I found that object equality does not work with pygit2.Commit objects.

Digging deeper it looks like there is no implementation of __eq__ (going all the way back to object) so it falls back to __hash__, and pygit2.Commit.__hash__ is just falls back to object.__hash__.

Which causes this to happen.

python3.6.7
>>> import pygit2
>>> repo = pygit2.Repository('.')
>>> repo.head.get_object() == repo.head.get_object()
False

This behavior is confusing and work arounds are quite messy.