Add -embed flag into mockgen

mockgen/internal/tests/embed/input.go

@@ -0,0 +1,17 @@
+package embed
+
+//go:generate mockgen -embed -package embed -destination mock.go . Hoge
+//go:generate mockgen -embed -destination mock/mock.go . Hoge
+
+type Hoge interface {
+	Fuga() error
+	mustImplementedFunction()
+}
+
+type HogeImpl struct {
+	s string
+}
+
+func (h *HogeImpl) Fuga() error {
+	return nil
+}

mockgen/internal/tests/embed/mock/mock_test.go

@@ -0,0 +1,19 @@
+package mock_embed_test
+
+import (
+	reflect "reflect"
+	"testing"
+
+	"go.uber.org/mock/gomock"
+	"go.uber.org/mock/mockgen/internal/tests/embed"
+	mock_embed "go.uber.org/mock/mockgen/internal/tests/embed/mock"
+)
+
+func TestEmbed(t *testing.T) {
+	hoge := mock_embed.NewMockHoge(gomock.NewController(t))
+	et := reflect.TypeOf((*embed.Hoge)(nil)).Elem()
+	ht := reflect.TypeOf(hoge)
+	if !ht.Implements(et) {
+		t.Errorf("source interface has been not implemented")
+	}
+}

mockgen/internal/tests/embed/mock_test.go

@@ -0,0 +1,19 @@
+// This test is for when mock is same package as the source.
+package embed_test
+
+import (
+	reflect "reflect"
+	"testing"
+
+	"go.uber.org/mock/gomock"
+	"go.uber.org/mock/mockgen/internal/tests/embed"
+)
+
+func TestEmbed(t *testing.T) {
+	hoge := embed.NewMockHoge(gomock.NewController(t))
+	et := reflect.TypeOf((*embed.Hoge)(nil)).Elem()
+	ht := reflect.TypeOf(hoge)
+	if !ht.Implements(et) {
+		t.Errorf("source interface has been not implemented")
+	}
+}

mockgen/mockgen.go

@@ -64,6 +64,7 @@ var (
 	writeSourceComment     = flag.Bool("write_source_comment", true, "Writes original file (source mode) or interface names (package mode) comment if true.")
 	writeGenerateDirective = flag.Bool("write_generate_directive", false, "Add //go:generate directive to regenerate the mock")
 	copyrightFile          = flag.String("copyright_file", "", "Copyright file used to add copyright header")
+	embed                  = flag.Bool("embed", false, "Embed source interface into generated mock structure")
 	buildConstraint        = flag.String("build_constraint", "", "If non-empty, added as //go:build <constraint>")
 	typed                  = flag.Bool("typed", false, "Generate Type-safe 'Return', 'Do', 'DoAndReturn' function")
 	imports                = flag.String("imports", "", "(source mode) Comma-separated name=path pairs of explicit imports to use.")
@@ -411,6 +412,9 @@ func (g *generator) Generate(pkg *model.Package, outputPkgName string, outputPac
 		g.packageMap[pth] = pkgName
 		localNames[pkgName] = true
 	}
+	if *embed && pkg.Name != *packageOut {
+		g.packageMap[g.srcPackage] = pkg.Name
+	}
 
 	// Ensure there is an empty line between “generated by” block and
 	// package documentation comments to follow the recommendations:
@@ -442,7 +446,7 @@ func (g *generator) Generate(pkg *model.Package, outputPkgName string, outputPac
 	}
 
 	for _, intf := range pkg.Interfaces {
-		if err := g.GenerateMockInterface(intf, outputPackagePath); err != nil {
+		if err := g.GenerateMockInterface(pkg.Name, intf, outputPackagePath); err != nil {
 			return err
 		}
 	}
@@ -484,14 +488,21 @@ func (g *generator) formattedTypeParams(it *model.Interface, pkgOverride string)
 	return long.String(), short.String()
 }
 
-func (g *generator) GenerateMockInterface(intf *model.Interface, outputPackagePath string) error {
+func (g *generator) GenerateMockInterface(pkgName string, intf *model.Interface, outputPackagePath string) error {
 	mockType := g.mockName(intf.Name)
 	longTp, shortTp := g.formattedTypeParams(intf, outputPackagePath)
 
 	g.p("")
 	g.p("// %v is a mock of %v interface.", mockType, intf.Name)
 	g.p("type %v%v struct {", mockType, longTp)
 	g.in()
+	if *embed {
+		if pkgName != *packageOut {
+			g.p("%v.%v", pkgName, intf.Name)
+		} else {
+			g.p("%v", intf.Name)
+		}
+	}
 	g.p("ctrl     *gomock.Controller")
 	g.p("recorder *%vMockRecorder%v", mockType, shortTp)
 	g.p("isgomock struct{}")