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bpo-44553: Correct failure in tp_new for the union object #27008

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Jul 3, 2021
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bpo-44553: Correct failure in tp_new for the union object #27008

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4 changes: 2 additions & 2 deletions Objects/unionobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -490,10 +490,10 @@ _Py_Union(PyObject *args)
}

result->args = dedup_and_flatten_args(args);
_PyObject_GC_TRACK(result);
if (result->args == NULL) {
PyObject_GC_Del(result);
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@Fidget-Spinner For next occasions, the problem with this is that PyObject_GC_Del cannot be called like that because it overrides a bunch of cleanups like the call to _Py_ForgetReference and other possible handling.

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Sorry bout that. I'll keep that in mind in the future.

BTW, does this mean this should be changed as well? https://github.com/python/cpython/blob/main/Objects/genericaliasobject.c#L654
I'm confused as to why it doesn't break the buildbots, or maybe because none of our tests make the object setup fail so PyObject_GC_Del is never called?

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Yes, that has exactly the same problem. I assume is not being reaches by the tests and that's why we are not seeing corruption.

Py_DECREF(result);
return NULL;
}
_PyObject_GC_TRACK(result);
return (PyObject*)result;
}