Pytest on python3.6-dbg aborts when passed `--durations` flag.

[charris]

Both pytest 5.0.1 and 5.1.0 error on python3.6-dbg when the --durations flag is used.

====================================================== slowest 10 test durations =======================================================
python3.6: ../Objects/unicodeobject.c:9486: _PyUnicode_InsertThousandsGrouping: Assertion `0 <= min_width' failed.
Fatal Python error: Aborted

Current thread 0x00007f5f733dc0c0 (most recent call first):
  File "/home/charris/.local/lib/python3.6/site-packages/_pytest/runner.py", line 59 in pytest_terminal_summary
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 81 in <lambda>
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 87 in _hookexec
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/hooks.py", line 289 in __call__
  File "/home/charris/.local/lib/python3.6/site-packages/_pytest/terminal.py", line 661 in pytest_sessionfinish
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/callers.py", line 203 in _multicall
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 81 in <lambda>
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 87 in _hookexec
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/hooks.py", line 289 in __call__
  File "/home/charris/.local/lib/python3.6/site-packages/_pytest/main.py", line 221 in wrap_session
  File "/home/charris/.local/lib/python3.6/site-packages/_pytest/main.py", line 228 in pytest_cmdline_main
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/callers.py", line 187 in _multicall
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 81 in <lambda>
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/manager.py", line 87 in _hookexec
  File "/home/charris/.local/lib/python3.6/site-packages/pluggy/hooks.py", line 289 in __call__
  File "/home/charris/.local/lib/python3.6/site-packages/_pytest/config/__init__.py", line 77 in main
  File "/home/charris/Workspace/numpy.git/build/testenv/lib/python3.6/site-packages/numpy/_pytesttester.py", line 205 in __call__
  File "runtests.py", line 297 in main
  File "runtests.py", line 491 in <module>
Aborted (core dumped)

• a detailed description of the bug or suggestion
• output of pip list from the virtual environment you are using
• pytest and operating system versions
• minimal example if possible

[charris]

This seems to be a Python bug, see https://bugs.python.org/issue35560 ? They didn't backport the fix to 3.6, unfortunately. Maybe the format statement that causes the problem can be tweaked?

[asottile]

here's the line fwiw:

pytest/src/_pytest/runner.py

Line 59 in 3076522

tr.write_line("{:02.2f}s {:<8} {}".format(rep.duration, rep.when, rep.nodeid))

[charris]

Looks like Python isn't going to fix this for 3.6, so the choice is to live with it or find some format tweak that won't trigger it. I have no idea exactly what part of the format is causing problems.

[nicoddemus]

@charris if you want to tweak the line yourself until the problem disappears we would be happy to merge a PR with the fix.

[symonk]

It appears this was eventually backported to python3.6 via python/cpython#23231 tho it might take a while to filter through, @nicoddemus i'm provisionally closing this, hope that is OK.

python/cpython@dae5d72

[nicoddemus]

hope that is OK.

Sure thing, thanks for that!