From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Redisplay hook error backtraces Date: Thu, 14 Jul 2022 19:47:25 +0000 Message-ID: References: <83ilo0vnwh.fsf@gnu.org> <83fsj4uvjg.fsf@gnu.org> <83mtdct5ze.fsf@gnu.org> <83bktru74y.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28670"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Eli Zaretskii , larsi@gnus.org, emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu Jul 14 21:49:15 2022 Return-path: Envelope-to: ged-emacs-devel@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 1oC4pm-0007KK-RR for ged-emacs-devel@m.gmane-mx.org; Thu, 14 Jul 2022 21:49:14 +0200 Original-Received: from localhost ([::1]:36752 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oC4pl-0004TI-IN for ged-emacs-devel@m.gmane-mx.org; Thu, 14 Jul 2022 15:49:13 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:53508) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oC4o7-0002r5-QA for emacs-devel@gnu.org; Thu, 14 Jul 2022 15:47:32 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:16603 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1oC4o3-0001XL-NU for emacs-devel@gnu.org; Thu, 14 Jul 2022 15:47:30 -0400 Original-Received: (qmail 56005 invoked by uid 3782); 14 Jul 2022 19:47:25 -0000 Original-Received: from acm.muc.de (p4fe15c93.dip0.t-ipconnect.de [79.225.92.147]) (using STARTTLS) by colin.muc.de (tmda-ofmipd) with ESMTP; Thu, 14 Jul 2022 21:47:25 +0200 Original-Received: (qmail 23643 invoked by uid 1000); 14 Jul 2022 19:47:25 -0000 Content-Disposition: inline In-Reply-To: X-Submission-Agent: TMDA/1.3.x (Ph3nix) X-Primary-Address: acm@muc.de Received-SPF: pass client-ip=193.149.48.1; envelope-from=acm@muc.de; helo=mail.muc.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:292174 Archived-At: Hello, Stefan. On Thu, Jul 14, 2022 at 12:18:51 -0400, Stefan Monnier wrote: > >> Aren't they all go through safe_call? > > They do, yes, but so do other things that we don't want to engage the > > backtrace mechanism for. > Actually, I'm not sure that's the case. Basically the question is > whether `safe_call` is used because we don't care about any errors that > might be thrown (akin to ignore-errors`) or whether we do care but don't > want to let them escape and ruin our lunch (akin to > `with-demoted-errors`). > Being in redisplay is usually a good reason why we don't want to let > errors escape, even we do care about those errors (and hence we need > to use a mechanism like the one you're implementing in order to debug > those problems), but there can be other such cases that also use > `safe_call` and where we would also want to use your new code. There are approximately 38 calls to something like safe_call in the C sources, about half of which are in xdisp.c. That's a lot of scope for irritation if non-events continually swamp the real errors in redisplay's Lisp hooks. It feels like we would want some mechanism to filter out "some" safe_call calls, and things are getting complicated fast. The scope of the exercise has already expanded considerably, from just fontification-functions to all redisplay hooks. > Stefan -- Alan Mackenzie (Nuremberg, Germany).