In Python 3.9.5+ urllib.parse() automatically removes ASCII newlines
and tabs from URLs [1, 2]. Unfortunately it created an issue in
the URLValidator. URLValidator uses urllib.urlsplit() and
urllib.urlunsplit() for creating a URL variant with Punycode which no
longer contains newlines and tabs in Python 3.9.5+. As a consequence,
the regular expression matched the URL (without unsafe characters) and
the source value (with unsafe characters) was considered valid.
[1] https://bugs.python.org/issue43882 and
[2] 76cd81d603
Backport of e1e81aa1c4 from main.
Mariusz Felisiak
Simon Charette
Carlton Gibson