gh-113297: Fix segfault in compiler for with statement with 19 context managers (#113327)

Lib/test/test_syntax.py

@@ -2017,6 +2017,7 @@ Invalid expressions in type scopes:
 
 import re
 import doctest
+import textwrap
 import unittest
 
 from test import support
@@ -2279,6 +2280,31 @@ if x:
         code += f"{' '*4*12}pass"
         self._check_error(code, "too many statically nested blocks")
 
+    @support.cpython_only
+    def test_with_statement_many_context_managers(self):
+        # See gh-113297
+
+        def get_code(n):
+            code = textwrap.dedent("""
+                def bug():
+                    with (
+                    a
+                """)
+            for i in range(n):
+                code += f"    as a{i}, a\n"
+            code += "): yield a"
+            return code
+
+        CO_MAXBLOCKS = 20  # static nesting limit of the compiler
+
+        for n in range(CO_MAXBLOCKS):
+            with self.subTest(f"within range: {n=}"):
+                compile(get_code(n), "<string>", "exec")
+
+        for n in range(CO_MAXBLOCKS, CO_MAXBLOCKS + 5):
+            with self.subTest(f"out of range: {n=}"):
+                self._check_error(get_code(n), "too many statically nested blocks")
+
     def test_barry_as_flufl_with_syntax_errors(self):
         # The "barry_as_flufl" rule can produce some "bugs-at-a-distance" if
         # is reading the wrong token in the presence of syntax errors later