In pypy/pypy#3980, I reported an issue I'd encountered where the repr of a datetime.datetime subclass shows a different repr depending on which implementation (C or Python) of the datetime module is used:
import sys import importlib c_impl = importlib.import_module('_datetime') sys.modules['_datetime'] = None py_impl = importlib.import_module('datetime') assert repr(py_impl.datetime(2000,1,1)) == repr(c_impl.datetime(2000,1,1)) class Fake(py_impl.datetime): pass fpy = Fake(2000,1,1) class Fake(c_impl.datetime): pass fc = Fake(2000,1,1) assert repr(fpy) == repr(fc), f'{fpy!r} != {fc!r}'
Emits as output:
Traceback (most recent call last):
File "/Users/jaraco/draft/dt.py", line 18, in <module>
assert repr(fpy) == repr(fc), f'{fpy!r} != {fc!r}'
AssertionError: __main__.Fake(2000, 1, 1, 0, 0) != Fake(2000, 1, 1, 0, 0)
This inconsistency wreaks havoc on doctests when using a library like freezegun.
Is there a way for these two implementations to share a common repr?