Import upstream CPython branch '3.14'

Summary:
Python `3.14.0rc1+` (`3.14`) was **published** on 2025-08-04 13:01:39+00:00.

# Commit Info

Base: (`3.14.0rc1+`) - `134ca903b30d891c9b9bc8fe565139251d30fcbd` (commit date: 2025-08-04 10:34:16+00:00)

Imported: (`3.14.0rc1+`) - `3.14` (commit date: 2025-08-04 13:01:39+00:00)

# Files added

```javascript
Misc/NEWS.d/next/Library/2025-07-25-09-21-56.gh-issue-130522.Crwq68.rst
```

Reviewed By: zsol, itamaro

Differential Revision: D79638133

fbshipit-source-id: 8f72a0e8e0ce40a123794d92367d9316487f2586

Author: generatedunixname1734921407115435

Lib/test/test_threading.py

@@ -1993,6 +1993,23 @@ def modify_file():
             t.start()
             t.join()
 
+    def test_dummy_thread_on_interpreter_shutdown(self):
+        # GH-130522: When `threading` held a reference to itself and then a
+        # _DummyThread() object was created, destruction of the dummy thread
+        # would emit an unraisable exception at shutdown, due to a lock being
+        # destroyed.
+        code = """if True:
+        import sys
+        import threading
+
+        threading.x = sys.modules[__name__]
+        x = threading._DummyThread()
+        """
+        rc, out, err = assert_python_ok("-c", code)
+        self.assertEqual(rc, 0)
+        self.assertEqual(out, b"")
+        self.assertEqual(err, b"")
+
 
 class ThreadRunFail(threading.Thread):
     def run(self):

Lib/threading.py

@@ -1421,7 +1421,7 @@ def __init__(self, dummy_thread):
         # the related _DummyThread will be kept forever!
         _thread_local_info._track_dummy_thread_ref = self
 
-    def __del__(self):
+    def __del__(self, _active_limbo_lock=_active_limbo_lock, _active=_active):
         with _active_limbo_lock:
             if _active.get(self._tident) is self._dummy_thread:
                 _active.pop(self._tident, None)

Misc/NEWS.d/next/Library/2025-07-25-09-21-56.gh-issue-130522.Crwq68.rst

@@ -0,0 +1,2 @@
+Fix unraisable :exc:`TypeError` raised during :term:`interpreter shutdown`
+in the :mod:`threading` module.