Does pants isolate tests from the current user?

[wfscheper]

Hey all,

I'm running into a strange problem with adopting pants for an existing set of python projects. One of my core libraries imports gitpython, and I just started getting an import error in my test suite when that package is loaded:

src/python/library/file.py:32: in <module>
    import git
/Users/myuser/.cache/pants/named_caches/pex_root/venvs/8bd9e33500432545844f939d30ad1bf95e01e3e8/5297058c8463f8ff9040f549c7fb2b0cef2dcd50/lib/python3.8/site-packages/git/__init__.py:89: in <module>
    raise ImportError('Failed to initialize: {0}'.format(exc)) from exc
E   ImportError: Failed to initialize: Cmd('git') failed due to: exit code(128)
E     cmdline: git version
E     stderr: 'error: could not expand include path '~/.gitcinclude'
E   fatal: bad config line 44 in file /usr/local/git/etc/gitconfig'

If I run /Users/myuser/.cache/pants/named_caches/pex_root/venvs/8bd9e33500432545844f939d30ad1bf95e01e3e8/5297058c8463f8ff9040f549c7fb2b0cef2dcd50/bin/python -c 'import git', I do not get the import error.

I stepped through the import with pdb, and eventually gitpython is simply running git in a subprocess. This makes me wonder if pants is doing something so that ~ is not resolvable by git during the test run?

For anyone coming to this later, a temporary workaround is to comment out the line including ~/.gitinclude. However, this file is maintained by homebrew, so I don't consider this a long-term solution to the problem.

pants is version 2.6.0
OS is macOS 11.6
python is 3.8.12

[jsirois]

Pants does isolate tests as much as possible from the local environment. By default, this includes not exposing HOME; so an inability to expand ~ seems to make sense. You can selectively expose environment variables to tests: https://www.pantsbuild.org/docs/python-test-goal#setting-environment-variables and you can also expose them more broadly: https://www.pantsbuild.org/docs/reference-subprocess-environment.

I'd suggest trying the following in your pants.toml to start since its the most narrowly scoped leak of hermeticity:

[test]
extra_env_vars = ["HOME"]

[wfscheper]

That makes sense. Thanks for the doc pointer!

[jsirois]

You're welcome. Keep in mind that exposing HOME to tests means that when you enable remote caching, tests will have to re-run for every user since they'll all have a different HOME (presumably) and will thus miss the cache.