From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier 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 12:41:30 -0400 Message-ID: References: <83lh17ati6.fsf@gnu.org> <83h9bvarb6.fsf@gnu.org> <83mvllaa4u.fsf@gnu.org> <8360s9a7ts.fsf@gnu.org> <83shvd8qbm.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1468428147 14805 80.91.229.3 (13 Jul 2016 16:42:27 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 13 Jul 2016 16:42:27 +0000 (UTC) Cc: schwab@suse.de, 23949@debbugs.gnu.org, kaushal.modi@gmail.com To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Jul 13 18:42:16 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 1bNNEl-0007Sq-KF for geb-bug-gnu-emacs@m.gmane.org; Wed, 13 Jul 2016 18:42:15 +0200 Original-Received: from localhost ([::1]:48952 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNNEk-0006O5-Il for geb-bug-gnu-emacs@m.gmane.org; Wed, 13 Jul 2016 12:42:14 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:59479) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNNEc-0006CD-OQ for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:42:07 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bNNEY-000187-Jd for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:42:05 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:37703) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bNNEY-00017z-G9 for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:42:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1bNNEY-0006U8-3B for bug-gnu-emacs@gnu.org; Wed, 13 Jul 2016 12:42:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 13 Jul 2016 16:42:02 +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=B23949.146842809924900 (code B ref 23949); Wed, 13 Jul 2016 16:42:02 +0000 Original-Received: (at 23949) by debbugs.gnu.org; 13 Jul 2016 16:41:39 +0000 Original-Received: from localhost ([127.0.0.1]:50040 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bNNEB-0006TY-KO for submit@debbugs.gnu.org; Wed, 13 Jul 2016 12:41:39 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.181]:15573) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bNNE8-0006TJ-F5 for 23949@debbugs.gnu.org; Wed, 13 Jul 2016 12:41:37 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A0A2FgA731xV/3mcpUVcgxCEAoVVwwsEAgKBPDwRAQEBAQEBAYEKQQWDXQEBAwFWIwULCzQSFBgNJC6ICQjPIwEBAQcCAR+LOoE9AYNHB4QtBbM/gUUjgWYkDQ+BbiKCeAEBAQ X-IPAS-Result: A0A2FgA731xV/3mcpUVcgxCEAoVVwwsEAgKBPDwRAQEBAQEBAYEKQQWDXQEBAwFWIwULCzQSFBgNJC6ICQjPIwEBAQcCAR+LOoE9AYNHB4QtBbM/gUUjgWYkDQ+BbiKCeAEBAQ X-IronPort-AV: E=Sophos;i="5.13,465,1427774400"; d="scan'208";a="247779919" Original-Received: from 69-165-156-121.dsl.teksavvy.com (HELO pastel.home) ([69.165.156.121]) by ironport2-out.teksavvy.com with ESMTP; 13 Jul 2016 12:41:31 -0400 Original-Received: by pastel.home (Postfix, from userid 20848) id 587EE64CB1; Wed, 13 Jul 2016 12:41:30 -0400 (EDT) In-Reply-To: <83shvd8qbm.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 13 Jul 2016 19:18:05 +0300") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) 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:121018 Archived-At: >> >> > 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. I guess it depends what you call "run when string-match is called". For me, I look at the C backtrace and see that Fstring_match calls functions which end up calling the debugger which ends up running the rest. >> >> > (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? I think that would also fix this problem, yes. It won't fix other possible cases where the string-match could end up running Elisp code, but AFAIK there aren't any currently. > Exactly. And we are punishing the innocent (the calls that don't > signal an error) for fear of the guilty (those that do). Right. A more efficient solution would be to implement string-match-p in C alongside string-match rather than on top of it, so we can get rid of inhibit-changing-match-data (replaced by some other mechanism to propagate this info where we need it). But it's more work. Stefan