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GH-100964: Fix reference cycle in exhausted generator frames #141112

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GH-100964: Fix reference cycle in exhausted generator frames #141112

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bf5a967
Move frame->previous=NULL
savannahostrowski Nov 6, 2025
d4abe9b
Cleanup
savannahostrowski Nov 6, 2025
bd6111e
📜🤖 Added by blurb_it.
blurb-it[bot] Nov 6, 2025
3878626
Merge branch 'reference-cycle' of https://github.com/savannahostrowsk…
savannahostrowski Nov 6, 2025
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12 changes: 12 additions & 0 deletions Lib/test/test_generators.py
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Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,18 @@ def gen():
self.assertEqual(len(resurrected), 1)
self.assertIsInstance(resurrected[0].gi_code, types.CodeType)

def test_exhausted_generator_frame_cycle(self):
def g():
yield

generator = g()
frame = generator.gi_frame
self.assertIsNone(frame.f_back)
next(generator)
self.assertIsNone(frame.f_back)
next(generator, None)
self.assertIsNone(frame.f_back)


class GeneratorTest(unittest.TestCase):

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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2025-11-06-05-21-25.gh-issue-100964.TxPf1b.rst
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@@ -0,0 +1 @@
Fix reference cycle in exhausted generator frames
2 changes: 1 addition & 1 deletion Python/ceval.c
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Expand Up @@ -1842,9 +1842,9 @@ clear_gen_frame(PyThreadState *tstate, _PyInterpreterFrame * frame)
tstate->exc_info = gen->gi_exc_state.previous_item;
gen->gi_exc_state.previous_item = NULL;
assert(frame->frame_obj == NULL || frame->frame_obj->f_frame == frame);
frame->previous = NULL;
_PyFrame_ClearExceptCode(frame);
_PyErr_ClearExcState(&gen->gi_exc_state);
frame->previous = NULL;
}

void
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