fix: infinite recursion with SQL params (#555)

Fixes #554 and maybe #516

Author: juleswritescode

crates/pgt_treesitter/src/context/mod.rs

@@ -470,7 +470,9 @@ impl<'a> TreesitterContext<'a> {
  }
 
  // We have arrived at the leaf node
- if current_node.child_count() == 0 {
+ if current_node.child_count() == 0
+ || current_node.first_child_for_byte(self.position).is_none()
+ {
  self.node_under_cursor = Some(NodeUnderCursor::from(current_node));
  return;
  }
@@ -1214,4 +1216,43 @@ mod tests {
  _ => unreachable!(),
  }
  }
+
+ #[test]
+ fn does_not_overflow_callstack_on_smaller_treesitter_child() {
+ let query = format!(
+ r#"select * from persons where id = @i{}d;"#,
+ QueryWithCursorPosition::cursor_marker()
+ );
+
+ /*
+ The query (currently) yields the following treesitter tree for the WHERE clause:
+
+ where [29..43] 'where id = @id'
+ keyword_where [29..34] 'where'
+ binary_expression [35..43] 'id = @id'
+ field [35..37] 'id'
+ identifier [35..37] 'id'
+ = [38..39] '='
+ field [40..43] '@id'
+ identifier [40..43] '@id'
+ @ [40..41] '@'
+
+ You can see that the '@' is a child of the "identifier" but has a range smaller than its parent's.
+ This would crash our context parsing because, at position 42, we weren't at the leaf node but also couldn't
+ go to a child on that position.
+ */
+
+ let (position, text) = QueryWithCursorPosition::from(query).get_text_and_position();
+
+ let tree = get_tree(text.as_str());
+
+ let params = TreeSitterContextParams {
+ position: (position as u32).into(),
+ text: &text,
+ tree: &tree,
+ };
+
+ // should simply not panic
+ let _ = TreesitterContext::new(params);
+ }
 }