Extension Error - Could not import extension nbsphinx_link

[sahilk45]

Describe the bug

I encountered an error while trying to build my Sphinx documentation using sphinx-build -b html . _build. The build process fails with an ExtensionError, stating that the nbsphinx_link module is missing.

Running Sphinx v8.2.3
loading translations [en]... done

Extension error!

Versions

• Platform: win32; (Windows-11-10.0.22631-SP0)
• Python version: 3.13.2 (CPython)
• Sphinx version: 8.2.3
• Docutils version: 0.21.2
• Jinja2 version: 3.1.6
• Pygments version: 2.19.1

Traceback

  File "C:\Users\HP\AppData\Local\Programs\Python\Python313\Lib\site-packages\sphinx\registry.py", line 544, in load_extension     
    raise ExtensionError(
        __('Could not import extension %s') % extname, err
    ) from err
sphinx.errors.ExtensionError: Could not import extension nbsphinx_link (exception: No module named 'nbsphinx_link')

The full traceback has been saved in:
C:\Users\HP\AppData\Local\Temp\sphinx-err-g4t7ub7z.log

How to Reproduce

1. Run the command :

sphinx-build -b html . _build
2.The build process fails with the above error.

Environment Information

Operating System: Windows 11 (Version 22631)
Python Version: 3.13.2 (CPython)
Sphinx Version: 8.2.3
Docutils Version: 0.21.2
Jinja2 Version: 3.1.6
Pygments Version: 2.19.1

Sphinx extensions

Additional context

Possible Fix / Workaround
Manually installing the missing extension (nbsphinx_link) using:

pip install nbsphinx_link

resolved the issue.

Could this missing dependency be added to the documentation or a clearer error message be provided? Let me know if any additional details are needed.

Thanks!

[AA-Turner]

nbsphinx-link is a third party dependency, please create an issue with that project.

A

[mgeier]

As far as I understood the issue description, the problem is that it's not clear from the error message that the nbsphinx-link package has to be installed.

This happens without nbsphinx-link being installed, therefore it cannot be an issue with that project, right?
(except for documentation, see below)

It sounds like a Sphinx issue to me, but I don't know if there is a feasible course of action for this ...

I think the problem is that the module name and the PyPI package name are sometimes (often?) different, and Sphinx knows only the former and can therefore give no hints on how to install the latter.

(Part of) the problem might also be a documentation problem, since the README in https://github.com/vidartf/nbsphinx-link/ states "Install the package", but it doesn't state how to do that (nor how the PyPI package is actually named, thought the first guess would likely be right).