Build failing for project with matplotlib dependencies (I believe I have read every solution - HALP! 🙏)

[drvinceknight]

On a library that makes use of matplotlib (and also numpy) we only just noticed a failed build. In fact the docs stopped building in mid August 😢 but the first failing commit didn't really have anything in it that changed the docs.

You can see the issue here: Axelrod-Python/Axelrod#318 which has more information.

I have tried:

• pointing at a dummy requirements file: https://read-the-docs.readthedocs.org/en/latest/faq.html#my-project-isn-t-building-with-autodoc
• using various versions of mocking the dependencies out of the library: http://blog.rtwilson.com/how-to-make-your-sphinx-documentation-compile-with-readthedocs-when-youre-using-numpy-and-scipy/ and https://read-the-docs.readthedocs.org/en/latest/faq.html#i-get-import-errors-on-libraries-that-depend-on-c-modules
• I have read Python-3 projects depending on matplotlib & plot-directive fail indeterministically #1056 and Please provide scipy and matplotlib #217 but they do not offer any help (I found those by searching for https://github.com/rtfd/readthedocs.org/issues?utf8=%E2%9C%93&q=Builds+fail+when+using+matplotlib after reading your contributions guidelines).

I have tried a large number of changes without any luck (a co contributor and I spent pretty much all afternoon committing and reverting every single thing we could find/think off).

Ultimately I would be happy if it were possible to build the documentation without building the library at all (I think that I need to disable autodoc for that which I have also tried)...

Here is the conf.py file for the repo (on branch 318 which is being built by rtd): https://github.com/Axelrod-Python/Axelrod/blob/318/docs/conf.py

Any explanation and/or pointers would be appreciated.

[drvinceknight]

I have also tried the solutions helpfully suggested at #1624.

[capcarr]

I noticed that your setup.py file includes matplotlib in the install_requires keyword. This will probably break the installation process, but have you tried building the docs without this?

[meatballs]

The last successful build (3259753) was on August 20th at commit 67491390f6edb9e91cec2e3d04e66712924fa7bb

I've now created a 'docstest' branch at that commit and triggered build 3342236. It fails with the same error we've seen since August 20th.

[meatballs]

@capcarr thanks for the suggestion. I just tried it on build #3342348, but it made no difference.

[capcarr]

@meatballs Even when specifying an empty requirements file on RTD?

[meatballs]

Aha! I removed install_requires and then used the advanced options to use virtualenv and an empty requirements.txt created in the docs folder. It built!!

Doesn't really explain why it should suddenly have stopped, though.

[meatballs]

Is this related to commit d36ebae which is dated August 20th - the last time our docs built?

I can see it contains a change to tasks.py (line 312) that seems relevant here.

[gregmuellegger]

I'm not sure if the mentioned commit is source of the problems you have experienced. But cool that you were able to resolve the issue. The real problem here is that we cannot support installing custom versions of matplotlib (all the nasty compiling involved .. 😞) so a build will fail if matplotlib is mentioned in a requirements file or in the install_requires option.