If '\Z' matches as part of a pattern in re.sub() or re.split(), it should consume the end of string, and then '\Z' alone should not match the end of string again.

Current behavior:

Python 3.9.2 (tags/v3.9.2:1a79785, Feb 19 2021, 13:44:55) [MSC v.1928 64 bit (AMD64)] on win32
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>>> import re
>>> print(re.split(r'/?\Z', 'a/b/c/d/'))
['a/b/c/d', '', '']
>>> print(re.sub(r'/?\Z', '-', 'a/b/c/d/'))
a/b/c/d--


Wanted behavior:

>>> print(re.split(r'/?\Z', 'a/b/c/d/'))
['a/b/c/d', '']
>>> print(re.sub(r'/?\Z', '-', 'a/b/c/d/'))
a/b/c/d-