From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#23949: 25.0.95; Regression in handling error caused by (string-match-p "." nil) Date: Wed, 13 Jul 2016 19:18:05 +0300 Message-ID: <83shvd8qbm.fsf@gnu.org> References: <83lh17ati6.fsf@gnu.org> <83h9bvarb6.fsf@gnu.org> <83mvllaa4u.fsf@gnu.org> <8360s9a7ts.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1468426779 25379 80.91.229.3 (13 Jul 2016 16:19:39 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 13 Jul 2016 16:19:39 +0000 (UTC) Cc: schwab@suse.de, 23949@debbugs.gnu.org, kaushal.modi@gmail.com To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Jul 13 18:19:24 2016 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bNMsa-0000DD-1b for geb-bug-gnu-emacs@m.gmane.org; Wed, 13 Jul 2016 18:19:20 +0200 Original-Received: from localhost ([::1]:48845 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNMsT-0004i5-JY for geb-bug-gnu-emacs@m.gmane.org; Wed, 13 Jul 2016 12:19:13 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:54639) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNMsN-0004hk-6L for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:19:08 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bNMsI-0004uQ-Q7 for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:19:06 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:37699) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNMsI-0004uL-Mt for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:19:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1bNMsI-0005w9-JA for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:19:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 13 Jul 2016 16:19:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 23949 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 23949-submit@debbugs.gnu.org id=B23949.146842671722785 (code B ref 23949); Wed, 13 Jul 2016 16:19:02 +0000 Original-Received: (at 23949) by debbugs.gnu.org; 13 Jul 2016 16:18:37 +0000 Original-Received: from localhost ([127.0.0.1]:50036 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bNMrt-0005vR-JL for submit@debbugs.gnu.org; Wed, 13 Jul 2016 12:18:37 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:35264) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bNMrr-0005vD-Hl for 23949@debbugs.gnu.org; Wed, 13 Jul 2016 12:18:36 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bNMri-0004fc-4D for 23949@debbugs.gnu.org; Wed, 13 Jul 2016 12:18:30 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:57332) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNMri-0004fQ-0c; Wed, 13 Jul 2016 12:18:26 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:4125 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bNMrg-0002CY-0S; Wed, 13 Jul 2016 12:18:24 -0400 In-reply-to: (message from Stefan Monnier on Wed, 13 Jul 2016 12:00:40 -0400) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:121017 Archived-At: > From: Stefan Monnier > Cc: kaushal.modi@gmail.com, schwab@suse.de, 23949@debbugs.gnu.org > Date: Wed, 13 Jul 2016 12:00:40 -0400 > > >> > I also think that the "breaks a lot of Elisp code" part is at least a > >> > tad exaggerated. > >> Binding inhibit-changing-match-data to t will pretty much break any > >> function that uses match-beginning or match-end. > > But those functions aren't supposed to run when string-match is > > called. > > Yet they are in bug#23949. No, they aren't. They run from the debugger. > >> > (defsubst string-match-p (regexp string &optional start) > >> > "\ > >> > Same as `string-match' except this function does not change the match data." > >> > (condition-case err > >> > (let ((inhibit-changing-match-data t)) > >> > (string-match regexp string start)) > >> > (error (signal (car err) (cdr err))))) > >> That will still cause the same problems when debug-on-signal is non-nil. > > So you don't consider this an improvement that should be installed? > > No. What about the suggestion made by Andreas? > A simpler and more robust solution would be > (save-match-data (string-match regexp string start)) > > Of course, with either solution, it means that string-match-p is even > worse in terms of efficiency, whereas the unsuspecting coder would > rightfully expect string-match-p to be (slightly) *more* efficient than > string-match. Exactly. And we are punishing the innocent (the calls that don't signal an error) for fear of the guilty (those that do).