unnecessary-regular-expression (RUF055) treats ) as a normal character that needs no escaping, but it is actually a metacharacter. This leads to false positives and fixes that change program behavior.
$ cat ruf055.py
import re
print(re.split(r")", "a)b"))
$ python ruf055.py 2>&1 | tail -n 1
re.error: unbalanced parenthesis at position 0
$ ruff check --isolated --preview --select RUF055 ruf055.py --fix
Found 1 error (1 fixed, 0 remaining).
$ cat ruf055.py
import re
print("a)b".split(")"))
$ python ruf055.py
['a', 'b']The current behavior was inspired by this review comment, but that comment only applies to ] and }, not ).
unnecessary-regular-expression(RUF055) treats)as a normal character that needs no escaping, but it is actually a metacharacter. This leads to false positives and fixes that change program behavior.The current behavior was inspired by this review comment, but that comment only applies to
]and}, not).