From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eric Abrahamsen Newsgroups: gmane.emacs.help Subject: Re: debug-ignored-errors usage Date: Thu, 02 May 2019 21:33:50 -0700 Message-ID: <87sgtwf975.fsf@ericabrahamsen.net> References: <86ef5gw97l.fsf@zoho.eu> <874l6ci60b.fsf@ericabrahamsen.net> <86a7g4w4t0.fsf@zoho.eu> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="67540"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri May 03 06:34:10 2019 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hMPti-000HQg-4f for geh-help-gnu-emacs@m.gmane.org; Fri, 03 May 2019 06:34:10 +0200 Original-Received: from localhost ([127.0.0.1]:34252 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hMPtg-0002Hx-CD for geh-help-gnu-emacs@m.gmane.org; Fri, 03 May 2019 00:34:08 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:42800) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hMPtX-0002Hq-LQ for help-gnu-emacs@gnu.org; Fri, 03 May 2019 00:34:00 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hMPtW-0000Tv-MO for help-gnu-emacs@gnu.org; Fri, 03 May 2019 00:33:59 -0400 Original-Received: from [195.159.176.226] (port=44554 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hMPtW-0000T4-G5 for help-gnu-emacs@gnu.org; Fri, 03 May 2019 00:33:58 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.89) (envelope-from ) id 1hMPtU-000H5m-CA for help-gnu-emacs@gnu.org; Fri, 03 May 2019 06:33:56 +0200 X-Injected-Via-Gmane: http://gmane.org/ Cancel-Lock: sha1:nYVZ8OuqTgeW79g1lg8tmabwoxU= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:120154 Archived-At: Emanuel Berg writes: > Eric Abrahamsen wrote: > >> The docstring explains it: these are errors >> that _won't_ trigger the debugger even if >> you've toggled debug-on-error t. > > This > > (/ 1 0) > > triggers the error (arith-error) for me but the > second time I do it it just says "Arithmetic > error" in the minibuffer. And the third time > etc ... > > So the debugger is only triggered once per > error type? Is this why I never see the > debugger half-window despite not doing anything > to not see it? I just have Emacs on and before > long there aren't any errors I haven't > seen already? > > Also, putting beginning-of-buffer in > `debug-ignored-errors' still echoes > "Beginning of buffer" in the minibuffer when > that happens. > > So what does it really achieve: you don't get > the debugger window _the first time either_, > but you still get the message every time > like always? > > Because perhaps that message is not part of the > actual error? Which, if so, is wierd, because > from the name of the error, and spelling of the > message, it sure sounds like they are a pretty > close match! It means that if you've run `toggle-debug-on-error', and then one of those errors occurs, you _won't_ get the debug window popping up, which normally all errors would do. Some errors are basic enough or common enough that Emacs assuming you don't need to see a debug window for them. For instance, beginning-of-buffer. I can toggle debug on error to t, put point at the beginning of a buffer, and hit backward-char. That's actually an error, though all you see is the message in the minibuffer. If the beginning-of-buffer symbol were not in `debug-ignored-errors', it would pop up a *Debug* window showing me the error backtrace. But there's really no point in seeing a backtrace for beginning-of-buffer. Emanuel Berg writes: > Eric Abrahamsen wrote: > >> Your value looks very much like ispell or >> some other spelling package has added it's >> own regexp in there to skip debugging when it >> couldn't find a word to check. > > But why does ispell produce an error at all, if > it automatically on installation tells Emacs to > ignore it? It just tells Emacs that, even if `debug-on-error' is true, the user doesn't really need to see the debug window if there's no word to check. There's no "deeper information" to be gleaned from a backtrace. Eric