This issue tracks implementation of PEP 652.

CPython's Limited C-API and Stable ABI, introduced in PEP 384, will be formalized in a single definitive file, tested, and documented.

New changeset 92eebf6dd20c541ca5883d010a575fb6ea4a245c by Petr Viktorin in branch 'master':
bpo-43795: Sort PC/python3dll.c (GH-25312)
https://github.com/python/cpython/commit/92eebf6dd20c541ca5883d010a575fb6ea4a245c

Opened as a separate issue: bpo-43868, Remove PyOS_ReadlineFunctionPointer from the stable ABI list

I unsure about the following symbols.
Victor, do you think they should be part of the stable ABI?

 - PyThreadState_DeleteCurrent
 - Py_GetArgcArgv
 - PyInterpreterState_GetID

> PyThreadState_DeleteCurrent

No.

bpo-37878 explicitly excluded it from the limited C API. IMO it's too close to the CPython implementation and so must not be added to the stable ABI.

> Py_GetArgcArgv

No.

Python 3.10 now provides sys.orig_argv which can be read in C.
https://docs.python.org/dev/library/sys.html#sys.orig_argv

Py_GetArgcArgv() is part of the "legacy" C API to initialize Python. The "new" PyConfig API provides PyConfig.orig_argv.

FYI in the PyPI top 4000 projects, the function seems to be called by the following projects:

2021-02-18/uWSGI-2.0.19.1.tar.gz
2021-02-18/stem-1.8.0.tar.gz
2021-02-18/sphinx-gallery-0.8.2.tar.gz
2021-02-18/setproctitle-1.2.2.tar.gz
2021-02-18/pyuwsgi-2.0.19.1.post0.tar.gz
2021-02-18/mercurial-5.7.tar.gz
2021-02-18/httpretty-1.0.5.tar.gz
2021-02-18/CherryPy-18.6.0.tar.gz
2021-02-18/aws-encryption-sdk-cli-2.1.0.tar.gz

> PyInterpreterState_GetID

Yes.

It's part of the limited C API. IMO technically, it's ok to add to the stable ABI. I added it to PC/python3dll.c on purpose. Sadly, it's not available on PyPy, but I don't think that the stable ABI must care about PyPy which is a different use case.

Thanks! I'll send PRs later.

Thanks for linking to the issues/documentation!

I see that Py_GetArgcArgv it was exported in python3.def (i.e. stable ABI) in bpo-40910, which got backported to 3.9.

And the removal of PyThreadState_DeleteCurrent was reverted: bpo-38266

While we would like to deprecate/remove them in the future, they are now part of the stable ABI.
They are now in internal headers, so I will exclude them from the limited API.

Should we mention PEP 652 in Include/README.rst, now that the PEP is accepted?

> Should we mention PEP 652 in Include/README.rst, now that the PEP is accepted?

No, we should link to the documentation (when it's written). The PEP is a design document; it'll become outdated.

New changeset e7cc64e297001cc79b9afab80f71d9e6d1267cb7 by Petr Viktorin in branch 'master':
bpo-43795: PEP-652: Simplify headers for easier static analysis (GH-25483)
https://github.com/python/cpython/commit/e7cc64e297001cc79b9afab80f71d9e6d1267cb7

New changeset 9d6a2d0ee7e55402656e1dec46400591b62db331 by Petr Viktorin in branch 'master':
bpo-43795: PEP-652: Clean up the stable ABI/limited API (GH-25482)
https://github.com/python/cpython/commit/9d6a2d0ee7e55402656e1dec46400591b62db331

Right now, running "make regen-limited-abi" adds again functions which were removed from Doc/data/stable_abi.dat:
https://github.com/python/cpython/pull/25687#issuecomment-828520575

diff --git a/Doc/data/stable_abi.dat b/Doc/data/stable_abi.dat
index cdc7160250..6fe61743d6 100644
--- a/Doc/data/stable_abi.dat
+++ b/Doc/data/stable_abi.dat
@@ -351,11 +351,17 @@ PyMapping_Length
 PyMapping_SetItemString
 PyMapping_Size
 PyMapping_Values
+PyMarshal_ReadObjectFromString
+PyMarshal_WriteLongToFile
+PyMarshal_WriteObjectToFile
+PyMarshal_WriteObjectToString
 PyMem_Calloc
 PyMem_Free
 PyMem_Malloc
 PyMem_Realloc
 PyMemberDescr_Type
+PyMember_GetOne
+PyMember_SetOne
 PyMemoryView_FromMemory
 PyMemoryView_FromObject
 PyMemoryView_GetContiguous


I guess that you should not be added until this issue is solved.

I hope the PR fixes that. I plan to merge tomorrow if there ar no objections to it.

On April 28, 2021 5:15:19 PM GMT+02:00, STINNER Victor <report@bugs.python.org> wrote:
>
>STINNER Victor <vstinner@python.org> added the comment:
>
>Right now, running "make regen-limited-abi" adds again functions which
>were removed from Doc/data/stable_abi.dat:
>https://github.com/python/cpython/pull/25687#issuecomment-828520575
>
>diff --git a/Doc/data/stable_abi.dat b/Doc/data/stable_abi.dat
>index cdc7160250..6fe61743d6 100644
>--- a/Doc/data/stable_abi.dat
>+++ b/Doc/data/stable_abi.dat
>@@ -351,11 +351,17 @@ PyMapping_Length
> PyMapping_SetItemString
> PyMapping_Size
> PyMapping_Values
>+PyMarshal_ReadObjectFromString
>+PyMarshal_WriteLongToFile
>+PyMarshal_WriteObjectToFile
>+PyMarshal_WriteObjectToString
> PyMem_Calloc
> PyMem_Free
> PyMem_Malloc
> PyMem_Realloc
> PyMemberDescr_Type
>+PyMember_GetOne
>+PyMember_SetOne
> PyMemoryView_FromMemory
> PyMemoryView_FromObject
> PyMemoryView_GetContiguous
>
>
>I guess that you should not be added until this issue is solved.
>
>----------
>
>_______________________________________
>Python tracker <report@bugs.python.org>
><https://bugs.python.org/issue43795>
>_______________________________________

New changeset f6ee4dad589c0953283dacb577a2d808fda7aae9 by Petr Viktorin in branch 'master':
bpo-43795: Generate python3dll.c and doc data from manifest (PEP 652) (GH-25315)
https://github.com/python/cpython/commit/f6ee4dad589c0953283dacb577a2d808fda7aae9

New changeset 8f3ef457ad286e73f272dadec8b98d2ea3a6ec72 by Miss Islington (bot) in branch '3.10':
bpo-43795: Mark PyCodec_Unregister as a function, not data, in stable ABI (GH-25920)
https://github.com/python/cpython/commit/8f3ef457ad286e73f272dadec8b98d2ea3a6ec72

Unfortunately commit b05955d6f5f149523b5855a335444b7c6324bdb7 has broken all refleak buildbots:

https://buildbot.python.org/all/#/builders/259/builds/25/steps/5/logs/stdio

See example:

----------------------------------------------------------------------
Ran 53 tests in 5.629s
OK (skipped=1)
......
test_tools leaked [251, 251, 251] references, sum=753
test_tools leaked [91, 91, 91] memory blocks, sum=273
1 test failed again:
    test_tools

Per our buildbot policy, it will be reverted if is not fixed in 24h to avoid masking other errors.

Thanks for the note!

This is due to `csv`. Adding a script in Tools/scripts that imports csv will also make the refleak check fail.
I'll investigate further.

I opened https://bugs.python.org/issue44116 for the leak when trying to unload _csv.
Looks like investigating that will take a while, so I'll send a small PR to unblock the buildbots.

New changeset 373937182ee029c282bea58cdda57ab41990f404 by Miss Islington (bot) in branch '3.10':
bpo-43795: PEP 652 user documentation (GH-25668) (GH-26034)
https://github.com/python/cpython/commit/373937182ee029c282bea58cdda57ab41990f404

New changeset 68b9c20a98887bf0a92698f8df9f28b9440970dc by Miss Islington (bot) in branch '3.10':
bpo-43795: Remove Py_FrozenMain from the Limited API & Stable ABI  (GH-26241) (GH-26353)
https://github.com/python/cpython/commit/68b9c20a98887bf0a92698f8df9f28b9440970dc

New changeset 257e400a19b34c7da6e2aa500d80b54e4c4dbf6f by Petr Viktorin in branch 'main':
bpo-43795: Note Stable ABI PEP in What's New (GH-26479)
https://github.com/python/cpython/commit/257e400a19b34c7da6e2aa500d80b54e4c4dbf6f

New changeset 75185561a9a3b6dede3ad87bd83bab66847bd425 by Miss Islington (bot) in branch '3.10':
bpo-43795: Note Stable ABI PEP in What's New (GH-26479) (GH-26603)
https://github.com/python/cpython/commit/75185561a9a3b6dede3ad87bd83bab66847bd425

New changeset 7cad9cb51bdae2144cbab330f13a607ba3471742 by Petr Viktorin in branch 'main':
bpo-43795: Don't list private names in the limited API (GH-26740)
https://github.com/python/cpython/commit/7cad9cb51bdae2144cbab330f13a607ba3471742

New changeset 7fd40101b7130016fc98f05ce34746fed68ab542 by Miss Islington (bot) in branch '3.10':
bpo-43795: Don't list private names in the limited API (GH-26740)
https://github.com/python/cpython/commit/7fd40101b7130016fc98f05ce34746fed68ab542

New changeset 276468dddb46c54980c782c09cdb53bd90755752 by Petr Viktorin in branch 'main':
bpo-43795: Add a test for Stable ABI symbol availability using ctypes (GH-26354)
https://github.com/python/cpython/commit/276468dddb46c54980c782c09cdb53bd90755752

New changeset 98e506ae8a7997658a08fbf77ac016d200588cb3 by Petr Viktorin in branch 'main':
bpo-43795: Document stable_abi.txt format and contents (GH-29956)
https://github.com/python/cpython/commit/98e506ae8a7997658a08fbf77ac016d200588cb3