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collections.UserString.rindex() fails to accept UserString as sub argument #140911
Description
Bug report
Bug description:
UserString.rindex raises a TypeError when its sub argument is a UserString object. This behavior is inconsistent with UserString.rfind and most other string methods.
from collections import UserString
us = UserString("hello world")
sub = UserString("world")
assert us.rfind(sub) == us.rfind(sub.data)
assert us.rindex(sub) == us.rindex(sub.data)Traceback (most recent call last):
File "/src/test.py", line 7, in <module>
assert us.rindex(sub) == us.rindex(sub.data)
^^^^^^^^^^^^^^
File "/py312/lib/python3.12/collections/__init__.py", line 1553, in rindex
return self.data.rindex(sub, start, end)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: must be str, not UserStringCPython versions tested on:
3.12
Operating systems tested on:
Linux
Linked PRs
- gh-140911: Ensure that UserString.rindex(), UserString.index() accept UserString as sub argument. #140945
- [3.13] gh-140911: Ensure that UserString.index() and UserString.rindex() accept UserString as argument (GH-140945) #141945
- [3.14] gh-140911: Ensure that UserString.index() and UserString.rindex() accept UserString as argument (GH-140945) #141946
Activity
picnixz commented on Nov 2, 2025
I can see that there is an isinstance check in rfind. It's legitimate to assume that we need one in rindex.
serhiy-storchaka commented on Nov 3, 2025
For reference, __contains__, count, find and replace were fixed in 98b349f. But rfind was only fixed in da2ecaf, 2.5 years later. index and rindex were missed again.
gh-140911: Ensure that UserString.index() and UserString.rindex() acc…
pythongh-140911: Ensure that UserString.index() and UserString.rindex…
pythongh-140911: Ensure that UserString.index() and UserString.rindex…
[3.13] gh-140911: Ensure that UserString.index() and UserString.rinde…
[3.14] gh-140911: Ensure that UserString.index() and UserString.rinde…
pythongh-140911: Ensure that UserString.index() and UserString.rindex…
pythongh-140911: Ensure that UserString.index() and UserString.rindex…