Merge pull request #198 from goccy/feature/fix-decoding-of-slice

Fix decoding of slice with type implemented UnmarshalJSON

decode_slice.go

@@ -9,6 +9,7 @@ import (
 type sliceDecoder struct {
 	elemType                *rtype
 	isElemPointerType       bool
+	isElemUnmarshalJSONType bool
 	valueDecoder            decoder
 	size                    uintptr
 	arrayPool               sync.Pool
@@ -34,6 +35,7 @@ func newSliceDecoder(dec decoder, elemType *rtype, size uintptr, structName, fie
 		valueDecoder:            dec,
 		elemType:                elemType,
 		isElemPointerType:       elemType.Kind() == reflect.Ptr || elemType.Kind() == reflect.Map,
+		isElemUnmarshalJSONType: rtype_ptrTo(elemType).Implements(unmarshalJSONType),
 		size:                    size,
 		arrayPool: sync.Pool{
 			New: func() interface{} {
@@ -65,6 +67,9 @@ func copySlice(elemType *rtype, dst, src sliceHeader) int
 //go:linkname newArray reflect.unsafe_NewArray
 func newArray(*rtype, int) unsafe.Pointer
 
+//go:linkname typedmemmove reflect.typedmemmove
+func typedmemmove(t *rtype, dst, src unsafe.Pointer)
+
 func (d *sliceDecoder) errNumber(offset int64) *UnmarshalTypeError {
 	return &UnmarshalTypeError{
 		Value:  "number",
@@ -117,8 +122,11 @@ func (d *sliceDecoder) decodeStream(s *stream, depth int64, p unsafe.Pointer) er
 					copySlice(d.elemType, dst, src)
 				}
 				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
-				if d.isElemPointerType {
+				if d.isElemUnmarshalJSONType {
-					*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+					// assign new element to the slice
+					typedmemmove(d.elemType, ep, unsafe_New(d.elemType))
+				} else if d.isElemPointerType {
+					**(**unsafe.Pointer)(unsafe.Pointer(&ep)) = nil // initialize elem pointer
 				}
 				if err := d.valueDecoder.decodeStream(s, depth, ep); err != nil {
 					return err
@@ -231,8 +239,11 @@ func (d *sliceDecoder) decode(buf []byte, cursor, depth int64, p unsafe.Pointer)
 					copySlice(d.elemType, dst, src)
 				}
 				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
-				if d.isElemPointerType {
+				if d.isElemUnmarshalJSONType {
-					*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+					// assign new element to the slice
+					typedmemmove(d.elemType, ep, unsafe_New(d.elemType))
+				} else if d.isElemPointerType {
+					**(**unsafe.Pointer)(unsafe.Pointer(&ep)) = nil // initialize elem pointer
 				}
 				c, err := d.valueDecoder.decode(buf, cursor, depth, ep)
 				if err != nil {

decode_test.go

@@ -2931,6 +2931,268 @@ func TestDecodeSlice(t *testing.T) {
 	}
 }
 
+func TestDecodeMultipleUnmarshal(t *testing.T) {
+	data := []byte(`[{"AA":{"X":[{"a": "A"},{"b": "B"}],"Y":"y","Z":"z"},"BB":"bb"},{"AA":{"X":[],"Y":"y","Z":"z"},"BB":"bb"}]`)
+	var a []json.RawMessage
+	if err := json.Unmarshal(data, &a); err != nil {
+		t.Fatal(err)
+	}
+	if len(a) != 2 {
+		t.Fatalf("failed to decode: got %v", a)
+	}
+	t.Run("first", func(t *testing.T) {
+		data := a[0]
+		var v map[string]json.RawMessage
+		if err := json.Unmarshal(data, &v); err != nil {
+			t.Fatal(err)
+		}
+		if string(v["AA"]) != `{"X":[{"a": "A"},{"b": "B"}],"Y":"y","Z":"z"}` {
+			t.Fatalf("failed to decode. got %q", v["AA"])
+		}
+		var aa map[string]json.RawMessage
+		if err := json.Unmarshal(v["AA"], &aa); err != nil {
+			t.Fatal(err)
+		}
+		if string(aa["X"]) != `[{"a": "A"},{"b": "B"}]` {
+			t.Fatalf("failed to decode. got %q", v["X"])
+		}
+		var x []json.RawMessage
+		if err := json.Unmarshal(aa["X"], &x); err != nil {
+			t.Fatal(err)
+		}
+		if len(x) != 2 {
+			t.Fatalf("failed to decode: %v", x)
+		}
+		if string(x[0]) != `{"a": "A"}` {
+			t.Fatal("failed to decode")
+		}
+		if string(x[1]) != `{"b": "B"}` {
+			t.Fatal("failed to decode")
+		}
+	})
+	t.Run("second", func(t *testing.T) {
+		data := a[1]
+		var v map[string]json.RawMessage
+		if err := json.Unmarshal(data, &v); err != nil {
+			t.Fatal(err)
+		}
+		if string(v["AA"]) != `{"X":[],"Y":"y","Z":"z"}` {
+			t.Fatalf("failed to decode. got %q", v["AA"])
+		}
+		var aa map[string]json.RawMessage
+		if err := json.Unmarshal(v["AA"], &aa); err != nil {
+			t.Fatal(err)
+		}
+		if string(aa["X"]) != `[]` {
+			t.Fatalf("failed to decode. got %q", v["X"])
+		}
+		var x []json.RawMessage
+		if err := json.Unmarshal(aa["X"], &x); err != nil {
+			t.Fatal(err)
+		}
+		if len(x) != 0 {
+			t.Fatalf("failed to decode: %v", x)
+		}
+	})
+}
+
+func TestMultipleDecodeWithRawMessage(t *testing.T) {
+	original := []byte(`{
+		"Body": {
+			"List": [
+				{
+					"Returns": [
+						{
+							"Value": "10",
+							"nodeType": "Literal"
+						}
+					],
+					"nodeKind": "Return",
+					"nodeType": "Statement"
+				}
+			],
+			"nodeKind": "Block",
+			"nodeType": "Statement"
+		},
+		"nodeType": "Function"
+	}`)
+
+	var a map[string]json.RawMessage
+	if err := json.Unmarshal(original, &a); err != nil {
+		t.Fatal(err)
+	}
+	var b map[string]json.RawMessage
+	if err := json.Unmarshal(a["Body"], &b); err != nil {
+		t.Fatal(err)
+	}
+	var c []json.RawMessage
+	if err := json.Unmarshal(b["List"], &c); err != nil {
+		t.Fatal(err)
+	}
+	var d map[string]json.RawMessage
+	if err := json.Unmarshal(c[0], &d); err != nil {
+		t.Fatal(err)
+	}
+	var e []json.RawMessage
+	if err := json.Unmarshal(d["Returns"], &e); err != nil {
+		t.Fatal(err)
+	}
+	var f map[string]json.RawMessage
+	if err := json.Unmarshal(e[0], &f); err != nil {
+		t.Fatal(err)
+	}
+}
+
+type intUnmarshaler int
+
+func (u *intUnmarshaler) UnmarshalJSON(b []byte) error {
+	if *u != 0 {
+		return fmt.Errorf("failed to decode of slice with int unmarshaler")
+	}
+	*u = 10
+	return nil
+}
+
+type arrayUnmarshaler [5]int
+
+func (u *arrayUnmarshaler) UnmarshalJSON(b []byte) error {
+	if (*u)[0] != 0 {
+		return fmt.Errorf("failed to decode of slice with array unmarshaler")
+	}
+	(*u)[0] = 10
+	return nil
+}
+
+type mapUnmarshaler map[string]int
+
+func (u *mapUnmarshaler) UnmarshalJSON(b []byte) error {
+	if len(*u) != 0 {
+		return fmt.Errorf("failed to decode of slice with map unmarshaler")
+	}
+	*u = map[string]int{"a": 10}
+	return nil
+}
+
+type structUnmarshaler struct {
+	A int
+}
+
+func (u *structUnmarshaler) UnmarshalJSON(b []byte) error {
+	if u.A != 0 {
+		return fmt.Errorf("failed to decode of slice with struct unmarshaler")
+	}
+	u.A = 10
+	return nil
+}
+
+func TestSliceElemUnmarshaler(t *testing.T) {
+	t.Run("int", func(t *testing.T) {
+		var v []intUnmarshaler
+		if err := json.Unmarshal([]byte(`[1,2,3,4,5]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 5 {
+			t.Fatalf("failed to decode of slice with int unmarshaler: %v", v)
+		}
+		if v[0] != 10 {
+			t.Fatalf("failed to decode of slice with int unmarshaler: %v", v)
+		}
+		if err := json.Unmarshal([]byte(`[6]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 1 {
+			t.Fatalf("failed to decode of slice with int unmarshaler: %v", v)
+		}
+		if v[0] != 10 {
+			t.Fatalf("failed to decode of slice with int unmarshaler: %v", v)
+		}
+	})
+	t.Run("slice", func(t *testing.T) {
+		var v []json.RawMessage
+		if err := json.Unmarshal([]byte(`[1,2,3,4,5]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 5 {
+			t.Fatalf("failed to decode of slice with slice unmarshaler: %v", v)
+		}
+		if len(v[0]) != 1 {
+			t.Fatalf("failed to decode of slice with slice unmarshaler: %v", v)
+		}
+		if err := json.Unmarshal([]byte(`[6]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 1 {
+			t.Fatalf("failed to decode of slice with slice unmarshaler: %v", v)
+		}
+		if len(v[0]) != 1 {
+			t.Fatalf("failed to decode of slice with slice unmarshaler: %v", v)
+		}
+	})
+	t.Run("array", func(t *testing.T) {
+		var v []arrayUnmarshaler
+		if err := json.Unmarshal([]byte(`[1,2,3,4,5]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 5 {
+			t.Fatalf("failed to decode of slice with array unmarshaler: %v", v)
+		}
+		if v[0][0] != 10 {
+			t.Fatalf("failed to decode of slice with array unmarshaler: %v", v)
+		}
+		if err := json.Unmarshal([]byte(`[6]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 1 {
+			t.Fatalf("failed to decode of slice with array unmarshaler: %v", v)
+		}
+		if v[0][0] != 10 {
+			t.Fatalf("failed to decode of slice with array unmarshaler: %v", v)
+		}
+	})
+	t.Run("map", func(t *testing.T) {
+		var v []mapUnmarshaler
+		if err := json.Unmarshal([]byte(`[{"a":1},{"b":2},{"c":3},{"d":4},{"e":5}]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 5 {
+			t.Fatalf("failed to decode of slice with map unmarshaler: %v", v)
+		}
+		if v[0]["a"] != 10 {
+			t.Fatalf("failed to decode of slice with map unmarshaler: %v", v)
+		}
+		if err := json.Unmarshal([]byte(`[6]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 1 {
+			t.Fatalf("failed to decode of slice with map unmarshaler: %v", v)
+		}
+		if v[0]["a"] != 10 {
+			t.Fatalf("failed to decode of slice with map unmarshaler: %v", v)
+		}
+	})
+	t.Run("struct", func(t *testing.T) {
+		var v []structUnmarshaler
+		if err := json.Unmarshal([]byte(`[1,2,3,4,5]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 5 {
+			t.Fatalf("failed to decode of slice with struct unmarshaler: %v", v)
+		}
+		if v[0].A != 10 {
+			t.Fatalf("failed to decode of slice with struct unmarshaler: %v", v)
+		}
+		if err := json.Unmarshal([]byte(`[6]`), &v); err != nil {
+			t.Fatal(err)
+		}
+		if len(v) != 1 {
+			t.Fatalf("failed to decode of slice with struct unmarshaler: %v", v)
+		}
+		if v[0].A != 10 {
+			t.Fatalf("failed to decode of slice with struct unmarshaler: %v", v)
+		}
+	})
+}
+
 func TestInvalidTopLevelValue(t *testing.T) {
 	t.Run("invalid end of buffer", func(t *testing.T) {
 		var v struct{}