I've explored the following case:
$ printf '12\n34\0' | LC_ALL=en_US.utf-8 grep -z '^[1-4]*$' | wc -c
6
It's a bug (there should be no match).
This is what grep does:
* triesto build DFA (as indfa.c)
* fails to expand character range [1-4] because of multibyte
localeen_US.utf-8 and gives up building DFA(marks [1-4] as BACKREF
that suppressesall dfa.c-related code), note the difference with
[1234] casein whichthere's no need to expand multibyte range
* falls back to Regex (gnulib extension of regex.h)
* Regex doesn't support '-z'semantics(the closest configuration to
'-z' is RE_NEWLINE_ALT, which is already included in RE_SYNTAX_GREP
set), so '\n'is treated as newline and match erroneously succeeds
I think this should be worked around in grep: before calling 're_search'
it should split the input string by 'eolbyte'.
The bug also present with PCRE engine:
$ printf '12\n34\0' | LC_ALL=en_US.utf-8 grep -z -P '^[1234]*$' | wc -c
6
$ printf '12\n34\0' | LC_ALL=en_US.utf-8 grep -z -P '^[1-4]*$' | wc -c
6
Ulya
