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C API: Remove deprecated PySlice_GetIndicesEx(), or remove the deprecation #158077
Description
@serhiy-storchaka deprecated the PySlice_GetIndicesEx() function in Python 3.6.1.
We are now at Python 3.16, 10 releases later. So should we remove PySlice_GetIndicesEx() functon? Or should we keep it just remove the deprecation and keep it forever?
In PyPI top 15,000 projects (at 2026-09-17), I found 79 projects by searching for PySlice_GetIndicesEx:
- PyICU-binary (2.7.4)
- PyQt5 (5.15.11)
- Theano (1.0.5)
- Theano-PyMC (1.1.2)
- arize_phoenix_sqlean (0.1.2)
- biopython (1.88)
- bitarray-hardbyte (2.3.8)
- btrees (6.5)
- catboost (1.2.10)
- cffi (2.1.1)
- cvxopt (1.3.3)
- cython (3.3.0)
- ddtrace (4.15.0)
- dlib (20.0.1)
- ethos_u_vela (5.2.0)
- glpk (0.4.8)
- gmpy2 (2.3.1)
- igraph (1.0.0)
- instanttensor (0.2.0)
- kuzu (0.11.3)
- ladybug (0.20.4)
- lxml (6.1.3)
- mercurial (7.2.4)
- minorminer (0.2.22)
- mmcif (1.1.1)
- nanobind (3.0.1)
- ncnn (1.0.20260526)
- ntgcalls (2.2.5)
- numba (0.67.0)
- numpy (2.5.3)
- onnxoptimizer (0.4.2)
- open_spiel (2.0.2)
- opencc (1.4.2)
- opentimelineio (0.18.1)
- orjson (3.12.0)
- pandas (3.0.5)
- passagemath_combinat (10.8.11)
- passagemath_modules (10.8.11)
- passagemath_standard_no_symbolics (10.8.11)
- pillow (12.3.0)
- polyscope (2.6.1)
- praat_parselmouth (0.4.7)
- protovalidate (2.0.0)
- pybind11 (3.1.0)
- pybind11_global (3.1.0)
- pycuda (2026.1)
- pydemumble (0.1.3)
- pyfastx (2.3.1)
- pygame (2.6.1)
- pygame_ce (2.5.8)
- pyglm (2.8.3)
- pyicu (2.16.2)
- pymatching (2.4.0)
- pyodbc (5.3.0)
- pyopencl (2026.1.4)
- pyqt5_sip (12.19.0)
- pyrsistent (0.20.0)
- pysimdjson (7.0.2)
- pysqlite3 (0.6.0)
- pytensor (3.3.2)
- pywhispercpp (1.5.1)
- pywinpty (3.0.5)
- real_ladybug (0.15.3)
- recordclass (0.24.1)
- regex (2026.9.10)
- rhino3dm (8.35.0)
- sip (6.16.1)
- sqlcipher3 (0.6.2)
- sqlcipher3_wheels (0.5.7)
- sqlean_py (3.50.4.5)
- stpyv8 (13.1.201.22)
- symusic (0.6.0)
- ur_rtde (1.6.5)
- viennarna (2.7.2)
- winrt_windows_devices_enumeration (3.2.1)
- winrt_windows_foundation (3.2.1)
- winsdk-1.0.0b10
- wxpython (4.3.1)
- xatlas (0.0.11)
That's a long list of projects. So I'm not sure that it's a good idea to break them if we can continue to maintain PySlice_GetIndicesEx(). But I would prefer to keep the deprecation.
Can we do something to reduce the list of affected projects?
Activity
serhiy-storchaka commentedon Sep 24, 2026
The
PySlice_GetIndicesEx()function was redefined as aPySlice_GetIndicesEx()macro, which is safe to use (because it is a macro, andlengthis calculated after callingPySlice_Unpack()with other arguments). If projects do not define Py_LIMITED_API or define it >= 0x03060100, they are safe and do not need to change their code.pythongh-158077: Remove deprecated PySlice_GetIndicesEx() function
vstinner commentedon Sep 24, 2026
Oh, I didn't recall the complex situation of this function. Hum.
I don't think that it has to be that complicated. I propose to remove the deprecated and unsafe function implementation, leave a static inline function implementation, and remove the deprecation. The C API would not be affected.
I created PR gh-158089 to do that.
vstinner commentedon Sep 24, 2026
PySlice_GetIndicesEx()function was reimplemented as a macro by commit b2a5be0 from issue gh-72054.Py_DEPRECATED(3.7)was only added later, by commit 3c8724f.gvanrossum commentedon Sep 24, 2026
Try opening issues or PRs to the most commonly-used projects on the list. (IIRC Hugo maintains a list of PyPI projects by popularity.)