Autodoc not rendering docs for classmethod on IntEnum class

[chrisjbillington]

The classmethod in the below class is not getting picked up by autodoc when I include the class with the following:

.. autoclass:: inotify_simple.flags
    :members:

class flags(enum.IntEnum):
    """Inotify flags as defined in ``inotify.h`` but with ``IN_`` prefix omitted.
    Includes a convenience method :func:`~inotify_simple.flags.from_mask` for extracting
    flags from a mask.
    """
    @classmethod
    def from_mask(cls, mask):
        """Convenience method that returns a list of every flag in a mask."""
        return [flag for flag in cls.__members__.values() if flag & mask]

    ACCESS = 0x00000001  #: File was accessed
    MODIFY = 0x00000002  #: File was modified
    ...

To Reproduce
Steps to reproduce the behavior:

$ git clone https://github.com/chrisjbillington/inotify_simple
$ cd inotify_simple/doc
$ make html

Then open build/html/index.html and scroll down to or ctrl-f for the classinotify_simple.flags docs, and see that the from_mask() method documentation is not present.

Expected behavior
To see the method documentation for from_mask() under the class.

If I either:

• change the class to not be a subclass of enum.IntEnum or
• make the method not a classmethod

then I do see the documentation:

So it's an issue specific to the enum class and classmethods.

If I add :undoc-members: then I see the member, but without its function signature or docstring:

Your project
https://github.com/chrisjbillington/inotify_simple

Environment info

• OS: Arch Linux, fully updated
• Python version: 3.8.0
• Sphinx version: 2.2.1
• Sphinx extensions: sphinx.ext.autodoc, sphinx.ext.napoleon

Readthedocs also fails to render the docs for this classmethod, so the issue is probably not super specific to my environment.

[chrisjbillington]

Closed thinking I had found the cause and that it was my fault, reopened as it turned out that was not the case.

[chrisjbillington]

A more minimal example of the bug:

bug_demo.zip

make with make html.

[jamesharris-garmin]

I'm seeing this issue as well. I wonder if there is a clean solution for this.