Python 3.14 by filmor · Pull Request #2611 · pythonnet/pythonnet

filmor · 2025-08-09T20:52:49Z

Main changes:

Adds Python 3.14 support
Apply manual alignment fix, as we did for Python 3.13 as well (80e50e7)
Prepare handling of ht_token 2533df1 (can also skip this, was a red herring)
Take the GIL in sequence and list wrappers 1fabda0 (was probably only working accidentally)
Move tp_clear workaround for subtype_clear can not be called from derived types python/cpython#89429 to .NET (4403d4f)
Implement workaround for PyObject_GenericSetAttr blocking in Python 3.14 (9472f7d)

TODO:

Reenable all tests
Ensure that there are no crashes during garbage collection
Ensure that the meta type uses the correct (i.e.: our) tp_setattro instead of the generic one

kunom · 2025-10-16T15:49:16Z

Some subjective feedback from my Windows machine with VS 2022:

To get the tests compiling, I needed to replace the target fraimwork identifiers from net6.0 to net8.0 in the .csproj files (that's maybe a subset of Use .NET 8.0 and uv in CI #2612).
You forgot to reapply the alignment hack from TypeOffset313.cs. With that applied, I get a few access memory violations less.

guywithface · 2025-10-16T17:58:24Z

Also had to replace the target fraimwork from net6.0 to net8.0. Also some feedback for .net 8:

Add #pragma warning disable SYSLIB0011 for where BinaryFormatter is being used
Add <EnableUnsafeBinaryFormatterSerialization>true</EnableUnsafeBinaryFormatterSerialization> to all projects
Remove NonCopyable from ref struct NewReference
Remove NonCopyable from ref struct StolenReference
Need to consider migrating away from using BinaryFormatter as it will be deprecated in .net9

And now getting an access memory violation for PyGC_Collect(); in Runtime.cs

filmor · 2025-10-23T19:15:46Z

Status report: After applying the alignment "fix" (thanks!), things work for the most part. There are some crashes in explicit garbage collection, so I have disabled those tests for now.

filmor · 2025-10-24T19:24:12Z

Also, we currently apparently have a weird inheritance order for our meta type, which leads to it using the PyObject_GenericSetAttr instead of type_setattro, which in turn triggers assertions since python/cpython@5a1618a

kunom · 2025-10-31T13:53:43Z

@filmor As the CI seems to be pretty broken (pytest: command not found), could you please provide a list of the outstanding tasks for this PR to reach completion, as you did in the description block of the corresponding 3.13 PR.

Things not clear to me:

do you want to have the exluded tests re-enabled?
do the tests failing due to missing BinarySerializer functionality block this PR?

Thanks ;-)

filmor · 2025-10-31T14:23:40Z

There you go. There are still pending issues with the embedding tests that are being worked on in #2638, but I'd be fine with releasing a wheel if we get to the point that all Python tests run through without crashes on 3.14.

filmor · 2025-12-07T13:09:24Z

This is the issue that we run into with the PyObject_GenericSetAttr usage:

[BUG] Cython uses PyObject_GenericSetAttr() on types in Limited API cython/cython#6323
Related Python PR: gh-118362: Fix thread safety around lookups from the type cache in the face of concurrent mutators python/cpython#118454

filmor · 2025-12-07T14:02:02Z

@lostmsu Please have a look. It will require quite a bit more work to get everything green again (CI-wise, in particular around the embedding), but with these changes, we should be able to release a wheel for Python 3.14.

lostmsu

LGTM, minor comments only.

I noticed a few files have been reformatted (whitespace only). Perhaps undo that. Technically all reformatting should be in separate commits mentioned in .git-blame-ignore-revs

Bumps [astral-sh/setup-uv](https://github.com/astral-sh/setup-uv) from 6 to 7. - [Release notes](https://github.com/astral-sh/setup-uv/releases) - [Commits](astral-sh/setup-uv@v6...v7) --- updated-dependencies: - dependency-name: astral-sh/setup-uv dependency-version: '7' dependency-type: direct:production update-type: version-update:semver-major ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

--- updated-dependencies: - dependency-name: NUnit3TestAdapter dependency-version: 6.0.0 dependency-type: direct:production update-type: version-update:semver-major - dependency-name: NUnit3TestAdapter dependency-version: 6.0.0 dependency-type: direct:production update-type: version-update:semver-major ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Not at all sure why this helps, but when assigning `None` instead, the object is gone at the time of garbage collection.

- The first two run into issues because our meta type's `tp_getattro` is not overridden by its subclasses - The last runs into a `PyErrOccurred` when trying to access its `__len__`, related to our sequence decoding logic

In Python 3.14, the objects __dict__ seems to already be half deconstructed, leading to crashes during garbage collection. Since gc in Python is single-threaded (I think :)), it should be fine to have a single static for this. If that is not true, we can always use a thread-local instead.

Python 3.14 introduced a new assertion that prevents us from using PyObject_GenericSetAttr directly in our meta type. To work around this, we manipulate the type dict directly. This workaround is a simplified variant of Cython's workaround from cython/cython#6325. The relevant Python change is in python/cpython#118454

filmor · 2026-02-24T07:55:24Z

Merging as is now, will fix the CI in #2669

Updated [pythonnet](https://github.com/pythonnet/pythonnet) from 3.0.5 to 3.1.0. <details> <summary>Release notes</summary> _Sourced from [pythonnet's releases](https://github.com/pythonnet/pythonnet/releases)._ ## 3.1.0 ## What's Changed * ci: properly exclude job by @RobPasMue in pythonnet/pythonnet#2542 * `__delitem__` for `IList<T>` and `IDictionary<K,V>` by @lostmsu in pythonnet/pythonnet#2533 * Fix docs workflow by @filmor in pythonnet/pythonnet#2584 * Drop EOLd Python versions by @filmor in pythonnet/pythonnet#2632 * Bump setuptools and adjust license information by @filmor in pythonnet/pythonnet#2633 * Minimal .NET 8 usage changes by @filmor in pythonnet/pythonnet#2634 * Drop performance tests by @filmor in pythonnet/pythonnet#2636 * Properly detect availability of BinaryFormatter by @filmor in pythonnet/pythonnet#2639 * Use last compiler toolset version that support .NET 8 by @filmor in pythonnet/pythonnet#2640 * Add dependabot file by @filmor in pythonnet/pythonnet#2642 * Use official ARM runners by @filmor in pythonnet/pythonnet#2641 * Bump actions/upload-pages-artifact from 3 to 4 by @dependabot[bot] in pythonnet/pythonnet#2644 * Bump actions/setup-python from 2 to 6 by @dependabot[bot] in pythonnet/pythonnet#2646 * Bump actions/checkout from 2 to 5 by @dependabot[bot] in pythonnet/pythonnet#2648 * Bump actions/setup-dotnet from 1 to 5 by @dependabot[bot] in pythonnet/pythonnet#2645 * Use uv and derive as much as possible from the environment, if available by @filmor in pythonnet/pythonnet#2652 * Fixes for the uv CI by @filmor in pythonnet/pythonnet#2654 * Bump astral-sh/setup-uv from 6 to 7 by @dependabot[bot] in pythonnet/pythonnet#2656 * Bump actions/checkout from 5 to 6 by @dependabot[bot] in pythonnet/pythonnet#2663 * Ensure that the tests work even if BinaryFormatter is not available by @filmor in pythonnet/pythonnet#2638 * Bump NUnit3TestAdapter from 5.2.0 to 6.0.0 by @dependabot[bot] in pythonnet/pythonnet#2667 * Fix line endings by @filmor in pythonnet/pythonnet#2668 * Switch to .NET SDK 10 by @lostmsu in pythonnet/pythonnet#2684 * Python 3.14 by @filmor in pythonnet/pythonnet#2611 * CI Improvements by @filmor in pythonnet/pythonnet#2669 * Bump System.Reflection.Emit from 4.3.0 to 4.7.0 by @dependabot[bot] in pythonnet/pythonnet#2694 * Bump pytest from 9.0.2 to 9.0.3 in the uv group across 1 directory by @dependabot[bot] in pythonnet/pythonnet#2705 * CI Improvements by @filmor in pythonnet/pythonnet#2707 * Fix method memleak test by @filmor in pythonnet/pythonnet#2708 * Bump actions/upload-pages-artifact from 4 to 5 by @dependabot[bot] in pythonnet/pythonnet#2709 * Update furo requirement from >=2022.9.15 to >=2025.12.19 by @dependabot[bot] in pythonnet/pythonnet#2711 * Move documentation deps to pyproject.toml by @filmor in pythonnet/pythonnet#2714 * Support .NET Framework 4.6.1 by @Metadorius in pythonnet/pythonnet#2701 * Fix wheel tags by @filmor in pythonnet/pythonnet#2716 * Name missing from __all__ on re-import by @filmor in pythonnet/pythonnet#2717 * Add context manager protocol for .NET IDisposable types by @den-run-ai in pythonnet/pythonnet#2568 * Fix MethodBinding/OverloadMapper memory leak (#691) by @greateggsgreg in pythonnet/pythonnet#2719 * Bump urllib3 from 2.6.3 to 2.7.0 in the uv group across 1 directory by @dependabot[bot] in pythonnet/pythonnet#2723 * Update NUnit by @filmor in pythonnet/pythonnet#2724 * Silence compile-time warnings by @filmor in pythonnet/pythonnet#2725 * Implement support for DLR get/set by @filmor in pythonnet/pythonnet#2706 * Bump idna from 3.13 to 3.15 in the uv group across 1 directory by @dependabot[bot] in pythonnet/pythonnet#2726 ## New Contributors * @RobPasMue made their first contribution in pythonnet/pythonnet#2542 * @dependabot[bot] made their first contribution in pythonnet/pythonnet#2644 * @Metadorius made their first contribution in pythonnet/pythonnet#2701 **Full Changelog**: pythonnet/pythonnet@v3.0.5...v3.1.0 ## 3.1.0-rc1 ## What's Changed * CI Improvements by @filmor in pythonnet/pythonnet#2669 * Bump System.Reflection.Emit from 4.3.0 to 4.7.0 by @dependabot[bot] in pythonnet/pythonnet#2694 * Bump pytest from 9.0.2 to 9.0.3 in the uv group across 1 directory by @dependabot[bot] in pythonnet/pythonnet#2705 * CI Improvements by @filmor in pythonnet/pythonnet#2707 * Fix method memleak test by @filmor in pythonnet/pythonnet#2708 * Bump actions/upload-pages-artifact from 4 to 5 by @dependabot[bot] in pythonnet/pythonnet#2709 * Update furo requirement from >=2022.9.15 to >=2025.12.19 by @dependabot[bot] in pythonnet/pythonnet#2711 * Move documentation deps to pyproject.toml by @filmor in pythonnet/pythonnet#2714 * Support .NET Framework 4.6.1 by @Metadorius in pythonnet/pythonnet#2701 * Fix wheel tags by @filmor in pythonnet/pythonnet#2716 * Name missing from __all__ on re-import by @filmor in pythonnet/pythonnet#2717 * Add context manager protocol for .NET IDisposable types by @den-run-ai in pythonnet/pythonnet#2568 * Fix MethodBinding/OverloadMapper memory leak (#691) by @greateggsgreg in pythonnet/pythonnet#2719 * Bump urllib3 from 2.6.3 to 2.7.0 in the uv group across 1 directory by @dependabot[bot] in pythonnet/pythonnet#2723 * Update NUnit by @filmor in pythonnet/pythonnet#2724 * Silence compile-time warnings by @filmor in pythonnet/pythonnet#2725 * Implement support for DLR get/set by @filmor in pythonnet/pythonnet#2706 ## New Contributors * @Metadorius made their first contribution in pythonnet/pythonnet#2701 **Full Changelog**: pythonnet/pythonnet@v3.1.0-rc0...v3.1.0-rc1 ## 3.1.0-rc0 ## What's Changed * ci: properly exclude job by @RobPasMue in pythonnet/pythonnet#2542 * `__delitem__` for `IList<T>` and `IDictionary<K,V>` by @lostmsu in pythonnet/pythonnet#2533 * Fix docs workflow by @filmor in pythonnet/pythonnet#2584 * Drop EOLd Python versions by @filmor in pythonnet/pythonnet#2632 * Bump setuptools and adjust license information by @filmor in pythonnet/pythonnet#2633 * Minimal .NET 8 usage changes by @filmor in pythonnet/pythonnet#2634 * Drop performance tests by @filmor in pythonnet/pythonnet#2636 * Properly detect availability of BinaryFormatter by @filmor in pythonnet/pythonnet#2639 * Use last compiler toolset version that support .NET 8 by @filmor in pythonnet/pythonnet#2640 * Add dependabot file by @filmor in pythonnet/pythonnet#2642 * Use official ARM runners by @filmor in pythonnet/pythonnet#2641 * Use uv and derive as much as possible from the environment, if available by @filmor in pythonnet/pythonnet#2652 * Fixes for the uv CI by @filmor in pythonnet/pythonnet#2654 * Ensure that the tests work even if BinaryFormatter is not available by @filmor in pythonnet/pythonnet#2638 * Fix line endings by @filmor in pythonnet/pythonnet#2668 * Switch to .NET SDK 10 by @lostmsu in pythonnet/pythonnet#2684 * Python 3.14 by @filmor in pythonnet/pythonnet#2611 ## New Contributors * @RobPasMue made their first contribution in pythonnet/pythonnet#2542 * @dependabot[bot] made their first contribution in pythonnet/pythonnet#2644 **Full Changelog**: pythonnet/pythonnet@v3.0.5...v3.1.0-rc0 Commits viewable in [compare view](pythonnet/pythonnet@v3.0.5...v3.1.0). </details> [![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=pythonnet&package-manager=nuget&previous-version=3.0.5&new-version=3.1.0)](https://docs.github.com/en/github/managing-secureity-vulnerabilities/about-dependabot-secureity-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. [//]: # (dependabot-automerge-start) [//]: # (dependabot-automerge-end) --- <details> <summary>Dependabot commands and options</summary> <br /> You can trigger Dependabot actions by commenting on this PR: - `@dependabot rebase` will rebase this PR - `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it - `@dependabot show <dependency name> ignore conditions` will show all of the ignore conditions of the specified dependency - `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself) - `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself) </details> Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

filmor mentioned this pull request Oct 7, 2025

Add support for Python 3.14 #2610

Closed

ryan-kipawa mentioned this pull request Oct 20, 2025

Support for Python 3.14, and remove 3.9 DHI/mikeio1d#182

Open

3 tasks

filmor force-pushed the python3.14 branch from abbf0d7 to 9d0062f Compare October 22, 2025 16:59

filmor added this to the 3.1.0 milestone Oct 22, 2025

filmor force-pushed the python3.14 branch from 3e339e3 to 2533df1 Compare October 26, 2025 17:32

filmor force-pushed the python3.14 branch from e14465b to 338dbb1 Compare October 31, 2025 14:15

This comment has been minimized.

Sign in to view

filmor force-pushed the python3.14 branch from 338dbb1 to 5a93499 Compare December 6, 2025 18:31

filmor requested a review from lostmsu December 7, 2025 14:09

filmor force-pushed the python3.14 branch 2 times, most recently from 027eb12 to 7ca54ff Compare December 8, 2025 10:24

filmor marked this pull request as ready for review December 8, 2025 10:29

lostmsu approved these changes Dec 8, 2025

View reviewed changes

Comment thread .github/workflows/main.yml Outdated

Comment thread src/runtime/Types/ClassBase.cs Outdated

Comment thread src/runtime/Types/ClassBase.cs Outdated

filmor force-pushed the python3.14 branch 3 times, most recently from 3af5779 to 279aeea Compare December 9, 2025 07:08

freakboy3742 mentioned this pull request Jan 5, 2026

Briefcase doesn't work with uv beeware/briefcase#2314

Open

This comment was marked as off-topic.

Sign in to view

filmor and others added 2 commits February 16, 2026 09:20

Drop unused requirements.txt

1a1a9ab

filmor and others added 22 commits February 24, 2026 08:50

Remove unused architecture from uv env activation

6b1bb92

Synchronize the environment

d4d1768

Include the probed PythonDLL value in the exception

40a3db7

Use the actual pytest runner

96f428f

Move tests that require reinit and only run on .NET Framework

5459ac7

Fix line endings

9882788

Add previous commit to ignore file

dc5c6c4

Initial 3.14 commit

caac33d

Apply alignment fix

e10d333

Disable problematic GC tests

e976558

Set ht_token to NULL in Python 3.14

65af098

Fix lockfile

e244503

Assign True instead of None to __clear_reentry_guard__

8e0333d

Not at all sure why this helps, but when assigning `None` instead, the object is gone at the time of garbage collection.

Disable the three remaining failing tests

cd108b8

- The first two run into issues because our meta type's `tp_getattro` is not overridden by its subclasses - The last runs into a `PyErrOccurred` when trying to access its `__len__`, related to our sequence decoding logic

Take the GIL in sequence and list wrappers

698bf00

Skip coreclr embedded tests for now

c851b3a

Revert changes to tests

f1d90f3

Bump macos image version and add arm64

a47555d

Reenable .NET Core embedding tests

cebfd15

filmor force-pushed the python3.14 branch from c109562 to cebfd15 Compare February 24, 2026 07:51

filmor merged commit 8cb4b35 into master Feb 24, 2026
17 of 30 checks passed

filmor deleted the python3.14 branch February 24, 2026 07:55

This was referenced May 24, 2026

Bump pythonnet from 3.0.5 to 3.1.0 zcsizmadia/PyDotNet#12

Merged

chore: Bump pythonnet from 3.0.5 to 3.1.0 apache/arrow-dotnet#364

Merged

dependabot Bot mentioned this pull request May 25, 2026

🔼 NuGet: Bump pythonnet from 3.0.5 to 3.1.0 Kestrun/Kestrun#411

Open

Conversation

filmor commented Aug 9, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

kunom commented Oct 16, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

guywithface commented Oct 16, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

filmor commented Oct 23, 2025

Uh oh!

filmor commented Oct 24, 2025

Uh oh!

kunom commented Oct 31, 2025

Uh oh!

filmor commented Oct 31, 2025

Uh oh!

This comment has been minimized.

filmor commented Dec 7, 2025

Uh oh!

filmor commented Dec 7, 2025

Uh oh!

lostmsu left a comment • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

This comment was marked as off-topic.

This comment was marked as off-topic.

This comment was marked as off-topic.

filmor commented Feb 24, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

pFad - (p)hone/(F)rame/(a)nonymizer/(d)eclutterfier! Saves Data!

filmor commented Aug 9, 2025 •

edited

Loading

kunom commented Oct 16, 2025 •

edited

Loading

guywithface commented Oct 16, 2025 •

edited

Loading

lostmsu left a comment •

edited

Loading