Need dependency on importlib-metadata

[johnflavin]

• I read the conda-forge documentation and could not find the solution for my problem there.

Issue:

Sphinx 4.4.0 introduced a dependency on the importlib-metadata backport when installed with python < 3.10. (See sphinx-doc/sphinx#10007.) The 4.4.0 conda package does not have that dependency metadata, so installing sphinx 4.4.0 via conda-forge does not install importlib-metadata when it should.

Example:

First make an empty project.

$ conda create -n test -y "sphinx=4.4.0" "python<3.10"
$ conda activate test
$ mkdir test-dir
$ cd test-dir
$ sphinx-quickstart
< accept default options, put in "test" as name, responses don't matter >

The way I have found to trigger an error is to use a non-default theme. So I edit the conf.py to set html_theme = 'my_custom_theme'. It doesn't actually matter what the theme is, I haven't installed it, but it will never be found because of an error.

$ make html
Running Sphinx v4.4.0
loading pickled environment... done

Exception occurred:
  File "/usr/local/Caskroom/miniconda/base/envs/test/lib/python3.9/site-packages/sphinx/theming.py", line 207, in load_external_theme
    theme_entry_points = entry_points(group='sphinx.html_themes')
TypeError: entry_points() got an unexpected keyword argument 'group'
The full traceback has been saved in /var/folders/rn/37gxvfws6mvcyw4x6k18f_8m0000gp/T/sphinx-err-xhwhv03w.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
make: *** [html] Error 2

If I then install importlib-metadata, I get the (correct, expected) error about my fake theme.

$ conda install -y importlib-metadata
$ make html
Running Sphinx v4.4.0
loading pickled environment... done

Theme error:
no theme named 'my_custom_theme' found (missing theme.conf?)
make: *** [html] Error 2

[jakirkham]

Can you please submit a PR to add this to the recipe?

[johnflavin]

@jakirkham I have done this. But I'm in a bit over my head. Because I had to add a # [py<310] selector to the dependency, I had to drop noarch: python, which means I had to modify build configurations for all the platforms. Reeeally not sure I'm doing all this correctly.

[jakirkham]

Yep, that all sounds correct. Thanks for wading in here 😄

[ChrisBarker-NOAA]

Just a note:

We got bit my this recently, and have temporarily worked around it by adding import_lib to our dependencies.

Thanks for working on it!

[jakirkham]

New packages should start building soon. It takes a bit for them to build and mirror to CDN. So would recheck things in ~1hr to give time for those processes to complete.