Support vendor directory as $GOPATH/src/vendor

context.go

@@ -124,6 +124,11 @@ func (c *Ctx) LoadProject(path string) (*Project, error) {
 //
 // The second returned string indicates which GOPATH value was used.
 func (c *Ctx) SplitAbsoluteProjectRoot(path string) (string, error) {
+	// allow vendor directory to be directly under GOPATH/src
+	if filepath.Join(c.GOPATH, "src") == path {
+		return ".", nil
+	}
+
 	srcprefix := filepath.Join(c.GOPATH, "src") + string(filepath.Separator)
 	if filepath.HasPrefix(path, srcprefix) {
 		// filepath.ToSlash because we're dealing with an import path now,

context_test.go

@@ -57,6 +57,13 @@ func TestSplitAbsoluteProjectRoot(t *testing.T) {
 		}
 	}
 
+	// test when the full path corresponds to $GOPATH/src
+	if got, err := depCtx.SplitAbsoluteProjectRoot(filepath.Join(depCtx.GOPATH, "src")); err != nil {
+		t.Fatal(err)
+	} else if got != "." {
+		t.Fatalf("expected ., got %s", got)
+	}
+
 	// test where it should return error
 	got, err := depCtx.SplitAbsoluteProjectRoot("tra/la/la/la")
 	if err == nil {