From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Edebug corrupting point in buffers. Date: Wed, 02 Nov 2022 18:57:39 +0200 Message-ID: <83cza59tvg.fsf@gnu.org> References: <83iljydh7e.fsf@gnu.org> <838rkud9d5.fsf@gnu.org> <83v8nybnuk.fsf@gnu.org> <83pme6bls8.fsf@gnu.org> <83mt99a223.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="30266"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Alan Mackenzie Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Nov 02 17:59:07 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 1oqH50-0007dY-Kz for ged-emacs-devel@m.gmane-mx.org; Wed, 02 Nov 2022 17:59:06 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oqH3o-0005xC-UH; Wed, 02 Nov 2022 12:57:52 -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 1oqH3l-0005uo-Pf for emacs-devel@gnu.org; Wed, 02 Nov 2022 12:57:49 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oqH3l-0001Wi-07; Wed, 02 Nov 2022 12:57:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=C9phoS1XIJ5tlDaUo/+9rEr1AJT5dBJbeJOhhvKQah0=; b=O3sHtpjhHysy KaoDCuJfjdii5s8mpr906fRnPxstlGFjgJwm/HeW40+4o8li7GB/Svjb9IuaBLTw5dwmw6L7ZnlQ1 Zny/Dz302krdNEE5P63Wj4ZhZsBrdjPFKeX1phuyhUfOdG/o9Q7+uLezADfsvTJ7Ih+5VomJDVf10 Wxi7buSJQ06VCSKP16D6I22mJfv9zO9ie4Z6T9xwEXbska7qQbAbLMMURkTVnIThS1QSppJv5g6uP XtHf29+JldqiwrIRuFkvcUNefE94bZimQ7L/iWZU68toWraeX0tHv7u7z20CGdaoFXxz0F4qwkWvI kE09S3f5YNa2TIV3GwgEAg==; Original-Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oqH3k-0006z4-Eu; Wed, 02 Nov 2022 12:57:48 -0400 In-Reply-To: (message from Alan Mackenzie on Wed, 2 Nov 2022 16:18:24 +0000) 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: , Original-Sender: "Emacs-devel" Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:299028 Archived-At: > Date: Wed, 2 Nov 2022 16:18:24 +0000 > Cc: emacs-devel@gnu.org > From: Alan Mackenzie > > > Yes, I see the problem, but setting edebug-save-windows to nil > > eliminates it. So I think we already have a solution for the rare > > situations where this is an issue. > > It remains a perplexing problem for those who stumble into it. How about > instead of patching the code, adding some documentation clarifying the > problem? > > I would propose the following: Fine by me, but... > diff --git a/doc/lispref/edebug.texi b/doc/lispref/edebug.texi > index 6a51489d8a..b4f680fe86 100644 > --- a/doc/lispref/edebug.texi > +++ b/doc/lispref/edebug.texi > @@ -1019,6 +1019,7 @@ The Outside Context > @menu > * Checking Whether to Stop:: When Edebug decides what to do. > * Edebug Display Update:: When Edebug updates the display. > +* Edebug Buffer Points:: When @code{point} gets corrupted. > * Edebug Recursive Edit:: When Edebug stops execution. > @end menu ...please document this in the same place where the variables we discussed are described. It is not a good idea from the didactic POV to have this described separately. > +This can be a problem when your program itself sets point in a buffer, > +intending later to use that value of point. For example, suppose you > +have buffer B displayed in your selected frame, and you step through > +the following Lisp fragment: > + > +@example > +(set-buffer A) > +(set-buffer B) > +(goto-char (point-max)) > +(insert "foo") > +(set-buffer A) > +(set-buffer B) > +(insert "bar") > +@end example I very much doubt that showing this example will help. It just muddies the water, b y forcing users to try to understand what the example does, which is completely irrelevant to what we want to convey. Just say that if point gets reset in non-selected windows during Edebug stepping, users should try customizing that variable.