GitHub Actions: Test on Python 3.14

[cclauss]

Python 3.14 (the π version)
https://www.python.org/downloads/release/python-3140/
https://github.com/actions/python-versions/releases

• https://docs.python.org/3.14/whatsnew/3.14.html#porting-to-python-3-14
  • https://docs.python.org/3.14/whatsnew/3.14.html#pickle

If you encounter NameErrors or pickling errors coming out of multiprocessing or concurrent.futures, see the forkserver restrictions.

Pwntools Pull Request

Thanks for contributing to Pwntools! Take a moment to look at CONTRIBUTING.md to make sure you're familiar with Pwntools development.

Please provide a high-level explanation of what this pull request is for.

Testing

Pull Requests that introduce new code should try to add doctests for that code. See TESTING.md for more information.

Target Branch

Depending on what the PR is for, it needs to target a different branch.

You can always change the branch after you create the PR if it's against the wrong branch.

Branch	Type of PR
dev	New features, and enhancements
dev	Documentation fixes and new tests
stable	Bug fixes that affect the current stable branch
beta	Bug fixes that affect the current beta branch, but not stable
dev	Bug fixes for code that has never been released

Changelog

After creating your Pull Request, please add and push a commit that updates the changelog for the appropriate branch.
You can look at the existing changelog for examples of how to do this.

[peace-maker]

The remaining issues are about itertools not being serialisable anymore in 3.14. We'll have to change the implementation of the relevant functions to not use a deep copy etc.

python/cpython#101588

@Arusekk mentioned #1665 needed similar treatment when multiprocessing changed the default start method on macos.

This came to Linux now too. python/cpython#84559

[cclauss]

• https://docs.python.org/3.14/whatsnew/3.14.html#porting-to-python-3-14
  • https://docs.python.org/3.14/whatsnew/3.14.html#pickle

If you encounter NameErrors or pickling errors coming out of multiprocessing or concurrent.futures, see the forkserver restrictions.

[Arusekk]

I almost got it, I decided to augment pickle with marshal for mbruteforce. This will also be a better fix for the original macOS issue, hopefully.

As for iters.lookahead, I think we can just drop it? It seems that it was broken (inefficient, wrong edge case handling) right from the start, as the Python issue says. Just a single function, no internal uses, and supposedly little uses outside (not many comments or links to that issue).

[cclauss]

Rock and roll! 🚀