Subject: bug#18762: [PATCH] dfa: don't consider RE_DOT_NEWLINE and RE_DOT_NOT_NULL in matching with a bracket expression

From: Jim Meyering <[email-masked]>
Date: Sat, 18 Oct 2014 10:06:33 -0700

On Sat, Oct 18, 2014 at 5:39 AM, Norihiro Tanaka <[email-masked]> wrote:
> RE_DOT_NEW_LINE and NOT_NULL work for '.' only in regex.  OTOH, they
> work for MBCSET in addition to '.' in DFA.  This patch adapts the behavior
> of DFA to of regex.
>
> BTW, at the moment, grep and gawk never use match_mb_charset function to
> be fixed by it.

Thank you for the patch. It is clearly correct.
However, it presents a puzzle: does your patch induce any semantic
change in grep?
I.e., is this a bug fix, or simply the removal of code that would have
no effect.
So far, I have been unable to construct a case for which it induces a
semantic change.

On the other hand, this does eliminate a few comparisons,
so there may be a small performance improvement.