map[string]string)(nil), "proto3_proto.Message.StringMapEntry")
@@ -555,7 +556,6 @@ func init() {
 	proto.RegisterType((*TestUTF8)(nil), "proto3_proto.TestUTF8")
 	proto.RegisterMapType((map[string]int64)(nil), "proto3_proto.TestUTF8.MapKeyEntry")
 	proto.RegisterMapType((map[int64]string)(nil), "proto3_proto.TestUTF8.MapValueEntry")
-	proto.RegisterEnum("proto3_proto.Message_Humour", Message_Humour_name, Message_Humour_value)
 }
 
 func init() { proto.RegisterFile("proto3_proto/proto3.proto", fileDescriptor_1c50d9b824d4ac38) }

proto/test_proto/test.pb.go

@@ -4930,6 +4930,12 @@ var E_X250 = &proto.ExtensionDesc{
 }
 
 func init() {
+	proto.RegisterEnum("test_proto.FOO", FOO_name, FOO_value)
+	proto.RegisterEnum("test_proto.GoTest_KIND", GoTest_KIND_name, GoTest_KIND_value)
+	proto.RegisterEnum("test_proto.MyMessage_Color", MyMessage_Color_name, MyMessage_Color_value)
+	proto.RegisterEnum("test_proto.DefaultsMessage_DefaultsEnum", DefaultsMessage_DefaultsEnum_name, DefaultsMessage_DefaultsEnum_value)
+	proto.RegisterEnum("test_proto.Defaults_Color", Defaults_Color_name, Defaults_Color_value)
+	proto.RegisterEnum("test_proto.RepeatedEnum_Color", RepeatedEnum_Color_name, RepeatedEnum_Color_value)
 	proto.RegisterType((*GoEnum)(nil), "test_proto.GoEnum")
 	proto.RegisterType((*GoTestField)(nil), "test_proto.GoTestField")
 	proto.RegisterType((*GoTest)(nil), "test_proto.GoTest")
@@ -4952,6 +4958,9 @@ func init() {
 	proto.RegisterType((*RequiredInnerMessage)(nil), "test_proto.RequiredInnerMessage")
 	proto.RegisterType((*MyMessage)(nil), "test_proto.MyMessage")
 	proto.RegisterType((*MyMessage_SomeGroup)(nil), "test_proto.MyMessage.SomeGroup")
+	proto.RegisterExtension(E_Ext_More)
+	proto.RegisterExtension(E_Ext_Text)
+	proto.RegisterExtension(E_Ext_Number)
 	proto.RegisterType((*Ext)(nil), "test_proto.Ext")
 	proto.RegisterMapType((map[int32]int32)(nil), "test_proto.Ext.MapFieldEntry")
 	proto.RegisterType((*ComplexExtension)(nil), "test_proto.ComplexExtension")
@@ -4981,15 +4990,6 @@ func init() {
 	proto.RegisterType((*TestUTF8)(nil), "test_proto.TestUTF8")
 	proto.RegisterMapType((map[string]int64)(nil), "test_proto.TestUTF8.MapKeyEntry")
 	proto.RegisterMapType((map[int64]string)(nil), "test_proto.TestUTF8.MapValueEntry")
-	proto.RegisterEnum("test_proto.FOO", FOO_name, FOO_value)
-	proto.RegisterEnum("test_proto.GoTest_KIND", GoTest_KIND_name, GoTest_KIND_value)
-	proto.RegisterEnum("test_proto.MyMessage_Color", MyMessage_Color_name, MyMessage_Color_value)
-	proto.RegisterEnum("test_proto.DefaultsMessage_DefaultsEnum", DefaultsMessage_DefaultsEnum_name, DefaultsMessage_DefaultsEnum_value)
-	proto.RegisterEnum("test_proto.Defaults_Color", Defaults_Color_name, Defaults_Color_value)
-	proto.RegisterEnum("test_proto.RepeatedEnum_Color", RepeatedEnum_Color_name, RepeatedEnum_Color_value)
-	proto.RegisterExtension(E_Ext_More)
-	proto.RegisterExtension(E_Ext_Text)
-	proto.RegisterExtension(E_Ext_Number)
 	proto.RegisterExtension(E_Greeting)
 	proto.RegisterExtension(E_Complex)
 	proto.RegisterExtension(E_RComplex)

protoc-gen-go/descriptor/descriptor.pb.go

@@ -2661,6 +2661,12 @@ func (m *GeneratedCodeInfo_Annotation) GetEnd() int32 {
 }
 
 func init() {
+	proto.RegisterEnum("google.protobuf.FieldDescriptorProto_Type", FieldDescriptorProto_Type_name, FieldDescriptorProto_Type_value)
+	proto.RegisterEnum("google.protobuf.FieldDescriptorProto_Label", FieldDescriptorProto_Label_name, FieldDescriptorProto_Label_value)
+	proto.RegisterEnum("google.protobuf.FileOptions_OptimizeMode", FileOptions_OptimizeMode_name, FileOptions_OptimizeMode_value)
+	proto.RegisterEnum("google.protobuf.FieldOptions_CType", FieldOptions_CType_name, FieldOptions_CType_value)
+	proto.RegisterEnum("google.protobuf.FieldOptions_JSType", FieldOptions_JSType_name, FieldOptions_JSType_value)
+	proto.RegisterEnum("google.protobuf.MethodOptions_IdempotencyLevel", MethodOptions_IdempotencyLevel_name, MethodOptions_IdempotencyLevel_value)
 	proto.RegisterType((*FileDescriptorSet)(nil), "google.protobuf.FileDescriptorSet")
 	proto.RegisterType((*FileDescriptorProto)(nil), "google.protobuf.FileDescriptorProto")
 	proto.RegisterType((*DescriptorProto)(nil), "google.protobuf.DescriptorProto")
@@ -2688,12 +2694,6 @@ func init() {
 	proto.RegisterType((*SourceCodeInfo_Location)(nil), "google.protobuf.SourceCodeInfo.Location")
 	proto.RegisterType((*GeneratedCodeInfo)(nil), "google.protobuf.GeneratedCodeInfo")
 	proto.RegisterType((*GeneratedCodeInfo_Annotation)(nil), "google.protobuf.GeneratedCodeInfo.Annotation")
-	proto.RegisterEnum("google.protobuf.FieldDescriptorProto_Type", FieldDescriptorProto_Type_name, FieldDescriptorProto_Type_value)
-	proto.RegisterEnum("google.protobuf.FieldDescriptorProto_Label", FieldDescriptorProto_Label_name, FieldDescriptorProto_Label_value)
-	proto.RegisterEnum("google.protobuf.FileOptions_OptimizeMode", FileOptions_OptimizeMode_name, FileOptions_OptimizeMode_value)
-	proto.RegisterEnum("google.protobuf.FieldOptions_CType", FieldOptions_CType_name, FieldOptions_CType_value)
-	proto.RegisterEnum("google.protobuf.FieldOptions_JSType", FieldOptions_JSType_name, FieldOptions_JSType_value)
-	proto.RegisterEnum("google.protobuf.MethodOptions_IdempotencyLevel", MethodOptions_IdempotencyLevel_name, MethodOptions_IdempotencyLevel_value)
 }
 
 func init() { proto.RegisterFile("google/protobuf/descriptor.proto", fileDescriptor_e5baabe45344a177) }

protoc-gen-go/generator/generator.go

@@ -1423,6 +1423,8 @@ func (g *Generator) generateEnum(enum *EnumDescriptor) {
 		g.P("func (", ccTypeName, `) XXX_WellKnownType() string { return "`, enum.GetName(), `" }`)
 		g.P()
 	}
+
+	g.generateEnumRegistration(enum)
 }
 
 // The tag is a string like "varint,2,opt,name=fieldname,def=7" that
@@ -2797,6 +2799,7 @@ func (g *Generator) generateExtension(ext *ExtensionDescriptor) {
 	g.P("}")
 	g.P()
 
+	g.addInitf("%s.RegisterExtension(%s)", g.Pkg["proto"], ext.DescName())
 	if mset {
 		// Generate a bit more code to register with message_set.go.
 		g.addInitf("%s.RegisterMessageSetType((%s)(nil), %d, %q)", g.Pkg["proto"], fieldType, *field.Number, extName)
@@ -2806,17 +2809,6 @@ func (g *Generator) generateExtension(ext *ExtensionDescriptor) {
 }
 
 func (g *Generator) generateInitFunction() {
-	for _, enum := range g.file.enum {
-		g.generateEnumRegistration(enum)
-	}
-	for _, d := range g.file.desc {
-		for _, ext := range d.ext {
-			g.generateExtensionRegistration(ext)
-		}
-	}
-	for _, ext := range g.file.ext {
-		g.generateExtensionRegistration(ext)
-	}
 	if len(g.init) == 0 {
 		return
 	}
@@ -2880,10 +2872,6 @@ func (g *Generator) generateEnumRegistration(enum *EnumDescriptor) {
 	g.addInitf("%s.RegisterEnum(%q, %[3]s_name, %[3]s_value)", g.Pkg["proto"], pkg+ccTypeName, ccTypeName)
 }
 
-func (g *Generator) generateExtensionRegistration(ext *ExtensionDescriptor) {
-	g.addInitf("%s.RegisterExtension(%s)", g.Pkg["proto"], ext.DescName())
-}
-
 // And now lots of helper functions.
 
 // Is c an ASCII lower-case letter?

protoc-gen-go/testdata/deprecated/deprecated.pb.go

@@ -127,9 +127,9 @@ func (m *DeprecatedResponse) GetDeprecatedField() DeprecatedEnum {
 }
 
 func init() {
+	proto.RegisterEnum("deprecated.DeprecatedEnum", DeprecatedEnum_name, DeprecatedEnum_value)
 	proto.RegisterType((*DeprecatedRequest)(nil), "deprecated.DeprecatedRequest")
 	proto.RegisterType((*DeprecatedResponse)(nil), "deprecated.DeprecatedResponse")
-	proto.RegisterEnum("deprecated.DeprecatedEnum", DeprecatedEnum_name, DeprecatedEnum_value)
 }
 
 // Reference imports to suppress errors if they are not otherwise used.

protoc-gen-go/testdata/extension_user/extension_user.pb.go

@@ -352,16 +352,16 @@ var E_Detail = &proto.ExtensionDesc{
 
 func init() {
 	proto.RegisterType((*UserMessage)(nil), "extension_user.UserMessage")
+	proto.RegisterExtension(E_LoudMessage_Volume)
 	proto.RegisterType((*LoudMessage)(nil), "extension_user.LoudMessage")
+	proto.RegisterExtension(E_LoginMessage_UserMessage)
 	proto.RegisterType((*LoginMessage)(nil), "extension_user.LoginMessage")
 	proto.RegisterType((*Detail)(nil), "extension_user.Detail")
+	proto.RegisterExtension(E_Announcement_LoudExt)
 	proto.RegisterType((*Announcement)(nil), "extension_user.Announcement")
+	proto.RegisterExtension(E_OldStyleParcel_MessageSetExtension)
 	proto.RegisterMessageSetType((*OldStyleParcel)(nil), 2001, "extension_user.OldStyleParcel")
 	proto.RegisterType((*OldStyleParcel)(nil), "extension_user.OldStyleParcel")
-	proto.RegisterExtension(E_LoudMessage_Volume)
-	proto.RegisterExtension(E_LoginMessage_UserMessage)
-	proto.RegisterExtension(E_Announcement_LoudExt)
-	proto.RegisterExtension(E_OldStyleParcel_MessageSetExtension)
 	proto.RegisterExtension(E_UserMessage)
 	proto.RegisterExtension(E_ExtraMessage)
 	proto.RegisterExtension(E_Width)

protoc-gen-go/testdata/import_public/sub/a.pb.go

@@ -368,11 +368,11 @@ func _M_Submessage_OneofSizer(msg proto.Message) (n int) {
 }
 
 func init() {
-	proto.RegisterType((*M)(nil), "goproto.test.import_public.sub.M")
-	proto.RegisterType((*M_Submessage)(nil), "goproto.test.import_public.sub.M.Submessage")
 	proto.RegisterEnum("goproto.test.import_public.sub.E", E_name, E_value)
 	proto.RegisterEnum("goproto.test.import_public.sub.M_Subenum", M_Subenum_name, M_Subenum_value)
 	proto.RegisterEnum("goproto.test.import_public.sub.M_Submessage_Submessage_Subenum", M_Submessage_Submessage_Subenum_name, M_Submessage_Submessage_Subenum_value)
+	proto.RegisterType((*M)(nil), "goproto.test.import_public.sub.M")
+	proto.RegisterType((*M_Submessage)(nil), "goproto.test.import_public.sub.M.Submessage")
 }
 
 func init() { proto.RegisterFile("import_public/sub/a.proto", fileDescriptor_382f7805394b5c4e) }

protoc-gen-go/testdata/imports/test_a_1/m1.pb.go

@@ -113,9 +113,9 @@ func (m *M1_1) GetM1() *M1 {
 }
 
 func init() {
+	proto.RegisterEnum("test.a.E1", E1_name, E1_value)
 	proto.RegisterType((*M1)(nil), "test.a.M1")
 	proto.RegisterType((*M1_1)(nil), "test.a.M1_1")
-	proto.RegisterEnum("test.a.E1", E1_name, E1_value)
 }
 
 func init() { proto.RegisterFile("imports/test_a_1/m1.proto", fileDescriptor_c1091de3fa870a14) }

protoc-gen-go/testdata/multi/multi2.pb.go

@@ -111,8 +111,8 @@ func (m *Multi2) GetColor() Multi2_Color {
 }
 
 func init() {
-	proto.RegisterType((*Multi2)(nil), "multitest.Multi2")
 	proto.RegisterEnum("multitest.Multi2_Color", Multi2_Color_name, Multi2_Color_value)
+	proto.RegisterType((*Multi2)(nil), "multitest.Multi2")
 }
 
 func init() { proto.RegisterFile("multi/multi2.proto", fileDescriptor_a2aebe588a0b2853) }

protoc-gen-go/testdata/multi/multi3.pb.go

@@ -100,8 +100,8 @@ func (m *Multi3) GetHatType() Multi3_HatType {
 }
 
 func init() {
-	proto.RegisterType((*Multi3)(nil), "multitest.Multi3")
 	proto.RegisterEnum("multitest.Multi3_HatType", Multi3_HatType_name, Multi3_HatType_value)
+	proto.RegisterType((*Multi3)(nil), "multitest.Multi3")
 }
 
 func init() { proto.RegisterFile("multi/multi3.proto", fileDescriptor_580398fc0bbeeaa7) }

protoc-gen-go/testdata/my_test/test.pb.go

@@ -1123,6 +1123,10 @@ var E_Donut = &proto.ExtensionDesc{
 }
 
 func init() {
+	proto.RegisterEnum("my.test.HatType", HatType_name, HatType_value)
+	proto.RegisterEnum("my.test.Days", Days_name, Days_value)
+	proto.RegisterEnum("my.test.Request_Color", Request_Color_name, Request_Color_value)
+	proto.RegisterEnum("my.test.Reply_Entry_Game", Reply_Entry_Game_name, Reply_Entry_Game_value)
 	proto.RegisterType((*Request)(nil), "my.test.Request")
 	proto.RegisterMapType((map[int64]*Reply)(nil), "my.test.Request.MsgMappingEntry")
 	proto.RegisterMapType((map[int32]string)(nil), "my.test.Request.NameMappingEntry")
@@ -1130,19 +1134,15 @@ func init() {
 	proto.RegisterType((*Reply)(nil), "my.test.Reply")
 	proto.RegisterType((*Reply_Entry)(nil), "my.test.Reply.Entry")
 	proto.RegisterType((*OtherBase)(nil), "my.test.OtherBase")
+	proto.RegisterExtension(E_ReplyExtensions_Time)
+	proto.RegisterExtension(E_ReplyExtensions_Carrot)
+	proto.RegisterExtension(E_ReplyExtensions_Donut)
 	proto.RegisterType((*ReplyExtensions)(nil), "my.test.ReplyExtensions")
 	proto.RegisterType((*OtherReplyExtensions)(nil), "my.test.OtherReplyExtensions")
 	proto.RegisterType((*OldReply)(nil), "my.test.OldReply")
 	proto.RegisterType((*Communique)(nil), "my.test.Communique")
 	proto.RegisterType((*Communique_SomeGroup)(nil), "my.test.Communique.SomeGroup")
 	proto.RegisterType((*Communique_Delta)(nil), "my.test.Communique.Delta")
-	proto.RegisterEnum("my.test.HatType", HatType_name, HatType_value)
-	proto.RegisterEnum("my.test.Days", Days_name, Days_value)
-	proto.RegisterEnum("my.test.Request_Color", Request_Color_name, Request_Color_value)
-	proto.RegisterEnum("my.test.Reply_Entry_Game", Reply_Entry_Game_name, Reply_Entry_Game_value)
-	proto.RegisterExtension(E_ReplyExtensions_Time)
-	proto.RegisterExtension(E_ReplyExtensions_Carrot)
-	proto.RegisterExtension(E_ReplyExtensions_Donut)
 	proto.RegisterExtension(E_Tag)
 	proto.RegisterExtension(E_Donut)
 }

protoc-gen-go/testdata/proto3/proto3.pb.go

@@ -170,9 +170,9 @@ func (m *Book) GetRawData() []byte {
 }
 
 func init() {
+	proto.RegisterEnum("proto3.Request_Flavour", Request_Flavour_name, Request_Flavour_value)
 	proto.RegisterType((*Request)(nil), "proto3.Request")
 	proto.RegisterType((*Book)(nil), "proto3.Book")
-	proto.RegisterEnum("proto3.Request_Flavour", Request_Flavour_name, Request_Flavour_value)
 }
 
 func init() { proto.RegisterFile("proto3/proto3.proto", fileDescriptor_ab04eb4084a521db) }

ptypes/struct/struct.pb.go

@@ -418,11 +418,11 @@ func (m *ListValue) GetValues() []*Value {
 }
 
 func init() {
+	proto.RegisterEnum("google.protobuf.NullValue", NullValue_name, NullValue_value)
 	proto.RegisterType((*Struct)(nil), "google.protobuf.Struct")
 	proto.RegisterMapType((map[string]*Value)(nil), "google.protobuf.Struct.FieldsEntry")
 	proto.RegisterType((*Value)(nil), "google.protobuf.Value")
 	proto.RegisterType((*ListValue)(nil), "google.protobuf.ListValue")
-	proto.RegisterEnum("google.protobuf.NullValue", NullValue_name, NullValue_value)
 }
 
 func init() { proto.RegisterFile("google/protobuf/struct.proto", fileDescriptor_df322afd6c9fb402) }