gh-140550: Initial implementation of PEP 793 – PyModExport by encukou · Pull Request #140556 · python/cpython

encukou · 2025-10-24T16:18:03Z

This adds the initial implementation of PEP-793.
See the issue for follow-up tasks.

Issue: Implement PEP 793 – PyModExport #140550

This uses a "def-like" structure: a PyModuleDef* that's not a valid Python object.

encukou

Thank you for the initial review!

Yes, but there's a lot of tests. And I've also renamed things that changed semantics, so unrelated changes/backports will conflict or fail to build, rather than merge cleanly at the Git level but be subtly broken.

encukou · 2025-10-28T17:16:50Z

+import unittest
+import types


I couldn't find this in PEP 8.

encukou · 2025-10-28T17:37:57Z

!buildbot AMD64.FreeBSD.Refleaks

bedevere-bot · 2025-10-28T17:38:00Z

🤖 New build scheduled with the buildbot fleet by @encukou for commit 01d52ba 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F140556%2Fmerge

The command will test the builders whose names match following regular expression: AMD64.FreeBSD.Refleaks

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AMD64 FreeBSD Refleaks PR

encukou · 2025-10-29T08:07:27Z

Do you plan to add documentation in a separated PR?

Yes. There's a lot to add since the PEP calls for soft-deprecation of PyInit_; see the issue.

Co-authored-by: Kumar Aditya <kumaraditya@python.org>

vstinner

LGTM. Just please move _PyModule_GetGCHooks() to pycore_moduleobject.h.

vstinner · 2025-11-04T10:17:06Z

+static inline PyModuleDef *_PyModule_GetDefOrNull(PyObject *arg) {
+ PyModuleObject *mod = _PyModule_CAST(arg);
+ if (mod->md_token_is_def) {
+ return (PyModuleDef *)((PyModuleObject *)mod)->md_token;


Suggested change
return (PyModuleDef*)((PyModuleObject*)mod)->md_token;
return (PyModuleDef*)mod->md_token;

vstinner · 2025-11-04T10:26:38Z


 PyMODINIT_FUNC
-FUNC_NAME(MODULE_NAME)(void)
+INITFUNC_NAME(MODULE_NAME)(void)


Is it really needed to define a PyInit function if a modexport function is defined with slots? Developers may reuse this code as an example.

Thanks for the catch! I think I had some platform-specific issues with the current version of setuptools. I added this to the TODO list in the issue; I'll get to it in a later PR.

encukou · 2025-11-05T11:31:18Z

Thank you for the review!

vstinner · 2025-11-05T12:59:01Z

Congrats :-)

vstinner · 2025-11-05T16:51:02Z

make check-limited-abi does now fail on the main branch:

./python -E ./Tools/build/generate-build-details.py `cat pybuilddir.txt`/build-details.json
Checked 115 modules (37 built-in, 77 shared, 1 n/a on linux-x86_64, 0 disabled, 0 missing, 0 failed on import)
./python ./Tools/build/stable_abi.py --all
File /home/vstinner/python/main/Doc/data/stable_abi.dat differs from expected!
--- /home/vstinner/python/main/Doc/data/stable_abi.dat
+++ <expected>
@@ -979,14 +979,6 @@
type,Py_buffer,3.11,,full-abi
type,Py_intptr_t,3.2,,
macro,Py_mod_abi,3.15,,
-macro,Py_mod_doc,3.15,,
-macro,Py_mod_methods,3.15,,
-macro,Py_mod_name,3.15,,
-macro,Py_mod_state_clear,3.15,,
-macro,Py_mod_state_free,3.15,,
-macro,Py_mod_state_size,3.15,,
-macro,Py_mod_state_traverse,3.15,,
-macro,Py_mod_token,3.15,,
macro,Py_mp_ass_subscript,3.2,,
macro,Py_mp_length,3.2,,
macro,Py_mp_subscript,3.2,,

I created #141056 to fix the issue.

encukou · 2025-11-05T17:02:20Z

Thank you!

…honGH-140556) Co-authored-by: Victor Stinner <vstinner@python.org> Co-authored-by: Kumar Aditya <kumaraditya@python.org>

encukou added 30 commits October 24, 2025 17:01

Define PyMODEXPORT_FUNC
4ad95be

Add new state to module object
c53650d

Make sure the module def matches the state
9564e20

Add simple test case
05a87c3

Add new slot definitions
57c4f1e

Modules are bigger sue me
956c59a

Add a test for PyModule_FromSlotsAndSpec
14a66d2

Add PyModule_FromSlotsAndSpec (empty for now)
72a27f5

Add module test
b54293b

Fill in enough of a PyModuleDef to pass to common machinery
fcc68f8

Pass in a spec
3ab607e

Rename field which can now be NULL
35d7d51

Common implementation for PyModule_From{Def,Slots}AndSpec
6fbbc18
This uses a "def-like" structure: a PyModuleDef* that's not a valid Python object.

Add test for Py_mod_name slot
7207e07

Handle Py_mod_name
8d4d264

Test repeated slot
bd61e5b

Test Py_mod_name with a def
d638abf

Py_mod_doc
b24e6a6

Disallow NULL slot value
756cbff

Test repeats and NULL for all new slots
320de14

Add PyModule_GetSize
4d88cf3

Test size
a1d3c15

Handle size
7fcee67

Test new slots with PyModuleDef
9fd1e7e

Py_mod_methods
fd95984

GC hooks
748e18f

Py_mod_token
1101f55

Py_mod_exec
488eae7

Clean up slot-handling a bit
f9d0dde

Py_mod_create
020dcc6

encukou commented Oct 28, 2025
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vstinner reviewed Oct 28, 2025
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Comment threadObjects/moduleobject.c Outdated

encukou added 2 commits October 29, 2025 09:02

Correct logic
ba6e602

Merge in the main branch
d26e9b7

kumaraditya303 reviewed Nov 2, 2025
View reviewed changes

Comment threadInclude/internal/pycore_moduleobject.h Outdated

kumaraditya303 reviewed Nov 2, 2025
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Comment threadInclude/internal/pycore_moduleobject.h Outdated

kumaraditya303 reviewed Nov 2, 2025
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Comment threadInclude/internal/pycore_moduleobject.h Outdated

encukouand others added 2 commits November 3, 2025 14:52

Get the spaces just right
26b57f2
Co-authored-by: Kumar Aditya <kumaraditya@python.org>

Merge branch 'main' into modexport-rebased
66e8309

kumaraditya303 reviewed Nov 3, 2025
View reviewed changes

Comment threadPython/import.c Outdated

_PyModule_GetDefOrNull never raises
928f23b

vstinner approved these changes Nov 4, 2025
View reviewed changes

bedevere-appBot added awaiting merge and removed awaiting core review labels Nov 4, 2025

encukouand others added 4 commits November 4, 2025 12:52

Merge in the main branch
4f3712f

Remove _PyModule_GetGCHooks; get the hooks directly via internal API
55ae793

Style fixes
1e6b18c

Remove unused variables
4d58846

encukou merged commit 589a03a into python:mainNov 5, 2025
46 checks passed

bedevere-appBot removed the awaiting merge label Nov 5, 2025

encukou deleted the modexport-rebased branch November 5, 2025 11:31

ngoldbaum mentioned this pull request Jan 15, 2026
PyModule_FromSlotsAndSpec and PyModule_GetToken exposed without named parameters #143883
Closed

	return (PyModuleDef)((PyModuleObject)mod)->md_token;
	return (PyModuleDef*)mod->md_token;

		import unittest
		import types

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encukou commented Oct 24, 2025•
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