fix invalid escape character

decode_test.go

@@ -810,7 +810,7 @@ func TestDecoder(t *testing.T) {
 		},
 		{
 			"a: \"\\0\"\n",
-			map[string]string{"a": "\\0"},
+			map[string]string{"a": "\x00"},
 		},
 		{
 			"b: 2\na: 1\nd: 4\nc: 3\nsub:\n  e: 5\n",

lexer/lexer_test.go

@@ -1347,7 +1347,7 @@ t4: 2098-01-09T10:40:47Z
 					Type:          token.DoubleQuoteType,
 					CharacterType: token.CharacterTypeIndicator,
 					Indicator:     token.QuotedScalarIndicator,
-					Value:         "\\0",
+					Value:         "\x00",
 					Origin:        " \"\\0\"",
 				},
 			},

scanner/scanner.go

@@ -454,10 +454,20 @@ func (s *Scanner) scanDoubleQuote(ctx *Context) (*token.Token, error) {
 				progress = 1
 				ctx.addOriginBuf(nextChar)
 				value = append(value, nextChar)
+			case '0':
+				progress = 1
+				ctx.addOriginBuf(nextChar)
+				value = append(value, '\x00')
 			case ' ':
 				// skip escape character.
 			default:
-				value = append(value, c)
+				s.progressColumn(ctx, 1)
+				return nil, ErrInvalidToken(
+					token.Invalid(
+						fmt.Sprintf("found unknown escape character %q", nextChar),
+						string(ctx.obuf), s.pos(),
+					),
+				)
 			}
 			idx += progress
 			s.progressColumn(ctx, progress)

yaml_test_suite_test.go

@@ -50,7 +50,6 @@ var failureTestNames = []string{
 	"implicit-flow-mapping-key-on-one-line", // no json.
 	"invalid-comment-after-comma",
 	"invalid-comment-after-end-of-flow-sequence",
-	"invalid-escape-in-double-quoted-string",
 	"invalid-tag",
 	"key-with-anchor-after-missing-explicit-mapping-value",
 	"leading-tabs-in-double-quoted/02",