👍 in principle.

When I get a little more time this will come with a proper description and email to dev mailing list.

Please consider moving the config to somewhere else than pyproject.toml (possible per twisted/towncrier#127), as that triggers specific pip behavior that's broken on some setups (pypa/pip#5317).

I can chime in to say that we've been doing this on dateutil and setuptools for some time now and it has been a major improvement in the workflow, at the cost of asking contributors to do a little more work ahead of time. A few things I would suggest:

1. pip has a bot set up that automatically detects whether the news file is missing and requests that users add it if so. I recommend doing something similar.
2. pip also has something set up with "stub" files for trivial changes that don't require a changelog. If you don't think your PR needs a changelog, you add an empty changelog file with the .trivial.rst ending to satisfy the bot. I've been considering using this. Another alternative is the way CPython does it, which is a label "Skip News" that core devs can apply to satisfy the bot.

One last thing to note is that I believe towncrier was developed for Twisted, which has a workflow that requires some slightly different matching between tickets and PRs. As a result, I find it somewhat annoying that my one-off PRs tend to require two commits (or at least two pushes), because I need to use the PR number in the stub for the issue. I have also occasionally had more than one PR for a single issue ticket in the same class, and I always forget how to work around that (if it's even possible). I don't find these annoying enough to not use towncrier, but it may be worth considering.

Please consider moving the config to somewhere else than pyproject.toml (possible per hawkowl/towncrier#127), as that triggers specific pip behavior that's broken on some setups (pypa/pip#5317).

I think it would be slightly better to add PEP 517 support for matplotlib (i.e. add a pyproject.toml file for the purpose it was intended). The biggest downsides I see to doing this are 1. installable edits will not use PEP 517 yet (it will fall back to the normal installation mode) and 2. pip does all PEP 517 builds in an isolated environment, which means you won't get any benefits from cached, incremental builds, which can be very annoying for big builds.

Not sure where the issue for tracking problem 2 is, but if it's a deal-breaker it's probably worth letting the pip developers know that, since eventually PEP 517 will be the only supported installation mechanism for pip, and this "opt-in" period is really to try and surface problems before they become major headaches for anyone.

I am all ears if you have a better suggestion as to how to better report 2) edit: the problem with install.user and pyproject.toml that I'm linking above, given that I opened the issue more than a year ago on the pip tracker, the issue has seen little activity, and at least from my personal POV it's definitely a blocker...

Please consider moving the config to somewhere else than pyproject.toml (possible per hawkowl/towncrier#127), as that triggers specific pip behavior that's broken on some setups (pypa/pip#5317).

@anntzer I've followed the links, and as far as I can tell this only works when calling towncrier from python (and not on the command line), am I missing something?

From https://github.com/hawkowl/towncrier/pull/127/files#diff-8495d47e3a84a0fc5cdb51fd186aafc4R25 you should just be able to call towncrier --pyproject=towncrier.toml (or whatever you call it)?

As discussed briefly on the call, it'd be nice if this was run during CI (however, that is done) so PR authors can see what this looks like...

I see you added a test entry. Where does the Changelog get rendered?

I see you added a test entry. Where does the Changelog get rendered?

I haven't worked out how to not use pyproject.toml yet, so doing the rendering is pending

Perhaps you can manually migrate a couple of currently existing whatsnews to changelog/ to make it easier to test this manually?

That's not the blocker, I don't think it's possible to have a custom towncrier config file at the moment, but I'm submitting a PR upstream to towncrier to fix that.

Ah, I see.
I would much prefer not using pyproject.toml (per the above), but if that turns out to be too complicated, I don't want to block the PR over that either.

So that we do not do all the work double. I have pinged the twisted mailing list about moving along towncrier, I hope that happens fairly soon. If not, I may indeed vendor a patched version into numpy (the pyproject.toml file is currently not my primary concern, but it may still come up and would be nice).

For reference this is waiting on twisted/towncrier#157 to go in to towncrier

Closing in favour of #15158