'pip install -r requirements.txt -t lib' does not work for namespaced packages

[webmaven]

It seems that pip installing namespace packages (examples: repoze.lru, zope.events, zope.interface, etc.) into a local directory like lib/ does not work. Or rather, the packages are installed correctly, but Python ignores the *-nspkg.pth file when packages are not in the usual locations: pypa/pip#1924

Right now, the skeleton inserts lib/ into sys.path to make dependencies importable in the first place: https://github.com/GoogleCloudPlatform/appengine-python-flask-skeleton/blob/master/appengine_config.py#L6

Is there anything similar that can be done to get namespace packages working correctly?

[webmaven]

Looks like replacing the sys.path.insert() call with site.addsitedir() is the right solution. Would a PR be accepted?

[proppy]

@webmaven, sure as long as you follow CONTRIB.md and document which version of pip is required in README.md.

[webmaven]

Thanks!

UPDATE: The version of pip required has not changed.

[webmaven]

BTW, I've submitted the individual CLA.

[lesv]

I'm reviewing this now. Sorry for the delay.

[webmaven]

@lesv, thanks for merging the PR! Should I close this issue now, and get started on similar issues/PR's for other affected example apps?

[lesv]

I have no idea how proppy manages things, so I'm going to close the issue. Just send pull requests, and for the next week, just mention lesv in the comments, so I know to look at them. I don't think you need to open an issue for each problem if your going to submit PR's.

[lesv]

P.S. Thank you for your submission.

[webmaven]

Cool, thanks for the guidance.

P.P.S. You're very welcome.