GNU bug report logs - #60697
GNU grep mishandles \b near encoding errors

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: bug-grep <at> gnu.org
Subject: GNU grep mishandles \b near encoding errors
Date: Mon, 9 Jan 2023 15:00:15 -0800

Here's a shell session illustrating the problem on Fedora 37, which has 
GNU grep 3.7. The same bug is still in bleeding-edge GNU grep.

  $ export LC_ALL=en_US.utf8
  $ printf '\300\n' | grep '\b'
  grep: (standard input): binary file matches
  $ printf '\300\n' | grep -P '\b'
  $

Plain grep finds a word boundary in the input even though the input 
contains no words (just an encoding error). 'grep -P' does the right thing.

The underlying issue is in the glibc regex code so the fix should be in 
glibc / Gnulib, but I thought I'd report it here before I forgot it.

Message #8 received at 60697 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 60697 <at> debbugs.gnu.org
Subject: Re: bug#60697: GNU grep mishandles \b near encoding errors
Date: Wed, 11 Jan 2023 22:03:52 -0800

On Mon, Jan 9, 2023 at 10:16 PM Paul Eggert <eggert <at> cs.ucla.edu> wrote:
> Here's a shell session illustrating the problem on Fedora 37, which has
> GNU grep 3.7. The same bug is still in bleeding-edge GNU grep.
>
>    $ export LC_ALL=en_US.utf8
>    $ printf '\300\n' | grep '\b'
>    grep: (standard input): binary file matches
>    $ printf '\300\n' | grep -P '\b'
>    $
>
> Plain grep finds a word boundary in the input even though the input
> contains no words (just an encoding error). 'grep -P' does the right thing.
>
> The underlying issue is in the glibc regex code so the fix should be in
> glibc / Gnulib, but I thought I'd report it here before I forgot it.

Thanks! While this would definitely be nice to fix before the release
(in the next week or so), it's enough of a corner case that I wouldn't
feel bad releasing without a fix.

For the record, this problem first arose in grep-2.19.

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