coverage.exceptions.DataError: Can't combine statement coverage data with branch data

[ThomasWaldmann]

Describe the bug
I just transferred .coveragerc settings to pyproject.toml and CI broke with that error.

borgbackup/borg#8923

The only other change I made is that I installed coverage[toml] to make sure it also works on Python 3.10.

To Reproduce

1. What version of Python are you using? 3.11
2. What version of coverage.py shows the problem? 7.9.1

Expected behavior
It shouldn't matter whether settings are in .coveragerc or pyproject.toml.

[nedbat]

I agree it shouldn't matter where the settings are read from, and I believe it doesn't. People have been having trouble with pytest 8.4.0. Can you check to see if your pytest version differs between the good and bad runs?

[ThomasWaldmann]

I forced pytest < 8.4.0, but that didn't help: https://github.com/borgbackup/borg/actions/runs/15684663098/job/44184714512?pr=8923

pytest-cov also had recent new releases, will downgrade that as next try...

[ThomasWaldmann]

Forced pytest-cov < 6.2.0, didn't help either: https://github.com/borgbackup/borg/actions/runs/15684986322/job/44185800655?pr=8923#step:8:3851

Will downgrade coverage next... (update: that also didn't help)

[ThomasWaldmann]

Oops, I just noticed that my pytest command still had --cov-config=.coveragerc for pytest-cov.

Sorry, guess that was my fault...

[ThomasWaldmann]

Yeah, that was the root cause, closing.

Maybe this ticket can be at least helpful if someone else makes the same mistake and can find it here...