attempt to import handle napoleon from sphinx

[ktdreyer]

napoleon ships in sphinx 1.4.8 and later. Try to load the newer path first, falling back to the older sphinxcontrib path in case users do not
have sphinx installed.

Fedora has retired the python-sphinxcontrib-napoleon RPM (obsoleted by the main python-sphinx RPM), so this change allows defopt to run on Fedora when using system packages.

[evanunderscore]

I like the idea, but what can we do about the install time dependency? Presumably if you don't want to use this package you won't want to install it either. Currently sphinxcontrib-napoleon is an explicit dependency to be sure that pip install defopt is enough to give you the whole feature set. I would prefer to just depend on sphinx, but the install is massive which could be an issue for people who are only distributing a small module.

I can't think of a good way to give people the choice of which package to use while also guaranteeing things will work for a simple pip install defopt. Any ideas?

[ktdreyer]

Yeah, I was not sure what to do for the pip install case. I like that defopt does not depend on the whole of Sphinx, and the fact that pip can pull down this small napoleon module is nice, particularly when defopt itself is so lightweight.

That said, sphinxcontrib-napoleon's future is unclear to me. I assumed it would be deprecated, but it looks like @RobRuana is still maintaining it separately in addition to maintaining it in sphinx core.

Rob, can you please set our expectations about the future of the sphinxcontrib version of napoleon? In particular, how long do you plan to keep maintaining it?

(Is there some other lightweight option we could consider in this case?)

[RobRuana]

I plan on maintaining sphinxcontrib.napoleon in lockstep with sphinx.ext.napoleon for the foreseeable future. Keeping the two codebases in sync has been a trivial task so far.

One nice aspect of sphinxcontrib.napoleon is that it has no dependency on sphinx being installed, and I know at least several people are using it as a standalone library.

[ktdreyer]

Thanks Rob for the information!

I've requested that Fedora put python-sphinxcontrib-napoleon back into the distro: https://bugzilla.redhat.com/1403388 . I think we can close this PR now.

[evanunderscore]

Thanks guys. If the situation changes in the future we can reopen this discussion.