GNU bug report logs - #62483
echo a | grep -E -w '((()|a)|())*' # does not terminate

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From: Jim Meyering <jim <at> meyering.net>
To: Carlo Arenas <carenas <at> gmail.com>
Cc: 62483 <at> debbugs.gnu.org, dimitry <at> andric.com, Paul Eggert <eggert <at> cs.ucla.edu>, arnold <at> skeeve.com, koen <at> chalmers.se
Subject: bug#62483: echo a | grep -E -w '((()|a)|())*' # does not terminate
Date: Sun, 2 Apr 2023 14:30:37 -0700

On Sun, Apr 2, 2023 at 1:25 PM Carlo Arenas <carenas <at> gmail.com> wrote:
> On Sun, Apr 2, 2023 at 11:30 AM Paul Eggert <eggert <at> cs.ucla.edu> wrote:
> >
> > Also, GNU grep -w passes the following more-complicated regexp to dfaparse:
>
> but AFAIK `-w` is not necessary to trigger it, as the following also
> infloops in Fedora Rawhide
>
>   $ echo a | grep -E '((()|a)|())+'

FYI, this prints its input line (and no infloop) when grep is
configured --with-included-regex, so at least for that one, it may be
due to a recent change in upstream glibc.

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