gh-95185: Check recursion depth in the AST constructor (#95186)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 480089a..9734218 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -793,6 +793,27 @@ class AST_Tests(unittest.TestCase):
                     return self
         enum._test_simple_enum(_Precedence, ast._Precedence)
 
+    @support.cpython_only
+    def test_ast_recursion_limit(self):
+        fail_depth = sys.getrecursionlimit() * 3
+        crash_depth = sys.getrecursionlimit() * 300
+        success_depth = int(fail_depth * 0.75)
+
+        def check_limit(prefix, repeated):
+            expect_ok = prefix + repeated * success_depth
+            ast.parse(expect_ok)
+            for depth in (fail_depth, crash_depth):
+                broken = prefix + repeated * depth
+                details = "Compiling ({!r} + {!r} * {})".format(
+                            prefix, repeated, depth)
+                with self.assertRaises(RecursionError, msg=details):
+                    ast.parse(broken)
+
+        check_limit("a", "()")
+        check_limit("a", ".b")
+        check_limit("a", "[0]")
+        check_limit("a", "*a")
+
 
 class ASTHelpers_Test(unittest.TestCase):
     maxDiff = None