Add exceptiongroup support to third party projects

[agronholm]

As requested on python-trio/trio#2213, we should try to add exceptiongroup support to both IPython and Apport. This issue tracks all efforts to add exceptiongroup support to other projects.

IPython seems to use customized versions of format_exception() and format_exception_only(), so it's likely to need an update to display exception groups, even on Python 3.11.

Apport, on the other hand, uses format_exc() and print_exc() straight from the traceback module, so a conditional import might do the trick.

[agronholm]

As of 1.0.0rc9, other projects can now be made to support exception group formatting via this library.

[henryiii]

Is pytest such a library?

[agronholm]

I believe there are people already working to integrate exception groups to pytest.

[renefritze]

The hypothesis project had a number of PRs concerning the topic.

[henryiii]

The tip:

For now, you can use pytest's --tb=native flag to see the tracebacks for each sub-exception.

looks to be very useful for now. Ideally PyTest will start displaying exception groups and notes natively at some point.

[Zac-HD]

Linking all the ecosystem issues and status I know of, so they're visible in one place:

• Hypothesis since version 6.54.0 (2022-08-02), Switch from MultipleFailures to PEP-654 ExceptionGroup HypothesisWorks/hypothesis#3308
• Pytest since version 7.2.0 (2022-10-23), fallback to native traceback when handling ExceptionGroup (take 2) [SQUASH] pytest-dev/pytest#10209
• IPython since version 8.15 (2023-09-01), fall back to native when printing an ExceptionGroup ipython/ipython#14108
• Pycharm Trio and PyCharm fighting over sys.excepthook python-trio/trio#1553
• Rich [REQUEST] Support for PEP 654 tracebacks (ExceptionGroups) Textualize/rich#1859, proposed fix in ExceptionGroup PEP654 proof of concept. Textualize/rich#3033
• Apport looks like we'd report a bug to https://bugs.launchpad.net/apport and open a PR at https://github.com/canonical/apport; see Apport ExeptHook detection stopped working. python-trio/trio#2464 for links to Trio's current workaround
  • Given the length of Ubuntu support cycles, the only way to avoid breaking their users might be to carry a workaround in exceptiongroup until Python 3.10 reaches end of life in October 2026.

[jakkdl]

@agronholm are you okay with adding/moving the apport excepthook we currently have in Trio over to exceptiongroup? I can report a bug and open PR in apport for adding exceptiongroup support, but as Zac above says exceptiongroup would also need to carry a workaround due to Ubuntu being very conservative in package versions and new apport releases would take approximately forever to trickle down to all end users.

[agronholm]

I'm okay with it as a workaround, so long as it doesn't affect anything else.

[jakkdl]

Apport looks like we'd report a bug to https://bugs.launchpad.net/apport and open a PR at https://github.com/canonical/apport; see python-trio/trio#2464 for links to Trio's current workaround

As of #88 there is now a workaround for apport, but I also opened https://bugs.launchpad.net/apport/+bug/2042672