From 06dc5ac7489f23e33f88a2c6b46a6eacc25f890e Mon Sep 17 00:00:00 2001
From: Ahmed Semih Ozmekik <ahmed-semih@outlook.com>
Date: Thu, 12 Nov 2026 08:39:56 +0300
Subject: [PATCH] gh-158314: Fix test_parameters_deep_recursion on 32-bit ARM

_Py_make_parameters() uses only 48 bytes of C stack per level in a debug
build on 32-bit ARM, so 150_000 nested lists fit in the 8 MiB stack of
run_with_limited_c_stack() and no RecursionError is raised.  Nest
500_000 levels, as other tests with small C frames do.
---
 Lib/test/test_typing.py                                   | 8 +++++---
 .../Tests/2026-11-12-05-39-56.gh-issue-158314.SZiMPV.rst  | 3 +++
 2 files changed, 8 insertions(+), 3 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Tests/2026-11-12-05-39-56.gh-issue-158314.SZiMPV.rst

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 3879c49c714dd9..ab5b306ff6a7e4 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -53,7 +53,7 @@
 from test.support import (
     captured_stderr, cpython_only, requires_docstrings, import_helper, run_code,
     subTests, EqualToForwardRef,
-    exceeds_recursion_limit, run_with_limited_c_stack,
+    run_with_limited_c_stack,
     skip_wasi_stack_overflow, skip_emscripten_stack_overflow,
 )
 from test.typinganndata import (
@@ -5097,12 +5097,14 @@ class MM2(collections.abc.MutableMapping, MutableMapping[str, str]):
         self.assertEqual(MM2.__bases__, (collections.abc.MutableMapping, Generic))
 
     @cpython_only
-    @run_with_limited_c_stack()
+    @run_with_limited_c_stack(500_000)
     @skip_wasi_stack_overflow()
     @skip_emscripten_stack_overflow()
     def test_parameters_deep_recursion(self):
+        # _Py_make_parameters() has small C frames (48 bytes per level
+        # on 32-bit ARM), so 150_000 levels can fit in the limited C stack.
         x = [0]
-        for _ in range(exceeds_recursion_limit()):
+        for _ in range(500_000):
             x = [x]
         with self.assertRaisesRegex(RecursionError, "in __parameter__ calculation"):
             list[x].__parameters__
diff --git a/Misc/NEWS.d/next/Tests/2026-11-12-05-39-56.gh-issue-158314.SZiMPV.rst b/Misc/NEWS.d/next/Tests/2026-11-12-05-39-56.gh-issue-158314.SZiMPV.rst
new file mode 100644
index 00000000000000..cc547ae93d5773
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2026-11-12-05-39-56.gh-issue-158314.SZiMPV.rst
@@ -0,0 +1,3 @@
+Fix ``test_typing.GenericTests.test_parameters_deep_recursion`` on 32-bit
+ARM debug builds, where 150,000 nested lists did not exhaust the limited C
+stack.