$ sphinx-build -b html . _build/html
Running Sphinx v5.3.0
WARNING: Invalid configuration value found: 'language = None'. Update your configuration to a valid language code. Falling back to 'en' (English).
WARNING: The canonical_url option is deprecated, use the html_baseurl option from Sphinx instead.
Trying to avoid this error:
Running Sphinx v1.8.5
loading translations [en]... done
making output directory...
Traceback (most recent call last):
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/cmd/build.py", line 303, in build_main
args.tags, args.verbosity, args.jobs, args.keep_going)
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/application.py", line 251, in __init__
self.emit('config-inited', self.config)
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/application.py", line 510, in emit
return self.events.emit(event, self, *args)
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/events.py", line 80, in emit
results.append(callback(*args))
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/util/compat.py", line 38, in deprecate_source_parsers
app.add_source_parser(suffix, parser)
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/application.py", line 1211, in add_source_parser
self.registry.add_source_parser(*args, **kwargs)
File "/home/docs/checkouts/readthedocs.org/user_builds/agaric-documentation/envs/latest/lib/python2.7/site-packages/sphinx/registry.py", line 310, in add_source_parser
filetype)
ExtensionError: source_parser for 'md' is already registered
Extension error:
source_parser for 'md' is already registered
