Bug#868654: Combining Unicode Mark-Nonspacing are classified as [:punct
From Santiago R.R.@21:1/5 to All on Mon Jul 17 12:30:02 2017
Control: block 662629 by -1
There is an issue on how glibc classifies the Unicode Mark-nonspacing
category, that should be maybe [[:alpha:]] instead of [[:punct:]]. This
was identified by the bug reported to grep: https://bugs.debian.org/662629
You can test it using the U+0301 acute accent:
$ echo árbol | grep -o '[[:alpha:]]*'
This is also the opinion by grep's upstream about it:
"Surely this is a glibc bug, not a grep bug. Grep is just following the character classification of glibc. I can reproduce the problem by
compiling and running the attached program, which uses only glibc (not
grep). This program exits with status 1, whereas you want it to exit
with status 0. So I suggest filing a glibc bug report."