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debugging some strange behavior with a virtualenv ...
# general
s
debugging some strange behavior with a virtualenv created using 
./pants export --symlink-python-virtualenv
🧵
in our repo, we have to 
export PYTHONPATH=${REPO_ROOT}/src
to use 
python
directly / to run scripts in the virtualenv
when using the symlinked venv, I’m seeing that 
PYTHONPATH
is present in 
os.environ
, but it’s not updating 
sys.path
- only when running one of our custom binaries. the binary uses 
importlib
to dynamically import other modules in our source, and this is failing with `ModuleNotFoundError`s
I’m able to import the modules if I drop into a REPL with 
python
in the same venv
the custom binary is hacky AF so I am wondering if it’s a problem there, or if pants/pex are doing something when generating the venv such that 
PYTHONPATH
ends up getting stripped from the env in certain cases
e
Have you read the script shebangs?
s
I have not 🙂 you mean the shebang for the script having problems?
e
Yes
I'm allowing you the pleasure of finding things out.
s
oho
E
passed to 
python
e
Exactly
PEX == hermetic
So, you'll need to 
PYTHONPATH=x venv/bin/python venv/bin/script
as things stand for that script.
It may make sense to add an option to the venv PEX_TOOL to be sloppy and not add -sE
s
hmmm yeah - this does seem to make the symlink-export case less useful. same problem bites 
pylint
when it tries to load first-party plugins
granted we’d want people to 
./pants lint
instead of running 
pylint
directly, but trying to be flexible during the transition period 🤔
is https://github.com/pantsbuild/pex/blob/632a6ba3867d520e2721bf70fa1e7f114050c78b/pex/venv/pex.py#L98-L110 the right neighborhood for me to be reading through to grok the way things work now?
e
s
opened https://github.com/pantsbuild/pex/issues/2004 - if you’re 👍 to the idea, I can take a crack at the implementation
e
Thanks, SGTM.
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