`make epub` fails to find Furo template

[jahn-junior]

Attempting to run make epub produces the following error:

Theme error:
An error happened in rendering the page explanation/build.
Reason: TemplateNotFound("'furo/page.html' not found in ['/home/ecoldi/Projects/DOCPR/sphinx-docs-starter-pack/docs/.sphinx/venv/lib/python3.12/site-packages/canonical_sphinx/theme/templates', '/home/ecoldi/Projects/DOCPR/sphinx-docs-starter-pack/docs/.sphinx/venv/lib/python3.12/site-packages/sphinx/themes/epub', '/home/ecoldi/Projects/DOCPR/sphinx-docs-starter-pack/docs/.sphinx/venv/lib/python3.12/site-packages/sphinx/themes/basic']")
make: *** [Makefile:87: epub] Error 2

This error doesn't have anything to do with the 'Build' explanation. It'll occur on every page.

[medubelko]

I can reproduce this.

[SecondSkoll]

You need to add epub_build=True in your config.

The epub build by default has some weird interactions with template files. See canonical-sphinx for relevant code, I never really got to the bottom of why it was happening - the workaround of removing the template files for epub builds was good enough to get things to function.

This is the recommended way to get it to generate epub in RTD builds - we should probably do the same for local builds but I think I forgot to do that - and no one raised it as a problem.