From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#36431: Crash in marker.c:337 Date: Wed, 03 Jul 2019 12:19:22 -0400 Message-ID: References: <20190629.131734.877718102639559715.wl@gnu.org> <831rzch9nd.fsf@gnu.org> <83zhm0fuqg.fsf@gnu.org> <83ftnrf87e.fsf@gnu.org> <83v9wkcp3z.fsf@gnu.org> <83sgrocmws.fsf@gnu.org> <83pnmschvy.fsf@gnu.org> <83lfxfd8om.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="147063"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) Cc: 36431@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Jul 03 18:30:46 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hii9Y-000bpk-EW for geb-bug-gnu-emacs@m.gmane.org; Wed, 03 Jul 2019 18:30:40 +0200 Original-Received: from localhost ([::1]:37340 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hii22-0006FN-56 for geb-bug-gnu-emacs@m.gmane.org; Wed, 03 Jul 2019 12:22:55 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:60445) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hihzH-0005ye-ET for bug-gnu-emacs@gnu.org; Wed, 03 Jul 2019 12:20:06 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hihzG-0007Li-1n for bug-gnu-emacs@gnu.org; Wed, 03 Jul 2019 12:20:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:41121) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hihzF-0007LT-Tv for bug-gnu-emacs@gnu.org; Wed, 03 Jul 2019 12:20:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1hihzF-0003Oh-LQ for bug-gnu-emacs@gnu.org; Wed, 03 Jul 2019 12:20:01 -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, 03 Jul 2019 16:20:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 36431 X-GNU-PR-Package: emacs Original-Received: via spool by 36431-submit@debbugs.gnu.org id=B36431.156217077813027 (code B ref 36431); Wed, 03 Jul 2019 16:20:01 +0000 Original-Received: (at 36431) by debbugs.gnu.org; 3 Jul 2019 16:19:38 +0000 Original-Received: from localhost ([127.0.0.1]:49942 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hihys-0003O2-9d for submit@debbugs.gnu.org; Wed, 03 Jul 2019 12:19:38 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:7375) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hihyq-0003Nq-4P for 36431@debbugs.gnu.org; Wed, 03 Jul 2019 12:19:36 -0400 Original-Received: from pmg2.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id A99F181153; Wed, 3 Jul 2019 12:19:30 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg2.iro.umontreal.ca (Proxmox) with ESMTP id 322FF80D52; Wed, 3 Jul 2019 12:19:25 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1562170765; bh=jHp6Y69Sw8RtRfe+ST9beYzN9ovR9Kv2HtLoYw0+XFU=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=WI9hK7+dOXtSitB+57iZV2Qq1fE0Q96+EmojuZBzZQWzYhrqnY+GRIEaS5D4Q6S7L ENihcrjOqUCit4NDO+MEc/IuFLUPLhmbv2wd+dNXPSZNs47uGlIoSbjrxYeLbizKQa iNwzRLxxfuaKS7/Fz6oL19/P4Cb8SXeWdumAaRSENvTpcC7h8Mi1EPNYjM1V5bs/5Z qelFUlQecFRpXl2fMSr2C31m2UKOr3z2zP5rji3VCxEK9rCVpCA3okX+rTjnuzVG/q FgV6XmtvQfPhFzw2g7fSM9IoQxlLSqGT2D2CjwMJUa7rdKIqMMTntBgKrYkat7BiPd RvHKcPuTJ2klg== Original-Received: from pastel (76-10-141-139.dsl.teksavvy.com [76.10.141.139]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 54CBA12082E; Wed, 3 Jul 2019 12:19:23 -0400 (EDT) In-Reply-To: <83lfxfd8om.fsf@gnu.org> (Eli Zaretskii's message of "Wed, 03 Jul 2019 07:49:13 +0300") 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: 209.51.188.43 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:162025 Archived-At: > (Note that it actually only uses the byte offset's numerical value. I > couldn't find any place where it actually uses the character offset in > src_pos, it only checks its sign.) The source is required to be unibyte, so src_pos and src_pos_byte have to be equal at start and one of the two is redundant. >> There are such design comments at various places. Usually added >> after the fact, sometimes added as part of a commit-reversal to make >> sure someone else doesn't fall into the same trap ;-) > Interesting. Can you point me to a couple of such design comments? Not off-hand, no, but I know I added such comments every once in a while. >> If CODING->src_object is a buffer, it must be the current buffer. >> In this case, if CODING->src_pos is positive, it is a position of >> the source text in the buffer, otherwise, the source text is in the >> - gap area of the buffer, and CODING->src_pos specifies the offset of >> - the text from GPT (which must be the same as PT). If this is the >> - same buffer as CODING->dst_object, CODING->src_pos must be >> - negative. >> + gap area of the buffer, and CODING->src_pos specifies the >> + offset of the text from the end of the gap (which must be at PT). > > The "which must be at PT" part is ambiguous. I suggest to say > explicitly that the gap must be at PT AFAICT that's exactly what it is saying, so I'm not sure what ambiguity you're thinking of. > (although decode-coding doesn't really blindly assume that, as you can > see from its calls to move_gap_both). [ FWIW, this part of the text is mostly preserved from the old text. ] I think the issue is that decode_coding's calls to move_gap_both *must* be no-ops when the source is in the gap otherwise it'll destroy the source-text. >> + If this is the same buffer as CODING->dst_object, CODING->src_pos must >> + be negative. > I don't see the condition of the same buffer in the code. What did I > miss? This one I don't know: I just preserved this part of the text. >> + When the text is taken from the gap, it can't be at the beginning of >> + the gap so that we can produce the decoded text at the beginning of >> + the gap: this way, as the output grows, the input shrinks, so we only >> + need to allocate enough space for `max(IN, OUT)` instead of `IN + OUT`. > > I think this should also tell that decoding in this setup takes bytes > from encoded text at the end of the gap and inserts the decoded text > starting at PT, which is the same as the beginning of the gap. [ PT is both the beginning and the end of the gap ;-) ] OK, I'll clarify a bit, thanks. Stefan