fix: remove incorrect Py_DECREF after PyList_SetItem#108
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Vitalymt wants to merge 1 commit intoyandex:mainfrom
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fix: remove incorrect Py_DECREF after PyList_SetItem#108Vitalymt wants to merge 1 commit intoyandex:mainfrom
Vitalymt wants to merge 1 commit intoyandex:mainfrom
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PyList_SetItem() steals a reference to its third argument regardless of whether the call succeeds or fails. Calling Py_DECREF(marker) in the error path causes a double-release since the reference was already consumed by PyList_SetItem. Removed the redundant Py_DECREF and added a comment explaining the reference semantics for both the cython and cython_py2 copies. Fixes yandex#106
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Problem
PyList_SetItem()steals a reference to its third argument — even when the call fails. The current error path callsPy_DECREF(marker)after a failedPyList_SetItem(), which double-releases the reference since ownership was already transferred.This is a use-after-free that can cause undefined behavior (crash, memory corruption) depending on allocator state and GC timing.
Fix
Removed the incorrect
Py_DECREF(marker)in both thecythonandcython_py2copies ofCythonFunction.c, and added a comment explaining the reference-stealing semantics for future maintainers.The
Py_DECREF(fromlist)is retained sincefromliststill needs to be cleaned up.Fixes #106