jsonparse: Fix a bug allowing a trailing comma in objects

1 files changed, 22 insertions, 11 deletions

diff --git a/internal/jsonparse/parse.go b/internal/jsonparse/parse.go
index 5547df4..ce71a65 100644
--- a/internal/jsonparse/parse.go
+++ b/internal/jsonparse/parse.go
@@ -279,7 +279,8 @@ type Parser struct {
 	// rule; they need some special assignments:
 	//
 	//   {   object: waiting for key to start or '}'
-	//   »   object: reading key / waiting for colon
+	//   }   object: waiting for key to start
+	//   :   object: reading key / waiting for colon
 	//   o   object: reading value / waiting for ',' or '}'
 	//
 	//   [   array: waiting for item to start or ']'
@@ -298,17 +299,17 @@ type Parser struct {
 	//   stack   processed
 	//   ?
 	//   {       {
-	//   »"      {"
-	//   »"      {"x
-	//   »       {"x"
+	//   :"      {"
+	//   :"      {"x
+	//   :       {"x"
 	//   o?      {"x":
 	//   o"      {"x":"
 	//   o"      {"x":"y
 	//   o       {"x":"y"
-	//   {       {"x":"y",
-	//   »"      {"x":"y","
-	//   »"      {"x":"y","a
-	//   »       {"x":"y","a"
+	//   }       {"x":"y",
+	//   :"      {"x":"y","
+	//   :"      {"x":"y","a
+	//   :       {"x":"y","a"
 	//   o?      {"x":"y","a":
 	//   o"      {"x":"y","a":"
 	//   o"      {"x":"y","a":"b
@@ -627,7 +628,7 @@ func (par *Parser) HandleRune(c rune, isRune bool) (RuneType, error) {
 		case 0x0020, 0x000A, 0x000D, 0x0009:
 			return RuneTypeSpace, nil
 		case '"':
-			par.replaceState(RuneTypeStringEnd)
+			par.replaceState(RuneTypeObjectColon)
 			return par.pushState(RuneTypeStringBeg), nil
 		case '}':
 			par.popState()
@@ -635,7 +636,17 @@ func (par *Parser) HandleRune(c rune, isRune bool) (RuneType, error) {
 		default:
 			return RuneTypeError, &InvalidCharacterError{c, isRune, "looking for beginning of object key string"}
 		}
-	case RuneTypeStringEnd: // waiting for ':'
+	case RuneTypeObjectEnd: // waiting for key to start
+		switch c {
+		case 0x0020, 0x000A, 0x000D, 0x0009:
+			return RuneTypeSpace, nil
+		case '"':
+			par.replaceState(RuneTypeObjectColon)
+			return par.pushState(RuneTypeStringBeg), nil
+		default:
+			return RuneTypeError, &InvalidCharacterError{c, isRune, "looking for beginning of object key string"}
+		}
+	case RuneTypeObjectColon: // waiting for ':'
 		switch c {
 		case 0x0020, 0x000A, 0x000D, 0x0009:
 			return RuneTypeSpace, nil
@@ -651,7 +662,7 @@ func (par *Parser) HandleRune(c rune, isRune bool) (RuneType, error) {
 		case 0x0020, 0x000A, 0x000D, 0x0009:
 			return RuneTypeSpace, nil
 		case ',':
-			par.replaceState(RuneTypeObjectBeg)
+			par.replaceState(RuneTypeObjectEnd)
 			return RuneTypeObjectComma, nil
 		case '}':
 			par.popState()