readthedocs: fix docs build

Author: dlech

.readthedocs.yaml

@@ -12,9 +12,10 @@ build:
   jobs:
     post_create_environment:
       - pip install poetry
-      - poetry config virtualenvs.create false
     post_install:
-      - poetry install --only=docs
+      # VIRTUAL_ENV needs to be set manually for now.
+      # See https://github.com/readthedocs/readthedocs.org/pull/11152/
+      - VIRTUAL_ENV=$READTHEDOCS_VIRTUALENV_PATH poetry install --only=docs
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:

docs/conf.py

@@ -16,8 +16,6 @@
 
 import toml
 
-ON_RTD = os.environ.get("READTHEDOCS", None) == "True"
-
 # so we have single source of project info
 _pyproject = toml.load("../pyproject.toml")
 
@@ -83,10 +81,7 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-if ON_RTD:
-    html_theme = "default"
-else:
-    html_theme = "sphinx_rtd_theme"
+html_theme = "sphinx_rtd_theme"
 
 
 # Add any paths that contain custom static files (such as style sheets) here,