Por alguna razón, hemos encontrado UPC/ravada#890 en la CI de readthedocs, y actualmente los builds tienen el siguiente error:

% python -m sphinx -T -j auto -E -b html -d _build/doctrees -D language=es . _build/html
Running Sphinx v2.2.0

Traceback (most recent call last):
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/config.py", line 361, in eval_config_file
    execfile_(filename, namespace)
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/util/pycompat.py", line 81, in execfile_
    exec(code, _globals)
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 22, in <module>
    from conf import *
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 72, in <module>
    if extensions:
NameError: name 'extensions' is not defined

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/cmd/build.py", line 272, in build_main
    app = Sphinx(args.sourcedir, args.confdir, args.outputdir,
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/application.py", line 210, in __init__
    self.config = Config.read(self.confdir, confoverrides or {}, self.tags)
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/config.py", line 196, in read
    namespace = eval_config_file(filename, tags)
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/config.py", line 371, in eval_config_file
    raise ConfigError(msg % traceback.format_exc())
sphinx.errors.ConfigError: There is a programmable error in your configuration file:

Traceback (most recent call last):
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/config.py", line 361, in eval_config_file
    execfile_(filename, namespace)
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/util/pycompat.py", line 81, in execfile_
    exec(code, _globals)
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 22, in <module>
    from conf import *
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 72, in <module>
    if extensions:
NameError: name 'extensions' is not defined


Configuration error:
There is a programmable error in your configuration file:

Traceback (most recent call last):
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/config.py", line 361, in eval_config_file
    execfile_(filename, namespace)
  File "/home/cmaureir/repos/python-docs-es-admin/venv/lib/python3.9/site-packages/sphinx/util/pycompat.py", line 81, in execfile_
    exec(code, _globals)
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 22, in <module>
    from conf import *
  File "/home/cmaureir/repos/python-docs-es-admin/conf.py", line 72, in <module>
    if extensions:
NameError: name 'extensions' is not defined

Localmente extensions está definido, pero por alguna razón no en el CI de readthedocs.