From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: master 7362554: Widen around c-font-lock-fontify-region. This fixes bug #38049. Date: Thu, 14 Nov 2019 21:19:03 +0200 Message-ID: <83h836466w.fsf@gnu.org> References: <20191109144026.20810.76129@vcs0.savannah.gnu.org> <20191109144027.DDC3720927@vcs0.savannah.gnu.org> <38328d99-23c8-7ba7-a23d-e70ac0aab67a@yandex.ru> <20191111203445.GA5135@ACM> <7497e71d-bab6-fa04-bbc4-f52fadeda16d@yandex.ru> <20191113211936.GB4942@ACM> <6fc930a1-eb47-9e54-8752-8cf7ff041586@yandex.ru> <03042d05-2160-77c4-9abd-b0f13f638247@yandex.ru> <83woc24ets.fsf@gnu.org> Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="184676"; mail-complaints-to="usenet@blaine.gmane.org" Cc: acm@muc.de, emacs-devel@gnu.org, dgutov@yandex.ru To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Nov 14 20:20:37 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iVKfR-000ljd-Rp for ged-emacs-devel@m.gmane.org; Thu, 14 Nov 2019 20:20:33 +0100 Original-Received: from localhost ([::1]:60996 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iVKfQ-0005YF-JB for ged-emacs-devel@m.gmane.org; Thu, 14 Nov 2019 14:20:32 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55617) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iVKeK-0005XN-Q5 for emacs-devel@gnu.org; Thu, 14 Nov 2019 14:19:26 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:58158) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1iVKeH-0008WE-70; Thu, 14 Nov 2019 14:19:22 -0500 Original-Received: from [176.228.60.248] (port=3896 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1iVKeG-0004VZ-HY; Thu, 14 Nov 2019 14:19:20 -0500 In-reply-to: (message from Stefan Monnier on Thu, 14 Nov 2019 13:51:05 -0500) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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:242193 Archived-At: > From: Stefan Monnier > Cc: dgutov@yandex.ru, acm@muc.de, emacs-devel@gnu.org > Date: Thu, 14 Nov 2019 13:51:05 -0500 > > >> So, your earlier patch which added a call to `font-lock-ensure` was > >> "more or less right", except that it should have used > >> `jit-lock-ensure` (currently called `jit-lock-fontify-now`) and > >> could have a comment explaining that vertical-motion will trigger > >> jit-lock anyway so it's better to do it once beforehand on the whole > >> region, not only so it can be done outside of the narrowing but also > >> so it can be done more efficiently than one jit-lock-chunk-size at a > >> time. > > I'd like to solve this in CC mode instead, because the problem is there. > > I think the problem is wider than CC-mode. Maybe CC-mode is more > susceptible to it or maybe it's just an accident that this was reported > for CC-mode, but running font-lock (and syntax-propertize) within > narrowing tends to be fiddly. I'm also okay with fixing it in font-lock or jit-lock. But doing that inside reposition.el makes no sense to me. > > Fontifying arbitrary portions of the buffer to indirectly > > avoid triggering the problem in CC mode sounds not TRT to me. > > `vertical-motion` *will* call `jit-lock-fontify-now` on all those buffer > positions in any case, so while it is extra code I'd rather we don't need > to write, it shouldn't have a negative impact on performance, quite the > contrary. So we are going to do such changes in every application that calls vertical-motion, directly or indirectly? And what about posn-at-point, or pos-visible-in-window-p, or any other API that uses the display code internally? are we going to fix their callers as well? That really makes no sense, so I very much hope I somehow grossly misunderstand what you are suggesting as a fix. > > In particular, what if the POINT-MIN..END chunk is still too large to > > fontify in one go? > > AFAIK all uses of jit-lock are more efficient if they get fewer larger > chunks than more smaller chunks. So you are saying that we should enlarge jit-lock-chunk-size to most-positive-fixnum? I don't think so.