Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Properly strip source root prefixes for V2 Pytest runner #8185



Copy link

commented Aug 19, 2019


#7696 introduced support for source roots to V2 Pytest for the first time, but it did not support loose files. #8063 tried to fix this by no longer stripping the source root from source files. However, this caused two issues:

  1. Regression that repr() now shows the full path, not the relativized path: #8063 (comment)
  2. Namespace packages, such as contrib code, do not work with V2. A namespace package is where multiple folders have the same package name, like pants, but may not within the same actual folder.
    • Contrib unit tests would fail because PYTHONPATH had two entries referring to pants: src/python/pants and contrib/mypy/src/python/pants. Python would use whichever entry came first and ignore the other, which does not work. Instead, we want those two to merge into one namespace package.


Follow the V1 Pytest approach of stripping the source root, like we used to, but only for source files. Loose files (i.e. files()) are not stripped so that the file system APIs work as expected. This approach comes from:

def get_chroot_path(relpath: str) -> str:
if type(tgt) == Files:
# Loose `Files`, as opposed to `Resources` or `PythonTarget`s, have no (implied) package
# structure and so we chroot them relative to the build root so that they can be accessed
# via the normal Python filesystem APIs just as they would be accessed outside the
# chrooted environment. NB: This requires we mark the pex as not zip safe so
# these `Files` can still be accessed in the context of a built pex distribution. = False
return relpath
return str(Path(relpath).relative_to(tgt.target_base))


V2 Pytest now supports both source roots and loose files! This allows us to run most contrib unit tests with V2 and unblocks #8113.

Because over 95% of unit tests are now remoted, we go back to only one CI shard for unit tests.

Copy link

left a comment

Thanks a lot!

@Eric-Arellano Eric-Arellano force-pushed the Eric-Arellano:actually-handle-source-roots branch 2 times, most recently from 3725188 to a42ed86 Aug 20, 2019

@Eric-Arellano Eric-Arellano force-pushed the Eric-Arellano:actually-handle-source-roots branch from a42ed86 to 8d1e46b Aug 20, 2019

@stuhood stuhood force-pushed the Eric-Arellano:actually-handle-source-roots branch from 8d1e46b to ce918da Aug 20, 2019


This comment has been minimized.

Copy link

commented Aug 20, 2019

Your bootstrap shards raced another PR landing. Have rebased.


This comment has been minimized.

Copy link

commented Aug 20, 2019

There appear to be some actual failures in CI.

@Eric-Arellano Eric-Arellano force-pushed the Eric-Arellano:actually-handle-source-roots branch from ce918da to b464557 Aug 24, 2019


This comment has been minimized.

Copy link
Contributor Author

commented Aug 24, 2019

b464557 fixes the unit test failure. Test discovery was failing for test_coursier_resolve because the side-effects of importing psutil.tests caused unittest.TestCase to have __init__() defined, meaning that Pytest would no longer discover the targets.

Very unclear why this was not happening with V1 test runner or V2 before this change..not going to spend more time trying to answer that, though.

@Eric-Arellano Eric-Arellano merged commit 538b976 into pantsbuild:master Aug 25, 2019

1 check passed

continuous-integration/travis-ci/pr The Travis CI build passed

@Eric-Arellano Eric-Arellano deleted the Eric-Arellano:actually-handle-source-roots branch Aug 25, 2019

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
None yet
2 participants
You can’t perform that action at this time.