From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Unbalanced change hooks (part 2) [Documentation fix still remaining] Date: Tue, 30 Aug 2016 18:08:12 +0300 Message-ID: <83fupmnvkz.fsf@gnu.org> References: <20160810161821.GB3413@acm.fritz.box> <83wpjofttf.fsf@gnu.org> <20160810185735.GD3413@acm.fritz.box> <20160811112951.GA2154@acm.fritz.box> <7e1478b6-cf00-fcbf-8c24-43bdaa57e2b6@dancol.org> <415d1cca-f32c-624e-a4be-9aadcf8a0f17@dancol.org> <83inujbpek.fsf@gnu.org> <83eg57bl8f.fsf@gnu.org> <5ee6ff4a-2d58-82f1-8e83-479c62f0b729@dancol.org> <837fazbjb4.fsf@gnu.org> <75100b15-d49f-5a1a-d73b-24db77c891bf@dancol.org> <831t17bged.fsf@gnu.org> <83shtn9e0z.fsf@gnu.org> <341353e9-8388-103b-7c45-3c2a667081c5@dancol.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1472569822 5593 195.159.176.226 (30 Aug 2016 15:10:22 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 30 Aug 2016 15:10:22 +0000 (UTC) Cc: monnier@IRO.UMontreal.CA, emacs-devel@gnu.org To: Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 30 17:10:14 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bekg1-0000aN-1r for ged-emacs-devel@m.gmane.org; Tue, 30 Aug 2016 17:10:13 +0200 Original-Received: from localhost ([::1]:49597 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bekfy-0002ip-Ja for ged-emacs-devel@m.gmane.org; Tue, 30 Aug 2016 11:10:10 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:55898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bekeG-0001qm-J2 for emacs-devel@gnu.org; Tue, 30 Aug 2016 11:08:25 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1beke9-00026v-Vx for emacs-devel@gnu.org; Tue, 30 Aug 2016 11:08:23 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:55279) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1beke9-000265-Rz; Tue, 30 Aug 2016 11:08:17 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1663 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1beke7-0003Ff-UV; Tue, 30 Aug 2016 11:08:16 -0400 In-reply-to: <341353e9-8388-103b-7c45-3c2a667081c5@dancol.org> (message from Daniel Colascione on Mon, 29 Aug 2016 19:54:52 -0700) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:206938 Archived-At: > Cc: emacs-devel@gnu.org > From: Daniel Colascione > Date: Mon, 29 Aug 2016 19:54:52 -0700 > > On 08/29/2016 07:38 PM, Eli Zaretskii wrote: > >> From: Stefan Monnier > >> Cc: Daniel Colascione , emacs-devel@gnu.org > >> Date: Mon, 29 Aug 2016 20:25:06 -0400 > >> > >>>> #1 breaks the entire b-c-f model --- "hey, I'm about to modify the > >>>> buffer, so throw away caches" ---- and can lead to anything with a > >>>> cache flush in b-c-f (like syntax-ppss) not properly discarding > >>>> out-of-date buffer information. > >>> That single case of #1 is revert-buffer, which conceptually throws > >>> away the entire buffer and replaces it with what's on disk. That it > >>> actually keeps portions of the buffer is an optimization, but the > >>> concept still stands. So I don't see how it breaks the entire model, > >>> at least not in practice. > >> > >> The optimization is beside the point: not calling b-c-f in some corner > >> case breaks the entire model because a user such as syntax-ppss relies > >> on b-c-f to know when to flush its cache, so if you don't call it when > >> the buffer is modified, the cache ends up stale. > > > > I'm saying that flushing the entire cache in that case is not a > > problem, it's what needs to be done anyway. > > How is a mode supposed to know that it's supposed to flush its cache? I think I misunderstood you, sorry. I thought you were saying that in the absence of the before-change call a mode will decide to flush its caches, and that you've considered such flushing a problem of some sort.