Hi Everyone, I’m still trying to write a plugin in order to integrate import linter into pants. I’m almost there, but I’m struggling with the path resolution. So I would like to setup the PYTHONPATH in PexProcess using extra_env parameter. How can I get the list of the my pants roots directory so I can set it up in the environment of my linter ?

process_result = await Get(
        FallibleProcessResult,
        PexProcess(
            importlinter_pex,
            argv=[],
            description="Running ImportLinter Playbook...",
            input_digest=merged_digest,
            level=LogLevel.DEBUG,
            extra_env={"PYTHONPATH": ":".join(pythonpath)},
            cache_scope=ProcessCacheScope.PER_RESTART_SUCCESSFUL,
        ),
    )

Hi! Rather than

PYTHONPATH

, you'll use

PEX_EXTRA_SYS_PATH

. First use

PythonSourceFiles

to determine the source roots you should set: https://github.com/pantsbuild/pants/blob/7e97ef6dfd50a8eb0294b6ded5e67dbd7da921df/src/python/pants/backend/python/lint/pylint/rules.py#L98 Then set the env like this: https://github.com/pantsbuild/pants/blob/7e97ef6dfd50a8eb0294b6ded5e67dbd7da921df/src/python/pants/backend/python/lint/pylint/rules.py#L164

I’m using the version 2.9 and it seems a lot of code in order to get the Targets with dependencies, there is no simpler way ?

Version of Pants shouldn't matter here. Pylint was maybe a bad example because it does fancy stuff with partitioning the input. Pytest is simpler There should be 3 steps: 1. `TransitiveTargets`: https://github.com/pantsbuild/pants/blob/7e97ef6dfd50a8eb0294b6ded5e67dbd7da921df/src/python/pants/backend/python/goals/pytest_runner.py#L164 2.

PythonSourceFiles

to get the source roots + the source files. Use this rather than

SourceFiles

or

HydratedSources

. https://github.com/pantsbuild/pants/blob/7e97ef6dfd50a8eb0294b6ded5e67dbd7da921df/src/python/pants/backend/python/goals/pytest_runner.py#L187 3. The

env={"PEX_EXTRA_SYS_PATH": }

line

Done and it works 😄 Thanks a lot