PEP 3121, 384 Refactoring applied to xxsubtype module

[RobinSchreiber]

BPO	15848
Nosy	@abalkin, @vstinner
Files	xxsubtype_pep3121-384_v0.patch

^{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 2020-12-18.00:47:20.540>
created_at = <Date 2012-09-02.14:29:27.256>
labels = ['extension-modules', 'performance']
title = 'PEP 3121, 384 Refactoring applied to xxsubtype module'
updated_at = <Date 2020-12-18.00:47:20.539>
user = 'https://bugs.python.org/RobinSchreiber'

bugs.python.org fields:

activity = <Date 2020-12-18.00:47:20.539>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2020-12-18.00:47:20.540>
closer = 'vstinner'
components = ['Extension Modules']
creation = <Date 2012-09-02.14:29:27.256>
creator = 'Robin.Schreiber'
dependencies = []
files = ['27097']
hgrepos = []
issue_num = 15848
keywords = ['pep3121']
message_count = 4.0
messages = ['169701', '170069', '372082', '383281']
nosy_count = 3.0
nosy_names = ['belopolsky', 'vstinner', 'Robin.Schreiber']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'resource usage'
url = 'https://bugs.python.org/issue15848'
versions = ['Python 3.4']

[RobinSchreiber]

Changes proposed in PEP-3121 and PEP-384 have now been applied to the xxsubtype module!

[abalkin]

It looks like your patch will result in reference leaks if type creation fails. I think you should add Py_DECREF(m) before error returns.

[vstinner]

The PEP-3121 part is fixed by:

commit d5cacbb
Author: Nick Coghlan <ncoghlan@gmail.com>
Date: Sat May 23 22:24:10 2015 +1000

PEP-489: Multi-phase extension module initialization

Known limitations of the current implementation:

- documentation changes are incomplete
- there's a reference leak I haven't tracked down yet

The leak is most visible by running:

  ./python -m test -R3:3 test_importlib

However, you can also see it by running:

  ./python -X showrefcount

Importing the array or _testmultiphase modules, and
then deleting them from both sys.modules and the local
namespace shows significant increases in the total
number of active references each cycle. By contrast,
with _testcapi (which continues to use single-phase
initialisation) the global refcounts stabilise after
a couple of cycles.

[vstinner]

See bpo-41111 "[C API] Convert a few stdlib extensions to the limited C API (PEP-384)" for the PEP-384 part.