Merge pull request #36 from ipfs/fix/maybeerror-nil-value

MaybeError: add support for untyped parsing

maybeerror_test.go

@@ -31,7 +31,7 @@ type anyTestCase struct {
 
 func TestMaybeError(t *testing.T) {
 	testcases := []anyTestCase{
-		anyTestCase{
+		{
 			Value: &Foo{},
 			JSON:  `{"Bar":23}{"Bar":42}{"Message":"some error", "Type": "error"}`,
 			Decoded: []ValueError{
@@ -40,7 +40,7 @@ func TestMaybeError(t *testing.T) {
 				ValueError{Error: nil, Value: cmdkit.Error{Message: "some error", Code: 0}},
 			},
 		},
-		anyTestCase{
+		{
 			Value: Foo{},
 			JSON:  `{"Bar":23}{"Bar":42}{"Message":"some error", "Type": "error"}`,
 			Decoded: []ValueError{
@@ -49,7 +49,7 @@ func TestMaybeError(t *testing.T) {
 				ValueError{Error: nil, Value: cmdkit.Error{Message: "some error", Code: 0}},
 			},
 		},
-		anyTestCase{
+		{
 			Value: &Bar{},
 			JSON:  `{"Foo":""}{"Foo":"Qmabc"}{"Message":"some error", "Type": "error"}`,
 			Decoded: []ValueError{
@@ -58,7 +58,7 @@ func TestMaybeError(t *testing.T) {
 				ValueError{Error: nil, Value: cmdkit.Error{Message: "some error", Code: 0}},
 			},
 		},
-		anyTestCase{
+		{
 			Value: Bar{},
 			JSON:  `{"Foo":""}{"Foo":"Qmabc"}{"Message":"some error", "Type": "error"}`,
 			Decoded: []ValueError{
@@ -67,10 +67,18 @@ func TestMaybeError(t *testing.T) {
 				ValueError{Error: nil, Value: cmdkit.Error{Message: "some error", Code: 0}},
 			},
 		},
+		{
+			JSON: `{"Foo":"bar", "i": 4}"some string"5{"Message":"some error", "Type": "error"}`,
+			Decoded: []ValueError{
+				ValueError{Error: nil, Value: map[string]interface{}{"Foo": "bar", "i": 4.0}},
+				ValueError{Error: nil, Value: "some string"},
+				ValueError{Error: nil, Value: 5.0},
+				ValueError{Error: nil, Value: cmdkit.Error{Message: "some error", Code: 0}},
+			},
+		},
 	}
 
 	for _, tc := range testcases {
-		m := &MaybeError{Value: tc.Value}
 
 		r := strings.NewReader(tc.JSON)
 		d := json.NewDecoder(r)
@@ -78,31 +86,22 @@ func TestMaybeError(t *testing.T) {
 		var err error
 
 		for _, dec := range tc.Decoded {
+			m := &MaybeError{Value: tc.Value}
+
 			err = d.Decode(m)
 			if err != dec.Error {
 				t.Fatalf("error is %v, expected %v", err, dec.Error)
 			}
 
 			rx := m.Get()
-			rxIsPtr := reflect.TypeOf(rx).Kind() == reflect.Ptr
-
 			ex := dec.Value
-			exIsPtr := reflect.TypeOf(ex).Kind() == reflect.Ptr
-
-			if rxIsPtr != exIsPtr {
-				t.Fatalf("value is %#v, expected %#v", m.Get(), dec.Value)
-			}
 
-			if rxIsPtr {
-				rx = reflect.ValueOf(rx).Elem().Interface()
-				ex = reflect.ValueOf(ex).Elem().Interface()
-			}
-
-			if rx != ex {
-				t.Fatalf("value is %#v, expected %#v", m.Get(), dec.Value)
+			if !reflect.DeepEqual(ex, rx) {
+				t.Errorf("value is %#v(%T), expected %#v(%T)", rx, rx, ex, ex)
 			}
 		}
 
+		m := &MaybeError{Value: tc.Value}
 		err = d.Decode(m)
 		if err != io.EOF {
 			t.Fatal("data left in decoder:", m.Get())

writer.go

@@ -188,11 +188,18 @@ func (m *MaybeError) UnmarshalJSON(data []byte) error {
 		return nil
 	}
 
-	// make sure we are working with a pointer here
-	v := reflect.ValueOf(m.Value)
-	if v.Kind() != reflect.Ptr {
-		m.Value = reflect.New(v.Type()).Interface()
+	if m.Value != nil {
+		// make sure we are working with a pointer here
+		v := reflect.ValueOf(m.Value)
+		if v.Kind() != reflect.Ptr {
+			m.Value = reflect.New(v.Type()).Interface()
+		}
+
+		err = json.Unmarshal(data, m.Value)
+	} else {
+		// let the json decoder decode into whatever it finds appropriate
+		err = json.Unmarshal(data, &m.Value)
 	}
 
-	return json.Unmarshal(data, m.Value)
+	return err
 }