Make Trio's excepthook play nicely with Ubuntu's excepthook

[njsmith]

Fixes gh-1065

[codecov]

Codecov Report

Merging #1528 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1528   +/-   ##
=======================================
  Coverage   99.67%   99.67%           
=======================================
  Files         107      108    +1     
  Lines       13308    13331   +23     
  Branches     1010     1011    +1     
=======================================
+ Hits        13265    13288   +23     
  Misses         28       28           
  Partials       15       15           

Impacted Files	Coverage Δ
trio/_core/_multierror.py	100.00% <100.00%> (ø)
trio/_core/tests/test_multierror.py	100.00% <100.00%> (ø)
...tests/test_multierror_scripts/apport_excepthook.py	100.00% <100.00%> (ø)

[pquentin]

I failed to reproduce the issue in Docker using Ubuntu and trio from PyPI. I think you're using Ubuntu locally, is this reproducing for you?

I also tried not installing python-apport in ci.sh and the tests still passed: see pquentin@ebcde15 and https://github.com/pquentin/trio/actions/runs/107173872

[pquentin]

Hmm I managed to reproduce it, looks like it only happens outside of virtual environments. But in ci.sh we use a virtual environment?

Maybe none of this matters, I don't know.

[njsmith]

Yeah, the original issue only affects the system python, so sudo pip install trio or pip install --user trio, with no venv, on Ubuntu, with python3-apport installed.

The test is marked to be skipped if you don't have Ubuntu + python3-apport, and then inside the test it does a gross hack to make a venv python temporarily act like a system python. The change to ci.sh to install python3-apport is technically redundant because it turns out the images already have it installed, but I guess it's still good for documentation and robustness?

[pquentin]

Thanks, that makes sense!