🧪 Turn warnings into errors in docs build envs

Author: webknjaz

.readthedocs.yaml

@@ -13,14 +13,19 @@ build:
     python: >-
       3.10
   commands:
-  - python -Im venv "${READTHEDOCS_VIRTUALENV_PATH}"
   - >-
+    PYTHONWARNINGS=error
+    python -Im venv "${READTHEDOCS_VIRTUALENV_PATH}"
+  - >-
+    PYTHONWARNINGS=error
     "${READTHEDOCS_VIRTUALENV_PATH}"/bin/python -Im
     pip install tox
   - >-
+    PYTHONWARNINGS=error
     "${READTHEDOCS_VIRTUALENV_PATH}"/bin/python -Im
     tox -e build-docs --notest -vvvvv
   - >-
+    PYTHONWARNINGS=error
     SPHINX_BUILDER=dirhtml
     SPHINX_BUILD_OUTPUT_DIRECTORY="${READTHEDOCS_OUTPUT}"/html
     "${READTHEDOCS_VIRTUALENV_PATH}"/bin/python -Im

tox.ini

@@ -355,6 +355,8 @@ passenv =
   SPHINX_BUILDER
   SPHINX_BUILD_OUTPUT_DIRECTORY
   SSH_AUTH_SOCK
+setenv =
+  PYTHONWARNINGS = error
 skip_install = true