unmarshal does not return nil object when value is nil

Signed-off-by: Iceber Gu <wei.cai-nat@daocloud.io>

types.go

@@ -194,10 +194,6 @@ func UnmarshalToByTypeURL(typeURL string, value []byte, out interface{}) error {
 }
 
 func unmarshal(typeURL string, value []byte, v interface{}) (interface{}, error) {
-	if value == nil {
-		return nil, nil
-	}
-
 	t, err := getTypeByUrl(typeURL)
 	if err != nil {
 		return nil, err
@@ -216,6 +212,10 @@ func unmarshal(typeURL string, value []byte, v interface{}) (interface{}, error)
 		}
 	}
 
+	if value == nil {
+		return v, err
+	}
+
 	if t.isProto {
 		switch t := v.(type) {
 		case proto.Message:

types_test.go

@@ -195,24 +195,22 @@ func TestRegisterDiffUrls(t *testing.T) {
 	Register(&test{}, "test", "two")
 }
 
-func TestUnmarshalNil(t *testing.T) {
-	var pba *anypb.Any // This is nil.
-	var a Any = pba    // This is typed nil.
+func TestUnmarshalNilValue(t *testing.T) {
+	clear()
+	Register(&test{}, "test")
 
-	if pba != nil {
-		t.Fatal("pbany must be nil")
-	}
-	if a == nil {
-		t.Fatal("nilany must not be nil")
+	var a Any = &anyType{
+		typeURL: "test",
+		value:   nil,
 	}
 
 	actual, err := UnmarshalAny(a)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	if actual != nil {
-		t.Fatalf("expected nil, got %v", actual)
+	if _, ok := actual.(*test); !ok {
+		t.Fatalf("expected *test, got %v", actual)
 	}
 }