KeyError: 'classes' in sphinx\search\__init__.py

[ElpadoCan]

Describe the bug

When building the html files locally with make.bat html I get the error below. This does not happen with Sphinx<8.2. I can see that it comes from sphinx\search\__init__.py which did not exist prior v8 of Sphinx right? I hope this is enough information. Thanks!

Traceback (most recent call last):
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\cmd\build.py", line 432, in build_main
    app.build(args.force_all, args.filenames)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\application.py", line 426, in build
    self.builder.build_update()
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\__init__.py", line 375, in build_update
    self.build(
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\__init__.py", line 454, in build
    self.write(docnames, updated_docnames, method)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\__init__.py", line 735, in write
    self.write_documents(docnames)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\__init__.py", line 749, in write_documents
    self._write_serial(sorted_docnames)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\__init__.py", line 767, in _write_serial
    self.write_doc_serialized(docname, doctree)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\html\__init__.py", line 684, in write_doc_serialized
    self.index_page(docname, doctree, title)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\builders\html\__init__.py", line 1021, in index_page
    self.indexer.feed(pagename, filename, title, doctree)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 503, in feed
    word_store = self._word_collector(doctree)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 554, in _word_collector
    _feed_visit_nodes(
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 643, in _feed_visit_nodes
    _feed_visit_nodes(child, word_store=word_store, split=split, language=language)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 643, in _feed_visit_nodes
    _feed_visit_nodes(child, word_store=word_store, split=split, language=language)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 643, in _feed_visit_nodes
    _feed_visit_nodes(child, word_store=word_store, split=split, language=language)
  File "%homepath%\miniforge3\Lib\site-packages\sphinx\search\__init__.py", line 608, in _feed_visit_nodes
    elif isinstance(node, nodes.Element) and 'no-search' in node['classes']:
                                                            ~~~~^^^^^^^^^^^
  File "%homepath%\miniforge3\Lib\site-packages\docutils\nodes.py", line 602, in __getitem__
    return self.attributes[key]
            ~~~~~~~~~~~~~~~^^^^^
KeyError: 'classes'

How to Reproduce

Unfortunately, I don't know which of my documentation files is triggering this error (and I have many), however, the error does not happen with Sphinx<8.2.

Environment Information

Platform:              win32; (Windows-10-10.0.19045-SP0)
Python version:        3.12.6 | packaged by conda-forge | (main, Sep 22 2024, 14:01:26) [MSC v.1941 64 bit (AMD64)])
Python implementation: CPython
Sphinx version:        7.4.7
Docutils version:      0.21.2
Jinja2 version:        3.1.6
Pygments version:      2.19.1

Sphinx extensions

Loaded Extensions
=================

* sphinx.ext.mathjax (8.2.3)
* alabaster (0.7.16)
* sphinxcontrib.applehelp (2.0.0)
* sphinxcontrib.devhelp (2.0.0)
* sphinxcontrib.htmlhelp (2.1.0)
* sphinxcontrib.serializinghtml (2.0.0)
* sphinxcontrib.qthelp (2.0.0)
* sphinx.ext.duration (8.2.3)
* sphinx.ext.doctest (8.2.3)
* sphinx.ext.autodoc.preserve_defaults (8.2.3)
* sphinx.ext.autodoc.type_comment (8.2.3)
* sphinx.ext.autodoc.typehints (8.2.3)
* sphinx.ext.autodoc (8.2.3)
* sphinx.ext.autosummary (8.2.3)
* sphinx.ext.napoleon (8.2.3)
* sphinx_copybutton (0.5.2)
* sphinxcontrib.email (0.3.6)
* sphinx_tabs.tabs (unknown version)
* sphinx_toolbox.confval (3.9.0)
* sphinx_carousel.carousel (1.2.0)
* sphinxcontrib.video (unknown version)
* sphinxcontrib.jquery (4.1)
* sphinx_rtd_theme (unknown version)

Additional context

No response

[AA-Turner]

Are you able to provide a minimal reproducer? If not, can you please try with third-party extensions removed?

A

[ElpadoCan]

Are you able to provide a minimal reproducer? If not, can you please try with third-party extensions removed?

A

I will try. Is there any way to know more than the traceback? For example, what causes the creation of the node dictionary without classes? Because I used pdb.set_trace and many of the nodes are fine.