I think the mypy plugin needs a feature flag to control whet Pants #general

I think the mypy plugin needs a feature flag to co...

gentle-flower-25372

03/28/2024, 5:26 AM

I think the mypy plugin needs a feature flag to control whether it adds all of the source roots to MYPYPATH or kicks off one mypy run per source root. I found these two threads which hit the same issue I have. https://pantsbuild.slack.com/archives/C046T6T9U/p1671746311585759 https://pantsbuild.slack.com/archives/C046T6T9U/p1671746224355039 For context; I am adopting pants in a python monorepo. Before pants we built, tested, linted all packages individually. So our conflicting test sub-dir module-a/{module_a,test} and module-b/{module_b,test} wasn't an issue. Now pants is pulling in and shoving all of the source roots into MYPYPATH which is causing mypy to throw the following error:

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error: Duplicate module named 'test'

I've attempted to use the mypy ignore option without success. I realize that moving around the test sub-dir to something unique per module would fix this or moving tests next to the source, but both of those options aren't ideal when talking about adopting pants into over 100 modules. This is the culprit: https://github.com/pantsbuild/pants/blob/1d1e93edcdf617c651c3eb1d1cbadd29d99172b2/src/python/pants/backend/python/typecheck/mypy/rules.py#L338

gentle-flower-25372

03/28/2024, 5:41 AM

I tried doing this and it doesn't work either because it's still pulling in dependent modules.

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pants --changed-since=origin/main list | grep pyproject.toml:poetry | sed 's|/pyproject.toml:poetry|::|g' | xargs pants check

gentle-flower-25372

03/28/2024, 6:03 AM

Workaround I came up with for now... 1. Install mypy via pipx 2. For loop over changed and call mypy directly

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set -e

for dir in $(pants --changed-since=origin/main list | egrep "pyproject.toml:poetry$" | sed 's|/pyproject.toml:poetry||g'); do
    pushd $dir
    mypy --config-file $(git rev-parse --show-toplevel)/mypy.ini .
    popd
done

dazzling-plastic-2448

03/28/2024, 7:37 PM

I would love something like this as well. Would solve a significant problem for us as well.

broad-processor-92400

03/31/2024, 12:49 AM

One possible approach to this would be https://github.com/pantsbuild/pants/issues/17739, where mypy invocations are partitioned by the config files that apply, and then one could indicate the separate invocations by having appropriate mypy configuration in ecah directory.

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