Fix broken docs environment in tox.ini (#2720)

* Lock libsass version

Our requirements files already lock libsass to 0.15.1, but since the
pyproject.toml file doesn't, it leads to problems when building e.g. tox
environments on some Linux distros (particularly, on NixOS, it ends up
download a Python egg with a binary that declares dynamic dependencies
incompatible with NixOS)

* Make tox docs env more like the default testenv

Various strange problems (that differ between developers) kept cropping
up when trying to build the docs environment using the "old" method with
pip-tools.

This resets the doc environment to look more like we now handle the
default testenv in tox.ini, and should therefore also fix the doc builds.

Authored by: Morten Brekkevold <[email protected]>

pyproject.toml

@@ -1,5 +1,5 @@
 [build-system]
-requires = ["setuptools>=61.0", "wheel", "setuptools_scm[toml]>=6.2", "libsass"]
+requires = ["setuptools>=61.0", "wheel", "setuptools_scm[toml]>=6.2", "libsass==0.15.1"]
 build-backend = "setuptools.build_meta"
 
 [project]

tox.ini

@@ -113,17 +113,17 @@ commands =
 
 [testenv:docs]
 description = Just build the Sphinx documentation
-deps = pip-tools
+deps =
+    -r doc/requirements.txt
+
+usedevelop = true
 setenv =
     PYTHONPATH = {toxinidir}/python:{toxinidir}/tests
     DJANGO_SETTINGS_MODULE = nav.django.settings
     LC_ALL=C.UTF-8
     LANG=C.UTF-8
     VIRTUALENV_PIP=23.1.0
 allowlist_externals = sh
-commands_pre =
-         pip-compile --resolver=backtracking --output-file {envdir}/requirements.txt doc/requirements.txt
-         pip-sync {envdir}/requirements.txt
 commands =
          sphinx-build doc/ doc/_build/
          sh -c "cd doc; python -c 'import conf; print(conf.version)' > {toxinidir}/reports/doc_version"