2 files changed, 76 insertions, 2 deletions

diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index 530e8521dc..4d17c279bd 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -358,7 +358,7 @@ func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler,
 		if v.IsNil() {
 			v.Set(reflect.New(v.Type().Elem()))
 		}
-		if v.Type().NumMethod() > 0 {
+		if v.Type().NumMethod() > 0 && !decodingNull {
 			if u, ok := v.Interface().(Unmarshaler); ok {
 				return u, nil, reflect.Value{}
 			}
diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index 8aa158f08c..8c449d4784 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -1322,7 +1322,48 @@ func (t *Time3339) UnmarshalJSON(b []byte) error {
 	return nil
 }
 
-func TestUnmarshalJSONLiteralError(t *testing.T) {
+// A Time-like type supporting the json Unmarshal interface
+type AJson struct {
+	T int
+}
+
+func (t *AJson) UnmarshalJSON(b []byte) error {
+	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
+		return fmt.Errorf("types: failed to unmarshal non-string value %q", b)
+	}
+	if _, err := fmt.Sscanf(string(b[1:len(b)-1]), "%d", &t.T); err != nil {
+		return err
+	}
+	return nil
+}
+
+// A Time-like type supporting the text Unmarshal interface
+type AText struct {
+	T int
+}
+
+func (t *AText) UnmarshalText(b []byte) error {
+	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
+		return fmt.Errorf("types: failed to unmarshal non-string value %q", b)
+	}
+	if _, err := fmt.Sscanf(string(b[1:len(b)-1]), "%d", &t.T); err != nil {
+		return err
+	}
+	return nil
+}
+
+// This type mixes pointers and structures, supporting json or text Unmarshal interfaces
+type STime struct {
+	X  int
+	J1 AJson
+	J2 *AJson
+	J3 **AJson
+	T1 AText
+	T2 *AText
+	T3 **AText
+}
+
+func TestUnmarshalJSONLiteralError1(t *testing.T) {
 	var t3 Time3339
 	err := Unmarshal([]byte(`"0000-00-00T00:00:00Z"`), &t3)
 	if err == nil {
@@ -1331,6 +1372,39 @@ func TestUnmarshalJSONLiteralError(t *testing.T) {
 	if !strings.Contains(err.Error(), "range") {
 		t.Errorf("got err = %v; want out of range error", err)
 	}
+
+	out := time.Now()
+	want := out
+	err = Unmarshal([]byte(`null`), &out)
+	if err != nil {
+		t.Fatalf("got err = %v; no error was expected", err)
+	}
+	if out != want {
+		t.Fatalf("got %q, want %q", out, want)
+	}
+}
+
+func TestUnmarshalJSONLiteralError2(t *testing.T) {
+	out := STime{
+		X:  1,
+		J1: AJson{2},
+		J2: &AJson{3},
+		J3: new(*AJson),
+		T1: AText{5},
+		T2: &AText{6},
+		T3: new(*AText),
+	}
+	want := out
+	want.J2 = nil
+	want.T2 = nil
+	// Keep the spaces as they are in the following line
+	err := Unmarshal([]byte(`{"X":1,"J1":null,"J2":null,"J3": null,"T1":null ,"T2": null , "T3":null}`), &out)
+	if err != nil {
+		t.Fatalf("got err = %v; no error was expected", err)
+	}
+	if out != want {
+		t.Fatalf("got %v, want %v", out, want)
+	}
 }
 
 // Test that extra object elements in an array do not result in a