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: Crash with --enable-checking and some glyphs Date: Sun, 28 Nov 2021 09:21:37 +0200 Message-ID: <83k0gsycce.fsf@gnu.org> References: <87h7c1u0cg.fsf@gnus.org> <87v90h6271.fsf@gnus.org> <83lf1d8uyw.fsf@gnu.org> <87r1b561kn.fsf@gnus.org> <871r35ziyl.fsf@gnus.org> <87sfvlwkrc.fsf_-_@gnus.org> <87sfvlh1zo.fsf@gmail.com> <87h7c0flfk.fsf@gnus.org> <874k807166.fsf@gmail.com> <87wnkwb8q7.fsf@gnus.org> <87sfvkb85w.fsf@gnus.org> <83wnkw469i.fsf@gnu.org> <87ee739kjx.fsf@gnus.org> <83h7bz2i9f.fsf@gnu.org> <87mtlrt2ei.fsf@gnus.org> <838rxb2c8i.fsf@gnu.org> <87a6hrt0ti.fsf@gnus.org> <8335ni3mr4.fsf@gnu.org> <877dctsnhz.fsf@gnus.org> <83sfvhy6mv.fsf@gnu.org> <227d35a5bcbe91bfe96c@heytings.org> <87k0gt475z.fsf@gnus.org> <227d35a5bc18f4dc6e25@heytings.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="30585"; mail-complaints-to="usenet@ciao.gmane.io" Cc: larsi@gnus.org, rpluim@gmail.com, emacs-devel@gnu.org To: Gregory Heytings Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Nov 28 08:22:25 2021 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 1mrEW0-0007f6-CX for ged-emacs-devel@m.gmane-mx.org; Sun, 28 Nov 2021 08:22:24 +0100 Original-Received: from localhost ([::1]:39056 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mrEVy-0007IB-Go for ged-emacs-devel@m.gmane-mx.org; Sun, 28 Nov 2021 02:22:22 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:60424) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mrEV8-0006QW-1n for emacs-devel@gnu.org; Sun, 28 Nov 2021 02:21:30 -0500 Original-Received: from [2001:470:142:3::e] (port=54412 helo=fencepost.gnu.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mrEV7-0002BC-AH; Sun, 28 Nov 2021 02:21:29 -0500 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=Y97kW7usmUEXjKcx2bZhIXau938HgkMpLscLXpHMwmM=; b=ovtRxBhvi8aP +o2IX+m3RYCM9AiGbPes3ZMwLmoguOuuljH6UIX7jrhbg/vmznKZWvQdR8LNE74qCq1VaSOjdUEMr ZttJurAFaq1i2LwRNPDlSCuSdmrr2Pzr5tOeJUrpLhBJ9H15NAwLrmGUL/8GGCdEzJsRyqEQ/7jgn 7lccSPBwxzwK3N4vRbXWl82a31pn5D27WLpwNhm/icDVZF/HHhnVMDc1LBnJjlRSAJqitggcORcIB b2hMF34Je7U7pnCmItW03RJhbgkV2/SQMSZ4pWCaQMZkK7T5FvNfLMrvHo5TzG4vEp82XWXGjKC8c x0LhFJk3VkT+3QnSpHxXgw==; Original-Received: from [87.69.77.57] (port=3685 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 1mrEV6-0004qM-UZ; Sun, 28 Nov 2021 02:21:29 -0500 In-Reply-To: <227d35a5bc18f4dc6e25@heytings.org> (message from Gregory Heytings on Sat, 27 Nov 2021 22:01:05 +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: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:280372 Archived-At: > Date: Sat, 27 Nov 2021 22:01:05 +0000 > From: Gregory Heytings > cc: Eli Zaretskii , rpluim@gmail.com, emacs-devel@gnu.org > > I very much doubt that this is the root cause of this bug. What do you mean by "this"? The fix that I installed didn't pretend to fix any root causes, because those are not known. I just verified that the code in that part does its job and works according to what the font metrics returned by the font backend feeds it. Since the fonts are identical, the root cause could be in the font backend (which is not our code) or maybe elsewhere. You are welcome to investigate further, but my suggestion is to start from xftfont.c and its ilk, tracing the information it returns for the font in question. The problem is also extremely rare, because otherwise everyone who builds Emacs with --enable-checking would see frequent crashes long ago. In any case, the installed fix just does what other branches of that function already did for glyphs that are not simple character glyphs, that's all. It "corrects" the ascent and descent values after they have been already used for the glyph metrics on our display, so its effect on the display should be minimal at best, and usually nil. But if you have evidence to the contrary, by all means present it, and let's see what we should and can do about that.