Circular dependency causes dependency checking tools to fail

[lseek]

sphinx specifies sphinx_rtd_theme as a dependency in tests-reqs.txt but sphinx_rtd_theme specifies sphinx>=1.1 as a dependency, thus leading to a circular dependency which causes a dependency checking tool (currently using pip-compile) to flag an error.

[birkenfeld]

Hmm, since these are not "needs to build" dependencies but "needs to run" dependencies, I don't see why the circular dependency is so bad. ("install_requires", despite the slightly misleading name, means "needs to be installed together with this one". The build-time dependency would be "setup_requires".) So please take this up with the pip-compile authors.

If that is considered inacceptable, I suggest filing this with sphinx_rtd_theme, since Sphinx definitely doesn't run without it now, while the theme doesn't "run" (or do anything) anyway if Sphinx is not present.

[jakirkham]

This appears to be suboptimal for building with conda build. When trying to build a newer version of sphinx, conda will try to fill the dependency by installing an older version of sphinx to satisfy sphinx_rtd_theme. The unfortunate consequence appears to be the final built sphinx package cannot be imported. Trying to make sphinx_rtd_theme a run requirement and not a build requirement fails as setuptools will try to download the missing requirement at build time, which is forbidden in conda build.

Could another solution please be considered? Perhaps bundling an acceptable copy of sphinx_rtd_theme as an extension (or otherwise) that can be upgraded or similar.

[birkenfeld]

Well, what do the conda people say about this?

[jakirkham]

Fair question, asked in this issue ( conda/conda-build#381 ). I tried a different manner of building here ( conda/conda-build#380 ), which has a different result. So, I can't conclusive say what the cause was, but I am a little worried about how these dependencies are setup.

[jakirkham]

Also, @birkenfeld, I have followed up on your previous point by opening an issue with sphinx_rtd_theme as seen here ( readthedocs/sphinx_rtd_theme#189 ).

[birkenfeld]

Thanks!

[karelin]

Perhaps I'm missing something, but Sphinx requires sphinx_rtd_theme in its setup.py script. It seems not 'testing requirement'. Will it be more wise not to rely on any particular themes that user may not need?

[jakirkham]

It looks like the sphinx_rtd_theme issue was closed out by this PR ( readthedocs/sphinx_rtd_theme#275 ). So, maybe we can close this out now as it is no longer a circular dependency, but just a dependency.

[tk0miya]

@jakirkham Thank you for letting us know.
Now, I close this issue.