Using a non-existent reference for clickable card link gives confusing error message #27
Description
Describe the problem
When creating a clickable card with :link: on the card directive (https://sphinx-design.readthedocs.io/en/furo-theme/cards.html#clickable-cards) using an internal sphinx reference, if that reference doesn't exist, you get a confusing error message:
So for example in the below snippet (from the docs) with a "missing" link reference:
.. card:: Clickable Card (internal)
:link: missing
:link-type: doc
The entire card can be clicked to navigate to the ``cards`` reference target.
This gives "AssertionError: Losing "classes" attribute: ['sd-stretched-link']" error.
You can still see that sphinx also warns about an "unknown document", but it's easy to miss that in the output.
The full traceback is included below:
Details
Running Sphinx v5.0.0+/d194e0f49
...
reading sources... [100%] index
pickling environment... done
checking consistency... done
preparing documents... done
/home/joris/scipy/pandas/doc/source/index.rst:27: WARNING: unknown document: missing
Traceback (most recent call last):
File "/home/joris/scipy/repos/sphinx/sphinx/cmd/build.py", line 280, in build_main
app.build(args.force_all, filenames)
File "/home/joris/scipy/repos/sphinx/sphinx/application.py", line 343, in build
self.builder.build_update()
File "/home/joris/scipy/repos/sphinx/sphinx/builders/__init__.py", line 293, in build_update
self.build(to_build,
File "/home/joris/scipy/repos/sphinx/sphinx/builders/__init__.py", line 357, in build
self.write(docnames, list(updated_docnames), method)
File "/home/joris/scipy/repos/sphinx/sphinx/builders/__init__.py", line 528, in write
self._write_parallel(sorted(docnames),
File "/home/joris/scipy/repos/sphinx/sphinx/builders/__init__.py", line 552, in _write_parallel
doctree = self.env.get_and_resolve_doctree(firstname, self)
File "/home/joris/scipy/repos/sphinx/sphinx/environment/__init__.py", line 532, in get_and_resolve_doctree
self.apply_post_transforms(doctree, docname)
File "/home/joris/scipy/repos/sphinx/sphinx/environment/__init__.py", line 578, in apply_post_transforms
transformer.apply_transforms()
File "/home/joris/scipy/repos/sphinx/sphinx/transforms/__init__.py", line 86, in apply_transforms
super().apply_transforms()
File "/home/joris/miniconda3/envs/pandas-dev/lib/python3.8/site-packages/docutils/transforms/__init__.py", line 171, in apply_transforms
transform.apply(**kwargs)
File "/home/joris/scipy/repos/sphinx/sphinx/transforms/post_transforms/__init__.py", line 43, in apply
self.run(**kwargs)
File "/home/joris/scipy/repos/sphinx/sphinx/transforms/post_transforms/__init__.py", line 120, in run
node.replace_self(newnodes)
File "/home/joris/miniconda3/envs/pandas-dev/lib/python3.8/site-packages/docutils/nodes.py", line 1015, in replace_self
assert not self[att], \
AssertionError: Losing "classes" attribute: ['sd-stretched-link']
Exception occurred:
File "/home/joris/miniconda3/envs/pandas-dev/lib/python3.8/site-packages/docutils/nodes.py", line 1015, in replace_self
assert not self[att], \
AssertionError: Losing "classes" attribute: ['sd-stretched-link']