Subject: Re: bug#10033: 24.0.91; Uncommenting fails in Autoconf mode

From: Chong Yidong <[email-masked]>
Date: Sun, 13 Nov 2011 10:39:32 +0800

Chong Yidong <[email-masked]> writes:

> With latest trunk:
>
> emacs -Q configure.ac
> M-;
> asdf
> C-SPC M-<
> M-x uncomment-region RET
>
> The uncomment-region does nothing; the line containing "dnl asdf"
> remains commented out.

This is because the value of comment-start-skip in Autoconf mode is

   "\\(?:\\<dnl\\|#\\) +"

The \< is intended to avoid matching a "dnl" that is part of a word.  In
Emacs 23, the \< matches the beginning of the line

dnl asdf

in Autoconf mode.  But in Emacs 24, it does not match the beginning of
that line at all.  I don't see any related regexp changes in NEWS.  Does
it ring a bell for anyone?