[C API] marshal.h must not use FILE* type in the limited C API

[vstinner]

BPO	45474
Nosy	@vstinner, @encukou, @miss-islington
PRs	bpo-45474: Fix the limited C API of marshal.h #28956 bpo-45474: Exclude all of marshal.h if Py_LIMITED_API is defined #29061

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2021-10-20.09:33:07.251>
created_at = <Date 2021-10-14.20:09:23.656>
labels = ['expert-C-API', '3.11']
title = '[C API] marshal.h must not use FILE* type in the limited C API'
updated_at = <Date 2021-10-20.09:33:07.250>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2021-10-20.09:33:07.250>
actor = 'petr.viktorin'
assignee = 'none'
closed = True
closed_date = <Date 2021-10-20.09:33:07.251>
closer = 'petr.viktorin'
components = ['C API']
creation = <Date 2021-10-14.20:09:23.656>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 45474
keywords = ['patch']
message_count = 6.0
messages = ['403941', '403958', '403985', '403993', '404308', '404408']
nosy_count = 3.0
nosy_names = ['vstinner', 'petr.viktorin', 'miss-islington']
pr_nums = ['28956', '29061']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue45474'
versions = ['Python 3.11']

[vstinner]

Include/marshal.h defines 2 functions with FILE* argument in the limited C API, whereas the PEP-384 disallows that:

"In addition, functions expecting FILE* are not part of the ABI, to avoid depending on a specific version of the Microsoft C runtime DLL on Windows."
https://www.python.org/dev/peps/pep-0384/

PyAPI_FUNC(void) PyMarshal_WriteLongToFile(long, FILE *, int);
PyAPI_FUNC(void) PyMarshal_WriteObjectToFile(PyObject *, FILE *, int);

I propose to exclude these functions from the limited C API.

Hopefully, they are not part of the documented stable ABI.

[vstinner]

New changeset af1083e by Victor Stinner in branch 'main':
bpo-45474: Fix the limited C API of marshal.h (GH-28956)
af1083e

[encukou]

Just note that these were *not* part of the limited API, which is defined in Misc/stable_abi.txt rather than the #ifdefs: https://docs.python.org/3.10/c-api/stable.html#stable
If they were, the functions would need to remain in the stable ABI.

[vstinner]

Petr:

Just note that these were *not* part of the limited API, which is defined in Misc/stable_abi.txt rather than the #ifdefs: https://docs.python.org/3.10/c-api/stable.html#stable
If they were, the functions would need to remain in the stable ABI.

Thanks for double checking. I wasn't sure ;-)
#28956 (comment)

[encukou]

Nothing from marshal.h is part of the limited API, and nothing from there is exported in the stable ABI DLL.
The entire file should be in #ifndef Py_LIMITED_API, rather than just a part.

[miss-islington]

New changeset 98fa3b5 by Petr Viktorin in branch 'main':
bpo-45474: Exclude all of marshal.h if Py_LIMITED_API is defined (GH-29061)
98fa3b5