This was considered as bugfix in python 3.8 because bound methods should
only be equal if they are bound on the same instance, not if their
instances are equal. In Python <= 3.7 the bound method equality calls
the equivalent of instance1 == instance2 and return true based on that
and while in Python 3.8 it checks if instance1 is instance2.

You can see details about this behavior change in py3.8 
- https://bugs.python.org/issue1617161
- python-dev discussion: 
https://mail.python.org/pipermail/python-dev/2018-June/153959.html

With that and for cases of 'strict=False', oslo utils is_same_callback() method 
behaviour also changed. With 'strict=False', this method returned *True* for 
python <3.7 (because  == comparison used to call the __eq__ method return 
value) and *False* for python3.8 onwards (because == never call __eq__ method 
and check the id of self).
-https://github.com/openstack/oslo.utils/blob/7c4a94c0c3fcbd8f05541944851728f30deadd9b/oslo_utils/reflection.py#L172-L174

For 'strict' is True (which is the default) there is no behavior change because 
is_same_callback() method checks if 'self' of both bound methods are equal or 
not
- 
https://github.com/openstack/oslo.utils/blob/7c4a94c0c3fcbd8f05541944851728f30deadd9b/oslo_utils/reflection.py#L183

We should modify the test to test the behaviors this way and in
is_same_callback() method we should clearly document that 'strict' is no
more an option or valid thing for python3.8 onwards and we should even
deprecate this arg itself.

** Bug watch added: Python Roundup #1617161
   http://bugs.python.org/issue1617161

** Changed in: oslo.utils
       Status: New => Confirmed

** Changed in: oslo.utils
     Assignee: (unassigned) => Ghanshyam Mann (ghanshyammann)

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https://bugs.launchpad.net/bugs/1841072

Title:
  test_reflection.CallbackEqualityTest.test_different_instance_callbacks
  fails on Python 3.8

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