pants fmt sometimes ignoring pyproject.toml?

[ryanking]

Describe the bug
I think that pants is sometimes ignoring our pyproject.toml file, specifically tool.isort.known_first_party.

Pants version

$ ./pants version
2.8.0

OS
MacOS

Additional info

When running fmt across he whole repo, I have to use xargs to chunk the files due to #13462. When I do that, pants seems to ignore our config and reformat imports which are in known_first_party. My coworker on Linux, which has a higher MAX_ARGS and therefore does not need xargs does not see this problem.

$ ./pants list src/:: --list-sep="\0" | xargs -n1000 -0 ./pants fmt 
<snip>
Fixing src/util/tests/test_tee.py
Fixing src/util/tests/test_tokens.py
Fixing src/util/testutil.py
Fixing src/util/text_mailer.py
Fixing src/util/usps.py



+ Black made changes.
+ isort made changes.
+ shfmt made changes.

(there should be no changes to isort, black and shfmt expected)

However, when I run ./pants fmt directly on the targets in question it works fine:

$ ./pants fmt src/util/
15:47:58.83 [INFO] Completed: Format with Black - Black made no changes.
All done! ✨ 🍰 ✨
66 files left unchanged.


15:47:59.62 [INFO] Completed: Format with isort - isort made no changes.

✓ Black made no changes.
✓ isort made no changes.

It seems that all (or almost all) the changes I find are modules listed in known_first_party being shuffled.

[Eric-Arellano]

Hey @ryanking sorry for the delay, slower responses than normal with the holidays. I wonder if you've seen this tip? https://www.pantsbuild.org/docs/python-linters-and-formatters#isort-possible-issues-with-its-import-classifier-algorithm

You're note alone with isort 5's import classifier algorithm not playing well with Pants, and that was a problem for pantsbuild/pants itself.

To confirm that Pants is indeed picking up pyproject.toml, you can use --no-process-execution-local-cleanup (called --no-process-cleanup in 2.9+): https://www.pantsbuild.org/docs/troubleshooting#debug-tip-inspect-the-sandbox-with---no-process-execution-local-cleanup

[Eric-Arellano]

Hey Ryan, is this still happening?

[ryanking]

I think we have this all resolved now.