bug#70948: 29.3; cperl mode hangs on comments like "#___"

[Harald Jörg]

Harald Jörg <haj@posteo.de> writes:

> [...]
> The slowdown does not happen with Emacs built from the repository under
> Linux, nor with Emacs 28.2 under Windows.  I need to run more variations
> to narrow it down.

A bisection reveals that this problem does no longer occur in the
repository due to commit de6c1c4d by Mattias Engdegård (Aug 12, 2023):
"rx: Better translation of char-matching patterns" with many changes in
rx.el.

This is plausible because many rx expressions have been introduced to
cperl-mode for Emacs 29 to catch up with current Perl syntax.  I guess
that it is possible to rewrite the offending rx expression(s) so that
they do not misbehave under Emacs 29, but need to identify the culprit
now.
-- 
Cheers,
haj