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.bugs Subject: bug#51577: 27.2; Regression: reproducible hang with face functions Date: Thu, 04 Nov 2021 21:01:59 +0200 Message-ID: <83y263eod4.fsf@gnu.org> References: <83tugtgo6z.fsf@gnu.org> <83a6ilgh37.fsf@gnu.org> <87bl2zss78.fsf_-_@gnus.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="34355"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 51577@debbugs.gnu.org To: Lars Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Nov 04 20:03:15 2021 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1mii15-0008ef-7e for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 04 Nov 2021 20:03:15 +0100 Original-Received: from localhost ([::1]:36746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mii13-0005n4-BS for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 04 Nov 2021 15:03:13 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40840) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mii0s-0005mr-FG for bug-gnu-emacs@gnu.org; Thu, 04 Nov 2021 15:03:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:60268) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1mii0s-0000fs-6c for bug-gnu-emacs@gnu.org; Thu, 04 Nov 2021 15:03:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1mii0s-0006Hr-38 for bug-gnu-emacs@gnu.org; Thu, 04 Nov 2021 15:03:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 04 Nov 2021 19:03:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 51577 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: moreinfo notabug Original-Received: via spool by 51577-submit@debbugs.gnu.org id=B51577.163605253524098 (code B ref 51577); Thu, 04 Nov 2021 19:03:02 +0000 Original-Received: (at 51577) by debbugs.gnu.org; 4 Nov 2021 19:02:15 +0000 Original-Received: from localhost ([127.0.0.1]:43581 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mii07-0006Gc-KQ for submit@debbugs.gnu.org; Thu, 04 Nov 2021 15:02:15 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:43142) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1mii06-0006GQ-50 for 51577@debbugs.gnu.org; Thu, 04 Nov 2021 15:02:14 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:52590) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mii00-0000Sl-F4; Thu, 04 Nov 2021 15:02:08 -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=lez7rem3TtPUpe2v9hWeoOcyjBsxiXf4wLkoIILhUo4=; b=sSRQjhwrLI0P atgARqjGNoewrGflj7bL1OmgQ0U07ESwN2J61mc4ldoDyaPsGxNGPqS6EfgAKgrVfwZ7hbiFAqfi0 xOqznpLzFs+RIse3rt6j/IiOi/O5ya+g46sJPxILqg5DBlLKqCfIwZZfxOW3SFcOIREdgYAE+2P7v V2N+P8GywTtMqV1PnO3T+DXHkDfIlh7TeQDCrCtkH6mQdWTswYaNoqM2KRRsKa59Uc+tqL5nLZ1BJ JAuSu7qWJAggpQv/zg34zHPkzPPla7PsNkOqDMve7ayY0uig8wWDN4Q+XB4LcwhQW5oYVX9yzZfKA d1H86Zx3t0c9jYQudSuGrQ==; Original-Received: from [87.69.77.57] (port=1850 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 1mihzw-0007Cq-BA; Thu, 04 Nov 2021 15:02:08 -0400 In-Reply-To: <87bl2zss78.fsf_-_@gnus.org> (message from Lars Ingebrigtsen on Thu, 04 Nov 2021 19:15:23 +0100) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:218938 Archived-At: > From: Lars Ingebrigtsen > Cc: Drew Adams , 51577@debbugs.gnu.org > Date: Thu, 04 Nov 2021 19:15:23 +0100 > > Eli Zaretskii writes: > > > And how does your code differ from this: > > > > (while t nil) > > > > Or would you consider it a bug that Emacs doesn't detect the infinite > > while-loop, either? > > We do try to detect loops in other situations (to avoid hangs). This is > in redisplay code, though (I think?), so perhaps it would be > prohibitively expensive to try to detect loops here? First, since this is triggered by redisplay, any errors must be "silent": we log an error message in *Messages* and otherwise silently do nothing. Which in this case would mean the problematic face will not be applied. Not sure this is better than inflooping. As for detecting loops: it could be tricky. It is easy enough to detect simple loops such as the one in this case, where a face inherits directly from itself, and the value of the :inherit attribute is the symbol of a face. But inheritance loops could be less simple: a face could inherit from itself indirectly, and the value of the attribute could be a list, not a named face. Detecting loops in those cases would require recording face specs/names we already saw in some list, and each time we get an :inherit attribute, check if its value is already in the list. Is that worth our while, if the result will be a silent error message in *Messages*?