Python 3.11.0

-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEz9yiRbEEPPKl+Xhl/+h0BBaL2EcFAmNWzOwACgkQ/+h0BBaL
 2EcepxAAmZLGMrL4D7Zxzo6N2ezkuiuoQH4JvxIUaB7cjU5h0GSUFlmcJQCHhCwk
 AvToQrmH/7uuuEZKST1fomtUE83wudfHhX2t+CMBdbLG1hIwhTfLNMTqFhONturF
 XlkVUcva1i9XrYZPLl1pIcBf1Sjm6pPW5QZ4BP1ZHJ5C2pHEzaBRFX/q0lU5aF9O
 z5nBBpnga2gShUTqM1VkXucU4lKXsi4blbn/Z8giganMXY1SXIsEOoCaDZYN1Hh/
 xQiOpSrjy/uSz4vGSNuPwp9J2lRlw8n4RBd/P7om01CrJMAKotH+62OqwhlQ8ydB
 ywp0kygtPtMdSK7F1WKMWkYX4CXfLpYwN0+x3Z3iYFBFiuzOFrUCQYgqqfEPNq+o
 bQxxnhAvYcOVINUub6oL23hgFZIoM6l54L66qujQVFM0usCY2f23Ikqd0Z7K8+6e
 uDRAvGiCHkbbfhdnfXzc/Wgj4zLaPnNs8S2s8ojK32NPV8gyWVBumcsRvlocfl6K
 hoA5wqeAXsOv+pFjkGtk90Yg+8R9n+n47//o6uYW/vvZtksm2wPm3hnuCA0WqPzN
 IM7SJE5VrtSRqQpXT9j4G3zyHDNT/Qhrh+cyBM5kgoPSdbU0ugZN8P7GWVtsFhmK
 rrHRns85gNZJ6qTN1pU22MybYCPIsg5Dt6+jZ8hJWIzOOy9apIk=
 =Ryd2
 -----END PGP SIGNATURE-----
gpgsig -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEz9yiRbEEPPKl+Xhl/+h0BBaL2EcFAmNW55YACgkQ/+h0BBaL
 2EfCLg//bMWtb/X3D+IM+9BIrpEscj/vw22zH9j8PIRd8iWfW80TNEIBh4uPEc0j
 SDTkA5bqN6CB7xqIxDlWQcJpGiImVZ2LzOw8HHye1QCfVZk741CF78UhEnb+hTbO
 gr7nIznytv+VdMSDRHTSgpnkRNQ9FjFEHLu7YQTMof5i/YmTxWZcsru6dTLlEutg
 F3+PfxbKwPgJkfare91X62XSQwyTL6k0mvl5+Sdq2WEQdgMqv4I8V9dHbnk9K3VI
 B+K2xsfIyWHrLDwQa3LBZj4YOKTwnwqlr1sEqO47NfasWaMYa1vBsktLVtPVQ3xS
 Hz0lLhJXJLzf5hmf2r4Tw1S5spn5ijsZ7CwK2Zl+1+dbJMpRoK4VeSSYy/OfEpwy
 8Hx1YitMyORF3HkGWa+pPYPNaIOw4S/EQQPYd5osg3NnknYjkkKZZaliq7EZra7c
 GANPJamXhHREQyhux9KeiYZer3SU3CSXopyxm8ClcBZJAiAOjhAdeOk+Q4Ta9T6+
 gRWBOrelroyFTWHsOd8V7gSz3XJNuAzlNZ/+1Oj/7Em+5DGLFcxJrZGLxn+hruZ5
 GPK9IQXbURAuxqVrqCzw2tzf/NzJr0fs4QDYEVI95pfLjzk1tuJ5WR6zFNC0COK2
 qw8TTvXglsvHqVMnK8u73GVSTv1UGYqbQH9uAeEikAQYr3TTdZo=
 =dsZm
 -----END PGP SIGNATURE-----

Merge tag 'v3.11.0' into 3.11

Python 3.11.0

Lib/test/test_frame.py

@@ -326,5 +326,69 @@ def f():
                 gc.enable()
 
 
+    @support.cpython_only
+    def test_sneaky_frame_object(self):
+
+        def trace(frame, event, arg):
+            """
+            Don't actually do anything, just force a frame object to be created.
+            """
+
+        def callback(phase, info):
+            """
+            Yo dawg, I heard you like frames, so I'm allocating a frame while
+            you're allocating a frame, so you can have a frame while you have a
+            frame!
+            """
+            nonlocal sneaky_frame_object
+            sneaky_frame_object = sys._getframe().f_back
+            # We're done here:
+            gc.callbacks.remove(callback)
+
+        def f():
+            while True:
+                yield
+
+        old_threshold = gc.get_threshold()
+        old_callbacks = gc.callbacks[:]
+        old_enabled = gc.isenabled()
+        old_trace = sys.gettrace()
+        try:
+            # Stop the GC for a second while we set things up:
+            gc.disable()
+            # Create a paused generator:
+            g = f()
+            next(g)
+            # Move all objects to the oldest generation, and tell the GC to run
+            # on the *very next* allocation:
+            gc.collect()
+            gc.set_threshold(1, 0, 0)
+            # Okay, so here's the nightmare scenario:
+            # - We're tracing the resumption of a generator, which creates a new
+            #   frame object.
+            # - The allocation of this frame object triggers a collection
+            #   *before* the frame object is actually created.
+            # - During the collection, we request the exact same frame object.
+            #   This test does it with a GC callback, but in real code it would
+            #   likely be a trace function, weakref callback, or finalizer.
+            # - The collection finishes, and the original frame object is
+            #   created. We now have two frame objects fighting over ownership
+            #   of the same interpreter frame!
+            sys.settrace(trace)
+            gc.callbacks.append(callback)
+            sneaky_frame_object = None
+            gc.enable()
+            next(g)
+            # g.gi_frame should be the the frame object from the callback (the
+            # one that was *requested* second, but *created* first):
+            self.assertIs(g.gi_frame, sneaky_frame_object)
+        finally:
+            gc.set_threshold(*old_threshold)
+            gc.callbacks[:] = old_callbacks
+            sys.settrace(old_trace)
+            if old_enabled:
+                gc.enable()
+
+
 if __name__ == "__main__":
     unittest.main()