Make mockgen mock dependencies in vendor dir

mockgen/model/model.go

@@ -23,6 +23,9 @@ import (
 	"strings"
 )
 
+// pkgPath is the importable path for package model
+const pkgPath = "github.com/golang/mock/mockgen/model"
+
 // Package is a Go package. It may be a subset.
 type Package struct {
 	Name       string
@@ -131,7 +134,15 @@ func init() {
 	gob.Register(&MapType{})
 	gob.Register(&NamedType{})
 	gob.Register(&PointerType{})
-	gob.Register(PredeclaredType(""))
+
+	// Call gob.RegisterName to make sure it has the consistent name registered
+	// for both gob decoder and encoder.
+	//
+	// For a non-pointer type, gob.Register will try to get package full path by
+	// calling rt.PkgPath() for a name to register. If your project has vendor
+	// directory, it is possible that PkgPath will get a path like this:
+	//     ../../../vendor/github.com/golang/mock/mockgen/model
+	gob.RegisterName(pkgPath+".PredeclaredType", PredeclaredType(""))
 }
 
 // ArrayType is an array or slice type.

mockgen/reflect.go

@@ -42,8 +42,11 @@ func Reflect(importPath string, symbols []string) (*model.Package, error) {
 
 	progPath := *execOnly
 	if *execOnly == "" {
+		pwd, _ := os.Getwd()
 		// We use TempDir instead of TempFile so we can control the filename.
-		tmpDir, err := ioutil.TempDir("", "gomock_reflect_")
+		// Try to place the TempDir under pwd, so that if there is some package in
+		// vendor directory, 'go build' can also load/mock it.
+		tmpDir, err := ioutil.TempDir(pwd, "gomock_reflect_")
 		if err != nil {
 			return nil, err
 		}

mockgen/tests/vendor_pkg/README.md

@@ -0,0 +1 @@
+Test for [Issue#4](https://github.com/golang/mock/issues/4).

mockgen/tests/vendor_pkg/doc.go

@@ -0,0 +1,3 @@
+package vendor_pkg
+
+//go:generate mockgen a Ifc

mockgen/tests/vendor_pkg/vendor/a/a.go

@@ -0,0 +1,10 @@
+package a
+
+type Ifc interface {
+	A(string) string
+	B(int) int
+	C(chan int) chan int
+	D(interface{})
+	E(map[string]interface{})
+	F([]float64)
+}