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 19:33:09 +0000 Message-ID: References: <83ilo0vnwh.fsf@gnu.org> <83fsj4uvjg.fsf@gnu.org> <83mtdct5ze.fsf@gnu.org> <83bktru74y.fsf@gnu.org> <831quntydt.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="34978"; mail-complaints-to="usenet@ciao.gmane.io" Cc: larsi@gnus.org, monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu Jul 14 21:34:24 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 1oC4bQ-0008sx-9m for ged-emacs-devel@m.gmane-mx.org; Thu, 14 Jul 2022 21:34:24 +0200 Original-Received: from localhost ([::1]:53516 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oC4bO-0004Rl-Tx for ged-emacs-devel@m.gmane-mx.org; Thu, 14 Jul 2022 15:34:22 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:50626) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oC4aK-0003Kz-UJ for emacs-devel@gnu.org; Thu, 14 Jul 2022 15:33:16 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:16257 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.90_1) (envelope-from ) id 1oC4aH-0007bF-Dg for emacs-devel@gnu.org; Thu, 14 Jul 2022 15:33:16 -0400 Original-Received: (qmail 47151 invoked by uid 3782); 14 Jul 2022 19:33:09 -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 21:33:09 +0200 Original-Received: (qmail 23596 invoked by uid 1000); 14 Jul 2022 19:33:09 -0000 Content-Disposition: inline In-Reply-To: <831quntydt.fsf@gnu.org> 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=ham 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:292171 Archived-At: Hello, Eli. On Thu, Jul 14, 2022 at 20:09:02 +0300, Eli Zaretskii wrote: > > Date: Thu, 14 Jul 2022 16:07:33 +0000 > > Cc: larsi@gnus.org, monnier@iro.umontreal.ca, emacs-devel@gnu.org > > From: Alan Mackenzie > > > There's just one condition-case available to Lisp code, AFAICT, so why > > > isn't it enough to distinguish condition-case from any other callers of > > > internal_condition_case* ? > > I think I understand what you're saying, now. That a condition-case > > called from Lisp will not use any of the internal_condition_case* > > functions. So we could just assume that if i_c_case* triggers, it must be > > one of the hooks we're interested in that called it. > > I don't think that's right. It might well be that Lisp code calls a C > > primitive function that itself uses an internal_condition_case. In this > > scenario, we would not want to generate a backtrace for that nested > > internal_condition_case. > And we won't, because redisplaying_p won't be set. I don't understand. If redisplay is called normally, it will go through redisplay_internal which sets redisplaying_p to true. And it will stay true till the end of redisplay_internal, unless one of two special things happen: (i) We enter the debugger; (ii) there's a recursive edit. I don't see how the new backtrace facility can get any useful information out of redisplaying_p; if there were a nested internal_condition_case*, redisplaying_p would still be true, surely? What am I missing? > > > > I disagree. There are seven places, for the seven different Lisp hooks > > > > currently called from redisplay. > > > 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. > > > Which seven places are you talking about? > > 1. handle_fontified_prop; > > 2. set_message; > > 3. clear_message; > > 4. prepare_menu_bars (near the top); > > 5. update_menu_bar (line ~54); > > 6. run_window_scroll_functions; > > 7. redisplay_window (line ~415). > These either go through safe__call, or through run_hook_with_args. I > think the latter group should be converted to call safe__call and its > friends. And then you will have what I described: all those calls go > through a single gate. Maybe tomorrow! -- Alan Mackenzie (Nuremberg, Germany).