Loading pants.backend.codegen.protobuf.python fails in dev releases

[stuhood]

Somewhere between 2.0.0.dev2 and 2.0.0.dev4, loading pants.backend.codegen.protobuf.python from pants wheels in a dev release (see pantsbuild/example-python#26) began to fail.

Running from sources (with light edits to the pants_from_sources script) works fine, so it seems like something is potentially not packaged in the release wheel that should be.

[stuhood]

Braindumping a bit. The files includes in the release wheels and in the repository sources don't appear to show any differences (according to roughly find ~/src/pants/src/python -name '*.py' | sort -u > sources/files.txt and find /Users/stuhood/.cache/pants/setup/bootstrap-Darwin-x86_64/2.0.0.dev4_py36/lib/python3.6/site-packages/pants -name '*.py' | sort -u > binary/files.txt):

files.diff.txt

I haven't had any luck diffing the set of installed rules either (although that approach was a bit hackier). Will definitely need to further improve rule graph errors to better highlight what might be missing.

[stuhood]

So, I realized that I was not running from sources with precisely dev4. And sure enough, precisely dev4 fails when run from sources.

HEAD (e4b6476) works from sources. So it is actually possible that #10428 will prevent this moving forward.

I'll kick off another dev release.

[Eric-Arellano]

This happened in the Pants repo too. It was fixed by #10409. #10428 would have caught this proactively.