Merge pull request #682 from benluddy/textunmarshaler-bytestringtostring

Use TextUnmarshaler on byte strings with ByteStringToStringAllowed.

Author: fxamacker

decode.go

@@ -1570,7 +1570,7 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 			return err
 		}
 		copied = copied || converted
-		return fillByteString(t, b, !copied, v, d.dm.byteStringToString, d.dm.binaryUnmarshaler)
+		return fillByteString(t, b, !copied, v, d.dm.byteStringToString, d.dm.binaryUnmarshaler, d.dm.textUnmarshaler)
 
 	case cborTypeTextString:
 		b, err := d.parseTextString()
@@ -1629,7 +1629,7 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 				return nil
 			}
 			if tInfo.nonPtrKind == reflect.Slice || tInfo.nonPtrKind == reflect.Array {
-				return fillByteString(t, b, !copied, v, ByteStringToStringForbidden, d.dm.binaryUnmarshaler)
+				return fillByteString(t, b, !copied, v, ByteStringToStringForbidden, d.dm.binaryUnmarshaler, d.dm.textUnmarshaler)
 			}
 			if bi.IsUint64() {
 				return fillPositiveInt(t, bi.Uint64(), v)
@@ -1652,7 +1652,7 @@ func (d *decoder) parseToValue(v reflect.Value, tInfo *typeInfo) error { //nolin
 				return nil
 			}
 			if tInfo.nonPtrKind == reflect.Slice || tInfo.nonPtrKind == reflect.Array {
-				return fillByteString(t, b, !copied, v, ByteStringToStringForbidden, d.dm.binaryUnmarshaler)
+				return fillByteString(t, b, !copied, v, ByteStringToStringForbidden, d.dm.binaryUnmarshaler, d.dm.textUnmarshaler)
 			}
 			if bi.IsInt64() {
 				return fillNegativeInt(t, bi.Int64(), v)
@@ -3180,7 +3180,7 @@ func fillFloat(t cborType, val float64, v reflect.Value) error {
 	return &UnmarshalTypeError{CBORType: t.String(), GoType: v.Type().String()}
 }
 
-func fillByteString(t cborType, val []byte, shared bool, v reflect.Value, bsts ByteStringToStringMode, bum BinaryUnmarshalerMode) error {
+func fillByteString(t cborType, val []byte, shared bool, v reflect.Value, bsts ByteStringToStringMode, bum BinaryUnmarshalerMode, tum TextUnmarshalerMode) error {
 	if bum == BinaryUnmarshalerByteString && reflect.PointerTo(v.Type()).Implements(typeBinaryUnmarshaler) {
 		if v.CanAddr() {
 			v = v.Addr()
@@ -3193,9 +3193,26 @@ func fillByteString(t cborType, val []byte, shared bool, v reflect.Value, bsts B
 		}
 		return errors.New("cbor: cannot set new value for " + v.Type().String())
 	}
-	if bsts != ByteStringToStringForbidden && v.Kind() == reflect.String {
-		v.SetString(string(val))
-		return nil
+	if bsts != ByteStringToStringForbidden {
+		if tum == TextUnmarshalerTextString && reflect.PointerTo(v.Type()).Implements(typeTextUnmarshaler) {
+			if v.CanAddr() {
+				v = v.Addr()
+				if u, ok := v.Interface().(encoding.TextUnmarshaler); ok {
+					// The contract of TextUnmarshaler forbids retaining the input
+					// bytes, so no copying is required even if val is shared.
+					if err := u.UnmarshalText(val); err != nil {
+						return fmt.Errorf("cbor: cannot unmarshal text for %s: %w", v.Type(), err)
+					}
+					return nil
+				}
+			}
+			return errors.New("cbor: cannot set new value for " + v.Type().String())
+		}
+
+		if v.Kind() == reflect.String {
+			v.SetString(string(val))
+			return nil
+		}
 	}
 	if v.Kind() == reflect.Slice && v.Type().Elem().Kind() == reflect.Uint8 {
 		src := val

decode_test.go

@@ -10779,6 +10779,15 @@ func TestTextUnmarshalerMode(t *testing.T) {
 			in:   []byte("\x65hello"), // "hello"
 			want: testTextUnmarshaler("hello"),
 		},
+		{
+			name: "UnmarshalText is called for byte string with TextUnmarshalerTextString and ByteStringToStringAllowed",
+			opts: DecOptions{
+				TextUnmarshaler:    TextUnmarshalerTextString,
+				ByteStringToString: ByteStringToStringAllowed,
+			},
+			in:   []byte("\x45hello"), // 'hello'
+			want: testTextUnmarshaler("UnmarshalText"),
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			dm, err := tc.opts.DecMode()