3.4.0 inspect.getslots fail with TypeError

[ravwojdyla]

After upgrade from 3.3.1 to 3.4.0 Dask's doc CI is failing with:

Exception occurred:
  File "/usr/local/lib/python3.8/site-packages/sphinx/util/inspect.py", line 193, in getslots
    raise TypeError
TypeError

Full stacktrace

  File "/usr/local/bin/sphinx-build", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.8/site-packages/sphinx/cmd/build.py", line 294, in main
    return build_main(argv)
  File "/usr/local/lib/python3.8/site-packages/sphinx/cmd/build.py", line 280, in build_main
    app.build(args.force_all, filenames)
  File "/usr/local/lib/python3.8/site-packages/sphinx/application.py", line 352, in build                                                                                                                                                                                                                                                                                                                                                                                                        self.builder.build_update()
  File "/usr/local/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 296, in build_update                                                                                                                                                                                                                                                                                                                                                                                           self.build(to_build,
  File "/usr/local/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 310, in build                                                                                                                                                                                                                                                                                                                                                                                                  updated_docnames = set(self.read())
  File "/usr/local/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 417, in read
    self._read_serial(docnames)                                                                                                                                                                                                                                                                                                                                                                                                                                                                File "/usr/local/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 438, in _read_serial
    self.read_doc(docname)
  File "/usr/local/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 478, in read_doc                                                                                                                                                                                                                                                                                                                                                                                               doctree = read_doc(self.app, self.env, self.env.doc2path(docname))
  File "/usr/local/lib/python3.8/site-packages/sphinx/io.py", line 221, in read_doc
    pub.publish()                                                                                                                                                                                                                                                                                                                                                                                                                                                                              File "/usr/local/lib/python3.8/site-packages/docutils/core.py", line 217, in publish
    self.document = self.reader.read(self.source, self.parser,
  File "/usr/local/lib/python3.8/site-packages/sphinx/io.py", line 126, in read                                                                                                                                                                                                                                                                                                                                                                                                                  self.parse()
  File "/usr/local/lib/python3.8/site-packages/docutils/readers/__init__.py", line 77, in parse
    self.parser.parse(self.input, document)                                                                                                                                                                                                                                                                                                                                                                                                                                                    File "/usr/local/lib/python3.8/site-packages/sphinx/parsers.py", line 104, in parse
    self.statemachine.run(inputlines, document, inliner=self.inliner)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 170, in run                                                                                                                                                                                                                                                                                                                                                                                                 results = StateMachineWS.run(self, input_lines, input_offset,                                                                                                                                                                                                                                                                                                                                                                                                                              File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 241, in run
    context, next_state, result = self.check_line(
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 459, in check_line                                                                                                                                                                                                                                                                                                                                                                                                return method(match, context, next_state)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2769, in underline                                                                                                                                                                                                                                                                                                                                                                                          self.section(title, source, style, lineno - 1, messages)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 327, in section                                                                                                                                                                                                                                                                                                                                                                                             self.new_subsection(title, lineno, messages)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 393, in new_subsection                                                                                                                                                                                                                                                                                                                                                                                      newabsoffset = self.nested_parse(
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 281, in nested_parse
    state_machine.run(block, input_offset, memo=self.memo,
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 196, in run
    results = StateMachineWS.run(self, input_lines, input_offset)
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 241, in run
    context, next_state, result = self.check_line(
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 459, in check_line
    return method(match, context, next_state)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2769, in underline
    self.section(title, source, style, lineno - 1, messages)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 327, in section
    self.new_subsection(title, lineno, messages)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 393, in new_subsection
    newabsoffset = self.nested_parse(
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 281, in nested_parse
    state_machine.run(block, input_offset, memo=self.memo,
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 196, in run
    results = StateMachineWS.run(self, input_lines, input_offset)
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 241, in run
    context, next_state, result = self.check_line(
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 459, in check_line
    return method(match, context, next_state)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2344, in explicit_markup
    self.explicit_list(blank_finish)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2369, in explicit_list
    newline_offset, blank_finish = self.nested_list_parse(
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 318, in nested_list_parse
    state_machine.run(block, input_offset, memo=self.memo,
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 196, in run
    results = StateMachineWS.run(self, input_lines, input_offset)
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 241, in run
    context, next_state, result = self.check_line(
  File "/usr/local/lib/python3.8/site-packages/docutils/statemachine.py", line 459, in check_line
    return method(match, context, next_state)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2647, in explicit_markup
    nodelist, blank_finish = self.explicit_construct(match)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2354, in explicit_construct
    return method(self, expmatch)
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2096, in directive
    return self.run_directive(
  File "/usr/local/lib/python3.8/site-packages/docutils/parsers/rst/states.py", line 2146, in run_directive
    result = directive_instance.run()
  File "/usr/local/lib/python3.8/site-packages/sphinx/ext/autosummary/__init__.py", line 247, in run
    items = self.get_items(names)
  File "/usr/local/lib/python3.8/site-packages/sphinx/ext/autosummary/__init__.py", line 349, in get_items
    if not documenter.import_object():
  File "/usr/local/lib/python3.8/site-packages/sphinx/ext/autodoc/__init__.py", line 2314, in import_object
    ret = super().import_object(raiseerror=True)
  File "/usr/local/lib/python3.8/site-packages/sphinx/ext/autodoc/__init__.py", line 2122, in import_object
    if self.isslotsattribute():
  File "/usr/local/lib/python3.8/site-packages/sphinx/ext/autodoc/__init__.py", line 2112, in isslotsattribute
    __slots__ = inspect.getslots(self.parent)
  File "/usr/local/lib/python3.8/site-packages/sphinx/util/inspect.py", line 194, in getslots
    traceback.print_stack()

The error seem to be that

sphinx/sphinx/ext/autodoc/__init__.py

Line 2112 in a7e10c1

__slots__ = inspect.getslots(self.parent)

gets module as an argument which raises TypeError, which is not captured and raises up. Would it be enough to just add TypeError to except, or is there a better way to handle this. In the meantime created a PR with the TypeError ignore.

See issue: dask/dask#7001, example of failure: doc CI.

To Reproduce

1. clone dask master
2. follow instructions from https://github.com/dask/dask/blob/master/docs/README.rst

Environment info

• OS: [e.g. Unix/Linux/Mac]
• Python version: 3.8
• Sphinx version: 3.4.0

Additional context
dask/dask#7001