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 05:38:52 +0300 Message-ID: <83shtn9e0z.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> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1472524750 29160 195.159.176.226 (30 Aug 2016 02:39:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 30 Aug 2016 02:39:10 +0000 (UTC) Cc: dancol@dancol.org, emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 30 04:39:05 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 1beYx7-000720-C2 for ged-emacs-devel@m.gmane.org; Tue, 30 Aug 2016 04:39:05 +0200 Original-Received: from localhost ([::1]:46608 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1beYx4-0000xd-Q9 for ged-emacs-devel@m.gmane.org; Mon, 29 Aug 2016 22:39:02 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:34155) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1beYwz-0000xM-9K for emacs-devel@gnu.org; Mon, 29 Aug 2016 22:38:58 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1beYwv-0008Tk-5G for emacs-devel@gnu.org; Mon, 29 Aug 2016 22:38:56 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:46945) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1beYwv-0008Tf-1c; Mon, 29 Aug 2016 22:38:53 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:2802 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1beYwt-0002gE-8B; Mon, 29 Aug 2016 22:38:51 -0400 In-reply-to: (message from Stefan Monnier on Mon, 29 Aug 2016 20:25:06 -0400) 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:206913 Archived-At: > 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.