Classes inheriting from other classes, defined in mocked modules, are ignored

[ederag]

As advised by @djhoese, this is a reopening of #1880.
Unfortunately, this is not #2174 (solved).
Actually, the docstrings of classes inheriting from other classes in mocked modules are ignored.
A real case is described in https://stackoverflow.com/q/50203452/3565696.
Here is a minimal working example, all files in the same directory
(also attached as sphinx-mock-bug.zip, for convenience).

Project module foo.y:

import bar

class FooClass(bar.BarClass):
    """This is myclass"""
    pass

conf.py:

import sys
import os

# The FooClass docstring shows up only if this line is commented out
autodoc_mock_imports = ['bar']

sys.path.insert(0, os.path.abspath('.'))

extensions = [
    'sphinx.ext.autodoc',
]

contents.rst:

foo
===

.. automodule:: foo
    :members:
    :noindex:

And finally, thebar.py "external" module (only used when the autodoc_mock_imports is commented out):

class BarClass():
	pass

The command used to build:
sphinx-build -b html . _build/html

To see the file where the dosctring should be visible:
firefox _build/html/foo.html

Environment info:

• Linux (openSUSE 42.2)
• Python version: 3.4.6 and 3.6.4
• Sphinx version: 1.7.4
  [and same on readthedocs for the real project]

[tk0miya]

Thank you for reporting. I'll take a look this later.

[tk0miya]

At present, it can't make subclasses of the class on mocked module.

from sphinx.ext.autodoc.importer import _MockObject

bar = _MockObject()

class FooClass(bar.BarClass):
    """docstring of FooClass"""
    pass


foo = FooClass()
print(foo)          # => <sphinx.ext.autodoc.importer._MockObject object at 0x1101fc828>
print(foo.__doc__)  # => Used by autodoc_mock_imports.

@shimizukawa Do you have any idea for this?

[tk0miya]

I just made a #4995 . I hope this resolves the issue.
@ederag Could you try this please?

[ederag]

@tk0miya Confirmed, this issue is fixed by #4995. Congratulations !
The geoptics documentation now chokes on signal lines as signal_set_all_selected = pyqtSignal(bool).
It deserves another issue, because commenting out those lines allows the build to complete.

[tk0miya]

Thank you for confirmation! I'll merge it later (after fixing CI errors).

[ederag]

The pyqtSignal issue is very close to #4931. Comment left there, with a minimal working example.

[tk0miya]

Okay, I'll check it in the thread.

[tk0miya]

Fixed by #4995
Thank you for reporting :-)

[ederag]

Now it is possible to document PyQt5 projects on readthedocs, with simple configuration tweaks.
Thanks a lot !