Fix crash at trailing comma in FROM clause

sqlparser/lib/src/reader/parser.dart

@@ -62,7 +62,12 @@ class Parser {
 
   bool get _isAtEnd => _peek.type == TokenType.eof;
   Token get _peek => tokens[_current];
-  Token get _peekNext => tokens[_current + 1];
+  Token? get _peekNext {
+    if (_isAtEnd) return null;
+
+    return tokens[_current + 1];
+  }
+
   Token get _previous => tokens[_current - 1];
 
   bool _match(Iterable<TokenType> types) {
@@ -96,14 +101,14 @@ class Parser {
   /// "NOT" followed by [type]. Does not consume any tokens.
   bool _checkWithNot(TokenType type) {
     if (_check(type)) return true;
-    if (_check(TokenType.not) && _peekNext.type == type) return true;
+    if (_check(TokenType.not) && _peekNext?.type == type) return true;
     return false;
   }
 
   /// Like [_checkWithNot], but with more than one token type.
   bool _checkAnyWithNot(List<TokenType> types) {
     if (types.any(_check)) return true;
-    if (_check(TokenType.not) && types.contains(_peekNext.type)) return true;
+    if (_check(TokenType.not) && types.contains(_peekNext?.type)) return true;
     return false;
   }
 
@@ -866,7 +871,7 @@ class Parser {
     if (_peek is KeywordToken) {
       // Improve error messages for possible function calls, https://github.com/simolus3/drift/discussions/2277
       if (tokens.length > _current + 1 &&
-          _peekNext.type == TokenType.leftParen) {
+          _peekNext?.type == TokenType.leftParen) {
         _error(
           'Expected an expression here, but got a reserved keyword. Did you '
           'mean to call a function? Try wrapping the keyword in double quotes.',
@@ -1346,6 +1351,7 @@ class Parser {
     // Can either be a list of <TableOrSubquery> or a join. Joins also start
     // with a TableOrSubquery, so let's first parse that.
     final start = _tableOrSubquery();
+
     // parse join, if there is one
     return _joinClause(start) ?? start;
   }
@@ -1399,7 +1405,7 @@ class Parser {
     final joins = <Join>[];
 
     while (operator != null) {
-      final first = _peekNext;
+      final first = _peek;
 
       final subquery = _tableOrSubquery();
       final constraint = _joinConstraint();
@@ -2786,10 +2792,8 @@ class Parser {
 
     DeferrableClause? deferrable;
     if (_checkWithNot(TokenType.deferrable)) {
-      final first = _peekNext;
-
-      final not = _matchOne(TokenType.not);
-      _consume(TokenType.deferrable);
+      final not = _matchOneAndGet(TokenType.not);
+      final deferrableToken = _consume(TokenType.deferrable);
 
       InitialDeferrableMode? mode;
       if (_matchOne(TokenType.initially)) {
@@ -2802,7 +2806,8 @@ class Parser {
         }
       }
 
-      deferrable = DeferrableClause(not, mode)..setSpan(first, _previous);
+      deferrable = DeferrableClause(not != null, mode)
+        ..setSpan(not ?? deferrableToken, _previous);
     }
 
     return ForeignKeyClause(

sqlparser/test/parser/errors_test.dart

@@ -1,6 +1,8 @@
 import 'package:sqlparser/sqlparser.dart';
 import 'package:test/test.dart';
 
+import 'utils.dart';
+
 void main() {
   test('WITH without following statement', () {
     expectError('WITH foo AS (SELECT * FROM bar)',
@@ -12,7 +14,7 @@ void main() {
       expectError('SELECT replace(a, b, c);', [
         isParsingError(
           message: contains('Did you mean to call a function?'),
-          lexeme: 'replace',
+          span: 'replace',
         ),
       ]);
     });
@@ -21,14 +23,22 @@ void main() {
       expectError('SELECT group FROM foo;', [
         isParsingError(
           message: contains('Did you mean to use it as a column?'),
-          lexeme: 'group',
+          span: 'group',
         ),
       ]);
 
       expectError('CREATE TABLE x (table TEXT NOT NULL, foo INTEGER);', [
         isParsingError(
           message: 'Expected a column name (got keyword TABLE)',
-          lexeme: 'table',
+          span: 'table',
+        ),
+      ]);
+    });
+
+    test('recovers from invalid comma after table reference', () {
+      expectError('SELECT * FROM table_name,', [
+        isParsingError(
+          message: 'Expected a table name or a nested select statement',
         ),
       ]);
     });
@@ -40,17 +50,3 @@ void expectError(String sql, errorsMatcher) {
 
   expect(parsed.errors, errorsMatcher);
 }
-
-TypeMatcher<ParsingError> isParsingError({message, lexeme}) {
-  var matcher = isA<ParsingError>();
-
-  if (lexeme != null) {
-    matcher = matcher.having((e) => e.token.lexeme, 'token.lexeme', lexeme);
-  }
-
-  if (message != null) {
-    matcher = matcher.having((e) => e.message, 'message', message);
-  }
-
-  return matcher;
-}

sqlparser/test/parser/utils.dart

@@ -54,11 +54,16 @@ void expectParseError(
 }) {
   final result = SqlEngine().parse(sql);
 
-  expect(result.errors, [
-    isA<ParsingError>()
-        .having((e) => e.message, 'message', wrapMatcher(message))
-        .having((e) => e.token.span.text, 'span', wrapMatcher(span))
-  ]);
+  expect(result.errors, [isParsingError(message: message, span: span)]);
+}
+
+TypeMatcher<ParsingError> isParsingError({
+  dynamic message = anything,
+  dynamic span = anything,
+}) {
+  return isA<ParsingError>()
+      .having((e) => e.message, 'message', wrapMatcher(message))
+      .having((e) => e.token.span.text, 'span', wrapMatcher(span));
 }
 
 FileSpan fakeSpan(String content) {