pip: 22.0: `assert len(weights) == expected_node_count AssertionError`

Hmmm… Maybe this needs running the pip install commands that RTD runs before those?

pip install --upgrade pip setuptools<58.3.0 
pip install --upgrade mock==1.0.1 pillow==5.4.1 alabaster>=0.7,<0.8,!=0.7.5 commonmark==0.8.1 recommonmark==0.5.0 sphinx<2 sphinx-rtd-theme<0.5 readthedocs-sphinx-ext<2.2 
pip install -r docs/requirements.txt

It might be that already-installed packages are implicated.

I am able to reproduce the error following these steps with a fresh virtual environment. Here are the steps specifically:

python3.10 -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip "setuptools<58.3.0"
python -m pip install --upgrade mock==1.0.1 pillow==5.4.1 "alabaster>=0.7,<0.8,!=0.7.5" commonmark==0.8.1 recommonmark==0.5.0 "sphinx<2" "sphinx-rtd-theme<0.5" "readthedocs-sphinx-ext<2.2"
python -m pip install -r requirements.txt

And the requirements file looks like this:

setuptools_scm
sphinx
sphinx_rtd_theme
funcparserlib==1.0.0a0
sphinxcontrib-seqdiag
numpydoc
cairocffi >= 0.9.0
cffi >= 1.1.0
xcffib >= 0.10.1

I have not been able to reproduce it using a single install or using download.

I set a breakpoint where the asert statement is and I found:

(Pdb) expected_node_count
41
(Pdb) len(weights)
42
(Pdb) weights
{'snowballstemmer': 41, 'urllib3': 41, 'alabaster': 41, 'pytz': 41, 'six': 41, 'pyparsing': 41, 'imagesize': 41, '<Python from Requires-Python>': 41, 'pygments': 41, 'pillow': 41, 'charset-normalizer': 41, 'docutils': 41, 'certifi': 41, 'setuptools': 41, 'markupsafe': 41, 'sphinxcontrib-serializinghtml': 41, 'idna': 41, 'packaging': 24, 'funcparserlib': 24, 'sphinxcontrib-websupport': 24, 'webcolors': 24, 'pycparser': 24, 'sphinxcontrib-qthelp': 24, 'sphinxcontrib-htmlhelp': 24, 'babel': 24, 'sphinxcontrib-applehelp': 24, 'tomli': 24, 'requests': 24, 'sphinxcontrib-devhelp': 24, 'sphinxcontrib-jsmath': 24, 'jinja2': 24, 'cffi': 10, 'sphinx': 10, 'setuptools-scm': 10, 'blockdiag': 10, 'cairocffi': 6, 'sphinx-rtd-theme': 6, 'numpydoc': 6, 'seqdiag': 6, 'xcffib': 6, 'sphinxcontrib-seqdiag': 1, None: 0}