sphinx.ext.autodoc.typehints throws ValueError on pyqtSignal/Signal (PyQt5/PySide2)

[samh]

Describe the bug
Code using pyqtSignal from PyQt5 causes Sphinx to throw ValueError: no signature found for builtin <unbound signal activated>. For PySide2 (Signal), it throws ValueError: callable <PySide2.QtCore.Signal object at 0x7fa76b0c4270> is not supported by signature.

To Reproduce
Steps to reproduce the behavior:

$ git clone https://github.com/samh/sphinx-typehints-bug
$ cd sphinx-typehints-bug
$ pip install -r requirements.txt
$ make html

Expected behavior
Expected no error.

Your project
Sample project: https://github.com/samh/sphinx-typehints-bug

In my real project I am using PyQt5, but a similar error appears to happen with PySide2, and that was easier to set up for a sample.

Screenshots
If applicable, add screenshots to help explain your problem.

Output using PySide2 5.14.1:

(.venv) [samh@devdmsa sphinx-pyqt5-bug]$ make html
Running Sphinx v2.4.1
loading pickled environment... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 0 source files that are out of date
updating environment: [extensions changed ('sphinx.ext.autodoc.typehints')] 1 added, 0 changed, 0 removed
reading sources... [100%] index                                                                                                                       
Exception occurred:
  File "/opt/python36/lib/python3.6/inspect.py", line 2381, in _signature_from_callable
    raise ValueError('callable {!r} is not supported by signature'.format(obj))
ValueError: callable <PySide2.QtCore.Signal object at 0x7fa76b0c4270> is not supported by signature
The full traceback has been saved in /tmp/sphinx-err-q6sdtg7i.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!
make: *** [html] Error 2

Output using PyQt 5.4.2:

cd docs && make html
<removed>
make[1]: Entering directory `<removed>'
sphinx-build -b html -d _build/doctrees   . _build/html
Running Sphinx v2.4.1
loading pickled environment... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 0 source files that are out of date
updating environment: 0 added, 1 changed, 0 removed
reading sources... [100%] python/qt                                                                                                                                                                                                                                                                                     
Exception occurred:
  File "/opt/python36/lib/python3.6/inspect.py", line 2097, in _signature_from_builtin
    raise ValueError("no signature found for builtin {!r}".format(func))
ValueError: no signature found for builtin <unbound signal >
The full traceback has been saved in /tmp/sphinx-err-k_o1ibbv.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!
make[1]: *** [html] Error 2
make[1]: Leaving directory `<removed>'
make: *** [doc-html] Error 2

Environment info

• OS: Linux, tested on RHEL 6 and 7
• Python version: 3.6.10
• Sphinx version: 2.4.1
• Sphinx extensions: sphinx.ext.autodoc.typehints
• Extra tools: None

Additional context
Add any other context about the problem here.

• Seems to be related to https://github.com/agronholm/sphinx-autodoc-typehints/issues/18
• Error log: sphinx-err-q6sdtg7i.log

[gpotter2]

Also reproducible with any other ctypes structure.

Exception occurred:
  File "/usr/lib/python3.6/inspect.py", line 2349, in _signature_from_callable
    'no signature found for builtin type {!r}'.format(obj))
ValueError: no signature found for builtin type <class 'scapy.supersocket.tpacket_auxdata'>

[tk0miya]

Fixed. It will be released after fixing other reported bug.
Thank you for reporting!