My package Foo builds an extension libFoo.so that depends on another package Bar's extension libBar.so, and I don't know a priori where the dependency libBar.so is already installed. I need to know the dependency's directory in order to set libFoo.so's rpath so that it can find libBar.so at runtime.
I thought a good way to do this might be to import the dependency package Bar in my setup.py and inspect the module to get the directory, since I know where libBar.so will be relative to the Bar package's directory. That way if they installed from a virtual environment, I would locate the appropriate path.
However, when I try to do this, i.e., when I activate a virtual environment and install my package from PyPI, I find that import Bar in the setup.py ends up importing a version from a DIFFERENT virtual environment (I can tell by inspecting the built libFoo.so's rpath after installation).
On the other hand, if I install the Foo package locally by navigating to the source directory and doing pip install -e . with my virtual environment activated, the rpath is set correctly...
How can I get the right behavior when installing from PyPI? In case it helps, here is the relevant code from setup.py:
import Bar
barDir = os.path.dirname(inspect.getfile(Bar))
When I activate my environment and install from PyPI, barDir is
/Users/me/anaconda/envs/WRONGENVIRONMENT/lib/python2.7/site-packages/bar
When I activate my environment and install locally, barDir is
/Users/me/anaconda/envs/RIGHTENVIRONMENT/lib/python2.7/site-packages/bar
I'm running OS X 10.10.5 and using conda environments
It turned out to be a stupid caching problem (pip install was not getting the latest package from PyPI, but using a cached copy of an older version I had been testing with). I had to do
pip install --no-cache-dir Foo
to ensure I was getting a fresh version