From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Warning on files byte-compiled with different versions Date: Sun, 14 Feb 2016 12:15:43 -0500 Message-ID: References: <87mvr7nxu4.fsf@russet.org.uk> <87pow2c956.fsf@russet.org.uk> <87a8n39vy2.fsf@linux-m68k.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1455470182 9883 80.91.229.3 (14 Feb 2016 17:16:22 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 14 Feb 2016 17:16:22 +0000 (UTC) Cc: emacs-devel@gnu.org To: Andreas Schwab Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sun Feb 14 18:16:13 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aV0HJ-0001ub-Us for ged-emacs-devel@m.gmane.org; Sun, 14 Feb 2016 18:16:10 +0100 Original-Received: from localhost ([::1]:52181 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aV0HF-0006B7-SB for ged-emacs-devel@m.gmane.org; Sun, 14 Feb 2016 12:16:05 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:34132) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aV0H2-0006Ay-6r for emacs-devel@gnu.org; Sun, 14 Feb 2016 12:15:53 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aV0Gx-0002cI-7J for emacs-devel@gnu.org; Sun, 14 Feb 2016 12:15:52 -0500 Original-Received: from pruche.dit.umontreal.ca ([132.204.246.22]:49574) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aV0Gx-0002c0-0F for emacs-devel@gnu.org; Sun, 14 Feb 2016 12:15:47 -0500 Original-Received: from fmsmemgm.homelinux.net (lechon.iro.umontreal.ca [132.204.27.242]) by pruche.DIT.UMontreal.CA (8.14.1/8.14.1) with ESMTP id u1EHFeWc012855; Sun, 14 Feb 2016 12:15:41 -0500 Original-Received: by fmsmemgm.homelinux.net (Postfix, from userid 20848) id F11CCAE127; Sun, 14 Feb 2016 12:15:43 -0500 (EST) In-Reply-To: <87a8n39vy2.fsf@linux-m68k.org> (Andreas Schwab's message of "Sun, 14 Feb 2016 16:02:29 +0100") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1.50 (gnu/linux) X-NAI-Spam-Flag: NO X-NAI-Spam-Threshold: 5 X-NAI-Spam-Score: 0 X-NAI-Spam-Rules: 1 Rules triggered RV5581=0 X-NAI-Spam-Version: 2.3.0.9418 : core <5581> : inlines <4325> : streams <1587507> : uri <2141556> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 132.204.246.22 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:199937 Archived-At: > contains multi-byte characters. Just because the file was compiled by a > later version should not be a reason to prevent loading it, only if the > format itself changes. In practice, it's common to bump into problems for a file compiled with a later version. Usually it's because of macros, tho there are other cases (e.g. the new bytecodes in 24.1 used for lexical-binding code, or the new byte-codes (introduced in 24.4 and used since 25.1) used to compile condition-case more efficiently in lexical-binding). It's just much easier to say there's no forward compatibility, even if it will sometime work fine. Note also that we're talking about signaling a warning, not an error. Stefan