Move docopt and yarg imports to local scope

[befeleme]

I wonder, would you consider moving the imported libraries from global to local scope?

My motivation comes from pipenv which bundles pipreqs alongside with its dependencies (yarg and docopt), but it really uses only two functions (get_all_imports, get_pkg_names) which don't require them.
When moved, pipenv could stop bundling yarg and docopt.

[coveralls]

Coverage decreased (-0.1%) to 71.255% when pulling 8c0f54a on befeleme:imports into 90102ac on bndr:master.

[coveralls]

Coverage decreased (-0.1%) to 71.255% when pulling 8c0f54a on befeleme:imports into 90102ac on bndr:master.

[coveralls]

Coverage decreased (-0.1%) to 71.255% when pulling 8c0f54a on befeleme:imports into 90102ac on bndr:master.

[alan-barzilay]

@befeleme I'm not sure I understood your motivation, pipreqs is not a dependency of pipenv and I couldn't find anything that mentions pipreqs being bundled with pipenv. Could you provide a source regarding this?

[befeleme]

Sure! See vendored dependencies of pipenv. It looks pipreqs is bundled alongside with its installable dependencies and used in this function. The two dependencies mentioned in the PR are only pulled to make pipreqs import correctly.

Regarding why - pipenv comes with so many bundled libraries, it's huge. I am currently testing pipenv's dependencies in Fedora, as we prefer to debundle and pull them directly. To be fair, removing two of them will not significantly reduce the size of pipenv, but it's feasible and reduces a drop of its complexity.

[alan-barzilay]

@befeleme I see, thank you for the detailed response!
pipreqs was unmaintained for a while and I'm the new (and afaik sole) maintainer. I have a few plans for this project but they aren't set in stone yet, at the moment I'm focusing on issue #252 and it may lead to a refactoring that could break up the pipreqs.py file into smaller ones. This would probably resolve your issue with yarg and docopt.
I don't know yet how or if this is going to work but I would rather wait for the next release to be more mature before considering merging this PR. Even if I merged your PR right now it wouldn't be available until the next release, so I thing there is no harm in waiting and thinking a bit more.

[befeleme]

@alan-barzilay, thanks for taking time to look at this issue :) Your point is completely understandable to me. Good luck with the refactoring efforts!