Fix false-positive trigger syntax error (#2360)

sqlparser/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.29.0-dev
+
+- Fix false-positive warnings about `AS` aliases in subqueries used in triggers.
+
 ## 0.28.0
 
 - Support the `unhex` function added in sqlite 3.41.0

sqlparser/lib/src/analysis/steps/linting_visitor.dart

@@ -6,10 +6,24 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
   final EngineOptions options;
   final AnalysisContext context;
 
-  bool _isTopLevelStatement = true;
+  bool _isInTopLevelTriggerStatement = false;
 
   LintingVisitor(this.options, this.context);
 
+  @override
+  void visitBaseSelectStatement(BaseSelectStatement stmt, void arg) {
+    if (_isInTopLevelTriggerStatement) {
+      // If this select statement is used as a subqery, we're no longer in a
+      // top-level trigger statements.
+      final saved = _isInTopLevelTriggerStatement;
+      _isInTopLevelTriggerStatement = stmt.parent is Block;
+      super.visitBaseSelectStatement(stmt, arg);
+      _isInTopLevelTriggerStatement = saved;
+    } else {
+      super.visitBaseSelectStatement(stmt, arg);
+    }
+  }
+
   @override
   void visitBinaryExpression(BinaryExpression e, void arg) {
     final operator = e.operator.type;
@@ -141,10 +155,10 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
 
   @override
   void visitCreateTriggerStatement(CreateTriggerStatement e, void arg) {
-    final topLevelBefore = _isTopLevelStatement;
-    _isTopLevelStatement = false;
+    final topLevelBefore = _isInTopLevelTriggerStatement;
+    _isInTopLevelTriggerStatement = true;
     visitChildren(e, arg);
-    _isTopLevelStatement = topLevelBefore;
+    _isInTopLevelTriggerStatement = topLevelBefore;
   }
 
   @override
@@ -172,7 +186,7 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
   @override
   void visitDefaultValues(DefaultValues e, void arg) {
     // `DEFAULT VALUES` is not supported in a trigger, see https://www.sqlite.org/lang_insert.html
-    if (!_isTopLevelStatement) {
+    if (_isInTopLevelTriggerStatement) {
       context.reportError(
         AnalysisError(
           type: AnalysisErrorType.synctactic,
@@ -304,7 +318,7 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
 
   @override
   void visitRaiseExpression(RaiseExpression e, void arg) {
-    if (_isTopLevelStatement) {
+    if (!_isInTopLevelTriggerStatement) {
       context.reportError(AnalysisError(
         type: AnalysisErrorType.raiseMisuse,
         relevantNode: e,
@@ -328,7 +342,7 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
 
     // https://www.sqlite.org/lang_returning.html#limitations_and_caveats
     // Returning is not allowed in triggers
-    if (!_isTopLevelStatement) {
+    if (_isInTopLevelTriggerStatement) {
       context.reportError(AnalysisError(
         type: AnalysisErrorType.illegalUseOfReturning,
         message: 'RETURNING is not allowed in triggers',
@@ -421,7 +435,7 @@ class LintingVisitor extends RecursiveVisitor<void, void> {
     if (parent is HasPrimarySource && parent.table == e) {
       // The source of a `INSERT`, `UPDATE` or `DELETE` statement must not have
       // an alias in `CREATE TRIGGER` statements.
-      if (!_isTopLevelStatement && e.as != null) {
+      if (_isInTopLevelTriggerStatement && e.as != null) {
         context.reportError(AnalysisError(
           type: AnalysisErrorType.synctactic,
           message:

sqlparser/test/analysis/errors/syntax_error_test.dart

@@ -107,6 +107,14 @@ void main() {
                 'END;')
             .expectError('demo d', type: AnalysisErrorType.synctactic);
       });
+
+      test('allowed in subquery', () {
+        engine.analyze('''
+          CREATE TRIGGER tgr AFTER DELETE ON demo BEGIN
+            INSERT INTO demo (content) SELECT content FROM demo AS ok;
+          END;
+        ''').expectNoError();
+      });
     });
   });
 }