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Remove broken PySequence_Fast() function from the limited C API #55
Description
The limited C API has the function PySequence_Fast() which should be used with these macros:
PySequence_Fast_GET_SIZE()PySequence_Fast_GET_ITEM()PySequence_Fast_ITEMS()
Problem: none of these 3 macros work with the limited C API. The whole PySequence_Fast() API is broken in the limited C API.
Example:
#define PySequence_Fast_GET_ITEM(o, i)\
(PyList_Check(o) ? PyList_GET_ITEM((o), (i)) : PyTuple_GET_ITEM((o), (i)))PyList_GET_ITEM() and PyTuple_GET_ITEM() are not part of the limited C API, so PySequence_Fast_GET_ITEM() cannot be used in the limited C API.
I propose to remove PySequence_Fast() and these 3 macros from the limited C API, since they are incompatible and never worked with the limited C API.
Vote:
Activity
serhiy-storchaka commentedon Jan 29, 2025
I support this. It is clear to me that they were not excluded from the limited C API due to oversight.
PySequence_ITEMalso slipped in the limited C API. It was excluded in issue python/cpython#77919 (PR python/cpython#7477).encukou commentedon Jan 30, 2025
+1 for removing the macros; yes, they never worked in limited API (and since PEP 652 they were never “officially” part of limited API); moving them to
Include/cpythonis the right thing to do.The
PySequence_Fastfunction itself works. Third-party code can, theoretically, require a result ofPySequence_Fastas input.If y'all think it should go I won't block the removal, but I think it's unnecessary. As minor, benign mistake of the past, it doesn't need fixing.
vstinner commentedon Jan 30, 2025
Ping @erlend-aasland.
vstinner commentedon Feb 2, 2025
Thanks for voting. I close the issue.
@encukou:
At least, the function remains available in the stable ABI.