This bug was introduced at 2.0 (commit 669f9c3a) (sorry)

autodoc crashes when the target object raises an exception on
`hasattr()`.  The `hasattr()` function internally calls the
`obj.__getattr__()` or `obj.__getattribute__()` of the target object.
Hence the reaction can be changed on the target object.

This starts to use `safe_getattr()` to check the object is mocked or not
and to prevent an unexpected error.

.. note::

   $ find sphinx tests LICENSE doc/conf.py -type f -exec sed -i '' -e 's/2007\-20../2007-2021/' {} \;
   $ git co sphinx/locale/**/*.js sphinx/templates/epub3/mimetype