Apart from porting test_xpickle, a resource was also added in libregrtest's command line options (as this was originally available in Py2 but removed in Py3, and the test takes considerably long).

I have tested the code against Windows 10 and Ubuntu 20.04. It is also compatible with the py launcher in Windows (PEP 397). In total, it takes around 14 minutes to run the entire test on Ubuntu 20.04, which isn't all that surprising considering the Py2 tests took a few minutes to run, and pickletester has added many more test functions since then.

Compatible versions to bounce pickles from are Python 3.6 - 3.9. Supporting Python 3.5 wasn't feasible since the pickletester library has to be imported, and it has generous use of f-strings.

This is my first time contributing to CPython, and I'd really like feedback on how I can improve this PR, thanks!

https://bugs.python.org/issue31391

Issue:Forward-port test_xpickle from 2.7 to 3.x #75572

Fidget-Spinner added2 commits

September 29, 2020 23:17

Forward-port test_xpickle from Python 2 to 3.

c55fec1

remove staticmethod decorators, silence errors

edd799d

the-knights-who-say-ni added the CLA signed label

Sep 29, 2020

bedevere-bot added the awaiting review label

Sep 29, 2020

make patchcheck

2dc67fe

iritkatriel reviewed

Sep 29, 2020

View reviewed changes

Lib/test/test_xpickle.py OutdatedShow resolvedHide resolved

Implement some suggestions by iritkatriel

c463dec

Copy link

MemberAuthor

Fidget-Spinner commentedSep 30, 2020

@iritkatriel , thanks for the really thorough review, I have implemented most of the suggestions

Merge remote-tracking branch 'upstream/master' into add_test_xpickle

5c962fb

zware mentioned this pull request

May 3, 2022

Forward-port test_xpickle from 2.7 to 3.x#75572

Open

ezio-melotti removed the CLA signed label

Jul 13, 2022

Merge branch 'main' into add_test_xpickle

ac914d9

AlexWaygood changed the title~~bpo-31391: Forward-port test_xpickle from Python 2 to 3.~~gh-75572: Forward-port test_xpickle from Python 2 to 3.

Apr 28, 2023

Copy link

python-cla-botbot commentedApr 18, 2025•
edited
Loading

All commit authors signed the Contributor License Agreement.

serhiy-storchaka added2 commits

January 3, 2026 15:05

Merge branch 'main' into add_test_xpickle

dd2cd6b

Fix compatibility.

7ba3de8

Copy link

Member

serhiy-storchaka commentedJan 3, 2026

Thank you for your PR,@Fidget-Spinner. This is a great work, especially for the first contribution (you contributed after this a lot, and it was valuable contribution). Unfortunately, the PR became slightly outdated, and new conflicts were introduced.

I resolved conflicts and fixed other incompatibilities:

Python tests no longer use test_main(). The tests should be generated inload_tests().
test.support no longer compatible with older Python versions. I fixed some errors, but currently it only work in 3.8 and newer. It is possible to make it working in 3.7 at the cost of getting rid of positional-only parameters, but is more difficult to go further.
Some new tests which test pickling all builtins need corrections.

We perhaps can make more tests supporting by moving some code to separate files, but the current version is already great.

serhiy-storchaka added6 commits

January 3, 2026 20:27

Fix test_inheritance_pep563.

0b06350

Use subprocess.DEVNULL.

0604d9d

Simplify highest_proto_for_py_version().

5a28b4d

Get rid of pathlib.

1ab1203

Partially support 3.5.

7101adb

Only share tested classes. Full support of 3.5+.

8a23399

Copy link

Member

serhiy-storchaka commentedJan 3, 2026

By moving the testing classes to a separate module I managed to fix support for 3.5+. Only this module is shared between versions, so we have no restrictions to uise new syntax in tests.

serhiy-storchaka added6 commits

January 3, 2026 22:49

Clean up xpickle_worker.py.

d482988

Fix test_pickle. Enable more tests in test_xpickle.

c00dbc2

Enable more tests.

66a19ef

Use enterClassContext().

3c75f48

Support Python 3.2+.

f4758a4

Fix lint error.

d027d77

serhiy-storchaka added2 commits

January 4, 2026 18:09

Silence lint warning.

5401703

Support Python 2.7.

21e5130

serhiy-storchaka added tests

Tests in the Lib/test dir

needs backport to 3.13

bugs and security fixes

needs backport to 3.14bugs and security fixes labels

Jan 5, 2026

serhiy-storchaka added5 commits

January 6, 2026 10:10

Fix RuntimeWarning in 2.7.

1f7038c

Add more explicit skips.

552f358

Merge branch 'main' into add_test_xpickle

30819fe

Merge branch 'main' into add_test_xpickle

fb5d9f6

Merge branch 'main' into add_test_xpickle

7705b3b

serhiy-storchaka merged commit8735daf intopython:main

Jan 6, 2026

55 checks passed

Copy link

miss-islington-appbot commentedJan 6, 2026

Thanks@Fidget-Spinner for the PR, and@serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14.
🐍🍒⛏🤖

bedevere-appbot removed the awaiting review label

Jan 6, 2026

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request

Jan 6, 2026

pythongh-75572: Forward-port test_xpickle from Python 2 to 3 (pythonG…

ea5528f

…H-22452)Move data classes used in tests to separate file test_picklecommon.py,so it can be imported in old Python versions.(cherry picked from commit8735daf)Co-authored-by: Ken Jin <kenjin@python.org>Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Copy link

miss-islington-appbot commentedJan 6, 2026

Sorry,@Fidget-Spinner and@serhiy-storchaka, I could not cleanly backport this to3.13 due to a conflict.
Please backport usingcherry_picker on command line.

cherry_picker 8735daf3e82d50defd791e9be7b9ae6843bc4ed1 3.13

miss-islington-appbot assignedserhiy-storchaka

Jan 6, 2026

Copy link

bedevere-appbot commentedJan 6, 2026

GH-143485 is a backport of this pull request to the3.14 branch.

bedevere-appbot removed the needs backport to 3.14bugs and security fixes label

Jan 6, 2026

serhiy-storchaka added a commit that referenced this pull request

Jan 6, 2026

[3.14]gh-75572: Forward-port test_xpickle from Python 2 to 3 (GH-22452…

9812845

…) (GH-143485)Move data classes used in tests to separate file test_picklecommon.py,so it can be imported in old Python versions.(cherry picked from commit8735daf)Co-authored-by: Ken Jin <kenjin@python.org>Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

serhiy-storchaka added a commit to serhiy-storchaka/cpython that referenced this pull request

Jan 7, 2026

[3.13]pythongh-75572: Forward-port test_xpickle from Python 2 to 3 (p…

f7c1280

…ythonGH-22452)Move data classes used in tests to separate file test_picklecommon.py,so it can be imported in old Python versions.(cherry picked from commit8735daf)Co-authored-by: Ken Jin <kenjin@python.org>Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

serhiy-storchaka added a commit to serhiy-storchaka/cpython that referenced this pull request

Jan 7, 2026

[3.13]pythongh-75572: Forward-port test_xpickle from Python 2 to 3 (p…

2446b42

…ythonGH-22452)Move data classes used in tests to separate file test_picklecommon.py,so it can be imported in old Python versions.(cherry picked from commit8735daf)(cherry picked from commitff0a8b7)Co-authored-by: Ken Jin <kenjin@python.org>Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Copy link

bedevere-appbot commentedJan 7, 2026

GH-143509 is a backport of this pull request to the3.13 branch.

bedevere-appbot removed the needs backport to 3.13bugs and security fixes label

Jan 7, 2026

serhiy-storchaka added a commit that referenced this pull request

Jan 7, 2026

[3.13]gh-75572: Forward-port test_xpickle from Python 2 to 3 (GH-22452…

d030847

…) (GH-143509)Move data classes used in tests to separate file test_picklecommon.py,so it can be imported in old Python versions.(cherry picked from commit8735daf)(cherry picked from commitff0a8b7)Co-authored-by: Ken Jin <kenjin@python.org>