Strange interplay with `sphinxcontrib-bibtex`

[mcocdawc]

Current Behavior

When building documentation using sphinxcontrib-bibtex together with sphinx-multiversion, citations inside Python docstrings (e.g., :cite:\...``) fail with an error such as:

docstring of quemb.molbe.fragment.fragmentate:19: WARNING: could not find bibtex key "weser_automated_2023" [bibtex.key_not_found]

However, the same citation works correctly when used in an .rst file. The error only occurs when using sphinx-multiversion, but not when using sphinx-build directly or via make html.

Expected Behavior

Citations in Python docstrings (e.g., using :cite:) should work identically whether the docs are built using sphinx-build or sphinx-multiversion.

Reproduction Steps

Steps to reproduce the behavior:

1. Clone the repo:

   git clone git@github.com:troyvvgroup/quemb.git
   cd quemb
   git checkout improve_doc
   pip install .
   cd docs
   pip install -r requirements.txt

2. Build the documentation using make (this works):

make html

3. Build the documentation manually using sphinx-build (this also works):

sphinx-build -W --keep-going -n source build/html

4. Build using sphinx-multiversion (this fails):

sphinx-multiversion -W --keep-going -n source build/html

Environment

Code appears both locally and on GitHub CI pipeline with different python versions.

My local environment:

• Ubuntu 24.04.2 LTS
• Python 3.12.3

Additional Context

• I am not sure if this is a problem of sphinxcontrib-bibtex or of sphinx-multiversion and reported the same issue also there

• Link to PR where bug appeared: Improve doc troyvvgroup/quemb#181

• The citation key exists in the literature.bib file and is used successfully in .rst files.

• I asked the question on StackOverflow.

• A dumbed down conf.py of our project looks like this

from pathlib import Path

extensions = [
    "sphinx_multiversion",
    "sphinxcontrib.bibtex",
]

CONF_DIR = Path(__file__).parent
bibtex_bibfiles = [str(CONF_DIR / "literature.bib")]