From: Tomi Ollila <tomi.ollila@iki.fi>
To: Austin Clements <amdragon@MIT.EDU>, notmuch@notmuchmail.org
Subject: Re: [PATCH] emacs: Fix trimming regexp in notmuch-check-exit-status
In-Reply-To: <1368821643-24179-1-git-send-email-amdragon@mit.edu>
References: <1368821643-24179-1-git-send-email-amdragon@mit.edu>
User-Agent: Notmuch/0.15.2+99~g7e455bc (http://notmuchmail.org) Emacs/24.3.1
	(x86_64-unknown-linux-gnu)
Date: Sat, 18 May 2013 16:45:30 +0300
Message-ID: <m2ip2gjtad.fsf@guru.guru-group.fi>
MIME-Version: 1.0
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Precedence: list

On Fri, May 17 2013, Austin Clements <amdragon@MIT.EDU> wrote:

> For such a simple regexp, this was broken in a very complicated way.
>
> The intent was to strip the newline (and potentially other whitespace)
> off the end of the error string so there wasn't an extra newline in
> the error signal.  However, the regexp was deeply dependent on the
> active syntax table and the subtleties of $.  We didn't notice this
> because all notmuch major modes put ?\n in the whitespace class, which
> makes this behaved as intended: the "\\s " matches all newlines, but
> by matching the newline character, causes the $ *not* to match
> *except* where it matched the empty string at the very end of the
> string, which was not followed by a newline.
>
> However, if the syntax table declares ?\n to be non-whitespace
> (lisp-mode declares it as endcomment, and is likely to be the mode
> you're in when testing functions), then this regexp behaves completely
> differently, matching trailing spaces at the end of every line within
> the string.
>
> The solution is to say what we mean for whitespace *and* to switch
> from $ to \', which matches only the end of the string, rather than
> the end of each line.  Both are necessary or this will strip away
> interior newlines, which is not what we want.

LGTM.

Tomi


> ---
>  emacs/notmuch-lib.el |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
> index 790136e..59b1ce3 100644
> --- a/emacs/notmuch-lib.el
> +++ b/emacs/notmuch-lib.el
> @@ -438,7 +438,7 @@ You may need to restart Emacs or upgrade your notmuch package."))
>  	(if err
>  	    ;; We have an error message straight from the CLI.
>  	    (notmuch-logged-error
> -	     (replace-regexp-in-string "\\s $" "" err) extra)
> +	     (replace-regexp-in-string "[ \n\r\t\f]*\\'" "" err) extra)
>  	  ;; We only have combined output from the CLI; don't inundate
>  	  ;; the user with it.  Mimic `process-lines'.
>  	  (notmuch-logged-error (format "%s exited with status %s"
> -- 
> 1.7.10.4
>
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