Merge pull request #307 from wenerme/unwrap

unwrap type to detect nil ptr prevent panic fix #306

msgpack_test.go

@@ -459,3 +459,19 @@ func ExampleMarshal_ignore_simple_zero_structs_when_tagged_with_omitempty() {
 	// Output: msgpack_test.T{I:msgpack_test.NullInt{Valid:false, Int:0}, J:msgpack_test.NullInt{Valid:true, Int:0}, S:msgpack_test.Secretive{Visible:false, hidden:false}}
 	// msgpack_test.T{I:msgpack_test.NullInt{Valid:true, Int:42}, J:msgpack_test.NullInt{Valid:true, Int:0}, S:msgpack_test.Secretive{Visible:false, hidden:false}}
 }
+
+type Value interface{}
+type Wrapper struct {
+	Value Value `msgpack:"v,omitempty"`
+}
+
+func TestEncodeWrappedValue(t *testing.T) {
+	var v Value
+	v = (*time.Time)(nil)
+	c := &Wrapper{
+		Value: v,
+	}
+	var buf bytes.Buffer
+	require.Nil(t, msgpack.NewEncoder(&buf).Encode(v))
+	require.Nil(t, msgpack.NewEncoder(&buf).Encode(c))
+}

types.go

@@ -318,6 +318,13 @@ type isZeroer interface {
 }
 
 func isEmptyValue(v reflect.Value) bool {
+	// unwrap to detect nil ptr
+	for v.Kind() == reflect.Interface || v.Kind() == reflect.Ptr {
+		if v.IsNil() {
+			return true
+		}
+		v = v.Elem()
+	}
 	if z, ok := v.Interface().(isZeroer); ok {
 		return nilable(v.Kind()) && v.IsNil() || z.IsZero()
 	}
@@ -332,8 +339,6 @@ func isEmptyValue(v reflect.Value) bool {
 		return v.Uint() == 0
 	case reflect.Float32, reflect.Float64:
 		return v.Float() == 0
-	case reflect.Interface, reflect.Ptr:
-		return v.IsNil()
 	}
 	return false
 }