bug#60618: unicode characters are not identified as such for \w and \b with -P

[Jim Meyering]

On Fri, Jan 6, 2023 at 7:49 PM Carlo Arenas <carenas@gmail.com> wrote:
> Reported to PCRE[1] with mention of GNU grep being also affected.
>
> [1] https://github.com/PCRE2Project/pcre2/issues/185

Yikes. This is a big deal.
Thank you for the patch and added test.
I made a tiny comment tweak and this test logic change that was
required to make the new test pass with the fixed version.

-grep -Po 'r\w' in > out && fail=1
+grep -Po 'r\w' in > out || fail=1

Also, make syntax-check required to change e.g.,

-compare out exp || fail=1
+compare exp out || fail=1

Every bug fix needs a NEWS entry, so I added this:

  With -P, some non-ASCII UTF8 characters were not recognized as
  word-constituent due to our omission of the PCRE_UCP flag. E.g.,
  given f(){ echo Perú|LC_ALL=en_US.UTF-8 grep -Po "$1"; } and
  this command, echo $(f 'r\w'):$(f '.\b'), before it would print ":r".
  After the fix, it prints the correct results: "rú:ú".

Finally, I expanded the ChangeLog entry and gave credit where due.

I'll push this tomorrow:

grep-pcre-fix.diff
Description: Binary data