AssertionError in visit_friendclass

[zyp]

Hi, I'm getting an AssertionError in visit_friendclass:

Running Sphinx v3.4.1
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 1 source files that are out of date
updating environment: [new config] 1 added, 0 changed, 0 removed
reading sources... [100%] index                                                                                                                                                                                                                                                
Exception occurred:
  File "/usr/local/lib/python3.8/site-packages/breathe/renderer/sphinxrenderer.py", line 1786, in visit_friendclass
    assert typ in ("friend class", "friend struct")
AssertionError
The full traceback has been saved in /var/folders/zf/y4pvt7_91q711b7ds77ysnt00000gn/T/sphinx-err-c9k68fg9.log, if you want to report the issue to the developers.
Please also report this if it was a user error, so that a better error message can be provided next time.
A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!

I checked the value of typ before the assertion and it reads simply class. Adding the following two lines to prepend friend if not already present appears to solve/work around the problem:

        typ = ''.join(n.astext() for n in self.render(node.get_type()))  # type: ignore
+       if 'friend' not in typ:
+           typ = 'friend ' + typ
        assert typ in ("friend class", "friend struct")

• Sphinx 3.4.1
• Breathe 4.25.1
• Doxygen 1.9.0

Here's a simple example to reproduce the problem: breathe_friend_error_test.tar.gz

[zyp]

If I may, what version of doxygen are you using? I'm having some friend problems with doxygen 1.9 and I'm curious if you're having a similar problem.

Originally posted by @awsteiner in #613 (comment)

Are you having the same problem as me? My problem looks unrelated to #613.

[awsteiner]

Yes I am indeed exactly having the same problem. It appeared when I upgraded doxygen, but I wasn't sure if it was a sphinx issue, a breathe issue, or a doxygen issue. I just used the preprocessor to make sure doxygen ignored the friend declarations, but I'll see if I can try your solution this week some time...

[jakobandersen]

The assert is a sanity check so while the suggested change may work it doesn't feel like the right fix. Unfortunately I can't reproduce the problem locally. Can you upload an archive of the XML folder?

[zyp]

Sure, here you go:

doxygen_xml.tar.gz

[jakobandersen]

I messed up my Doxygen compilation and it is indeed a problem starting from Doxygen 1.9. Apparently the XML output has changed. See PR #618 for the diff for your example.