gh-144748: Document 3.12 and 3.14 changes to PyErr_CheckSignals

[ZeroIntensity]

I'll need to remove the reference to the remote debugger in the 3.13 backport.

• Issue: PEP 475 EINTR retry paths don't check tstate->async_exc #144748

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📚 Documentation preview 📚: https://cpython-previews--144982.org.readthedocs.build/en/144982/c-api/exceptions.html#c.PyErr_CheckSignals

[encukou]

My suggestion didn't apply well, sorry.
I pushed to your branch directly. Does this look good?

[ZeroIntensity]

We might want to note that neither the GC nor debugger scripts can raise an exception here. Otherwise, this looks good.

[encukou]

Can you think of a situation where this info would be helpful?

Situations I can think of look best solved by if (PyErr_Occurred()) PyErr_WriteUnraisable, rather than avoiding individual sources of possible exceptions.

[ZeroIntensity]

I was thinking about assertions, e.g. assert(PyErr_CheckSignals() == 0), but maybe that's too far-fetched.

[encukou]

Yeah, I don't think you should ever do that.

[ZeroIntensity]

Ok, let's go with this.

[miss-islington-app]

Thanks @ZeroIntensity for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-145062 is a backport of this pull request to the 3.14 branch.

[bedevere-app]

GH-145063 is a backport of this pull request to the 3.13 branch.