[3.10] bpo-46707: Avoid potential exponential backtracking in some syntax errors (GH-31241). (GH-31242)
(cherry picked from commit b71dc71905ab674ccaa4a56230d17a28f61c325c)
Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index ac5a41c..09c0d56 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -1617,6 +1617,14 @@ def test_error_on_parser_stack_overflow(self):
with self.assertRaises(MemoryError):
compile(source, "<string>", mode)
+ @support.cpython_only
+ def test_deep_invalid_rule(self):
+ # Check that a very deep invalid rule in the PEG
+ # parser doesn't have exponential backtracking.
+ source = "d{{{{{{{{{{{{{{{{{{{{{{{{{```{{{{{{{ef f():y"
+ with self.assertRaises(SyntaxError):
+ compile(source, "<string>", "exec")
+
def test_main():
support.run_unittest(SyntaxTestCase)