From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" Newsgroups: gmane.emacs.bugs Subject: bug#64128: regexp parser zero-width assertion bugs Date: Mon, 19 Jun 2023 08:54:22 -0400 Message-ID: References: <4A303177-384E-4FEF-98F2-FAB89A12ACC9@gmail.com> <83pm5tpdy2.fsf@gnu.org> Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="25110"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Eli Zaretskii , Paul Eggert , 64128@debbugs.gnu.org To: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jun 19 15:30:03 2023 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qBExH-0006Om-6j for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 19 Jun 2023 15:30:03 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qBEPT-00074C-1F; Mon, 19 Jun 2023 08:55:07 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qBEPO-000731-U6 for bug-gnu-emacs@gnu.org; Mon, 19 Jun 2023 08:55:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qBEPO-0006Vx-KN for bug-gnu-emacs@gnu.org; Mon, 19 Jun 2023 08:55:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1qBEPO-0006SH-1G for bug-gnu-emacs@gnu.org; Mon, 19 Jun 2023 08:55:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 19 Jun 2023 12:55:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 64128 X-GNU-PR-Package: emacs Original-Received: via spool by 64128-submit@debbugs.gnu.org id=B64128.168717927224766 (code B ref 64128); Mon, 19 Jun 2023 12:55:01 +0000 Original-Received: (at 64128) by debbugs.gnu.org; 19 Jun 2023 12:54:32 +0000 Original-Received: from localhost ([127.0.0.1]:55784 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qBEOu-0006RN-Cd for submit@debbugs.gnu.org; Mon, 19 Jun 2023 08:54:32 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:40057) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1qBEOs-0006R9-M1 for 64128@debbugs.gnu.org; Mon, 19 Jun 2023 08:54:31 -0400 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 18D8A44219A; Mon, 19 Jun 2023 08:54:25 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 9961D44214A; Mon, 19 Jun 2023 08:54:23 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1687179263; bh=WhC3uPu+qb0kUmQqnlG+M8OMm4/nmpPKH7UKqaYXYV8=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Yd/TBFlMHH09YSkwgzRhdT8V25heSsqCAUEX/2iyQkkieP1qvjmxcTLyn1CXNboTq 3W++PuttOflCX1ldwGj9Ihq/kYdT/m23PYgGG1tawwM4ph/CdIQnVczL/lPh6CkVk2 JulJzaUyo1lMDK4yp5DFSK40n5eZFOXfZF7WvRvxV0f4zzZTYzNglQho/GsuKUN3wc GyxbRuETk+dIws/WE0Nh5GK04H/DtmcR+yOnxJsKtt6gwVgWlKkDUqxIuxKNSaTCvR rKiNVkG+ttXtXI8FthKGR9DT1YmzCWltEMMpLuwO3efBb8/ok+oqjMnwAmYbp0lcPP mMy9wDDeYkq+Q== Original-Received: from pastel (unknown [45.72.207.87]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 6B15712086B; Mon, 19 Jun 2023 08:54:23 -0400 (EDT) In-Reply-To: ("Mattias =?UTF-8?Q?Engdeg=C3=A5rd?="'s message of "Mon, 19 Jun 2023 10:44:04 +0200") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:263681 Archived-At: I wish there was a way to emit warnings about oddball constructs (starting with the "* is literal when encountered at the beginning of a regexp"). Stefan Mattias Engdeg=E5rd [2023-06-19 10:44:04] wrote: > 19 juni 2023 kl. 05.04 skrev Stefan Monnier : > >> `^` is only special if it's at the beginning of a group, so `^*` will >> always treat this * as a literal, right? >> "Similarly" `$` is only special if it's at the end of a group, so `$*` w= ill >> always be a repetition of the $ character no? > > Yes, ^ and $ have additional rules for when they are plain literals and n= ot > subject to these bugs at all. > > The literal-splitting powers of ^ have now (075e77ac44) been removed. > >> So the remaining problematic elements are \` \' \b and \B > > \`* has been observed, so we probably need to keep that working as well. > >> I suspect if we don't want to signal errors, the next best thing is to >> treat them like group B. > > Yes, maybe; they are less likely to be followed by an operator-literal, b= ut > it would also be good to have all zero-width assertions work the same way. > On the other hand, it can't be worse than we have now, as long as we get = rid > of the "quack,\\b*" semantics.