fix: fixed a problem that MarshalIndent does not work when UnorderedMap is specified (#435)

Author: orisano

encode_test.go

@@ -2630,6 +2630,22 @@ func TestCustomMarshalForMapKey(t *testing.T) {
 	assertEq(t, "custom map key", string(expected), string(got))
 }
 
+func TestIssue417(t *testing.T) {
+	x := map[string]string{
+		"b": "b",
+		"a": "a",
+	}
+	b, err := json.MarshalIndentWithOption(x, "", " ", json.UnorderedMap())
+	assertErr(t, err)
+
+	var y map[string]string
+	err = json.Unmarshal(b, &y)
+	assertErr(t, err)
+
+	assertEq(t, "key b", "b", y["b"])
+	assertEq(t, "key a", "a", y["a"])
+}
+
 func TestIssue426(t *testing.T) {
 	type I interface {
 		Foo()

internal/encoder/vm_color_indent/util.go

@@ -189,7 +189,7 @@ func appendNullComma(ctx *encoder.RuntimeContext, b []byte) []byte {
 }
 
 func appendColon(_ *encoder.RuntimeContext, b []byte) []byte {
-	return append(b, ':', ' ')
+	return append(b[:len(b)-2], ':', ' ')
 }
 
 func appendMapKeyValue(ctx *encoder.RuntimeContext, code *encoder.Opcode, b, key, value []byte) []byte {
@@ -229,8 +229,9 @@ func appendEmptyObject(_ *encoder.RuntimeContext, b []byte) []byte {
 
 func appendObjectEnd(ctx *encoder.RuntimeContext, code *encoder.Opcode, b []byte) []byte {
 	last := len(b) - 1
-	b[last] = '\n'
-	b = appendIndent(ctx, b, code.Indent-1)
+	// replace comma to newline
+	b[last-1] = '\n'
+	b = appendIndent(ctx, b[:last], code.Indent)
 	return append(b, '}', ',', '\n')
 }
 

internal/encoder/vm_indent/util.go

@@ -133,7 +133,7 @@ func appendNullComma(_ *encoder.RuntimeContext, b []byte) []byte {
 }
 
 func appendColon(_ *encoder.RuntimeContext, b []byte) []byte {
-	return append(b, ':', ' ')
+	return append(b[:len(b)-2], ':', ' ')
 }
 
 func appendMapKeyValue(ctx *encoder.RuntimeContext, code *encoder.Opcode, b, key, value []byte) []byte {
@@ -173,8 +173,9 @@ func appendEmptyObject(_ *encoder.RuntimeContext, b []byte) []byte {
 
 func appendObjectEnd(ctx *encoder.RuntimeContext, code *encoder.Opcode, b []byte) []byte {
 	last := len(b) - 1
-	b[last] = '\n'
-	b = appendIndent(ctx, b, code.Indent-1)
+	// replace comma to newline
+	b[last-1] = '\n'
+	b = appendIndent(ctx, b[:last], code.Indent)
 	return append(b, '}', ',', '\n')
 }