From owner-cvs-all@FreeBSD.ORG Tue Aug 28 02:39:13 2007 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7907916A420; Tue, 28 Aug 2007 02:39:13 +0000 (UTC) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (comp.chem.msu.su [158.250.32.97]) by mx1.freebsd.org (Postfix) with ESMTP id 7469E13C457; Tue, 28 Aug 2007 02:39:11 +0000 (UTC) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (localhost [127.0.0.1]) by comp.chem.msu.su (8.13.4/8.13.4) with ESMTP id l7S2cvmb085139; Tue, 28 Aug 2007 06:38:57 +0400 (MSD) (envelope-from yar@comp.chem.msu.su) Received: (from yar@localhost) by comp.chem.msu.su (8.13.4/8.13.4/Submit) id l7S2cv7J085138; Tue, 28 Aug 2007 06:38:57 +0400 (MSD) (envelope-from yar) Date: Tue, 28 Aug 2007 06:38:57 +0400 From: Yar Tikhiy To: Daniel Eischen Message-ID: <20070828023857.GW21352@comp.chem.msu.su> References: <200708270850.20904.jhb@freebsd.org> <200708271715.21462.jhb@freebsd.org> <200708271757.01674.jhb@freebsd.org> <20070828004842.GT21352@comp.chem.msu.su> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i Cc: src-committers@freebsd.org, John Baldwin , alfred@freebsd.org, cvs-all@freebsd.org, cvs-src@freebsd.org, "M. Warner Losh" Subject: Re: cvs commit: src/lib/libc/gen fts-compat.c fts-compat.h X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Aug 2007 02:39:13 -0000 On Mon, Aug 27, 2007 at 09:30:48PM -0400, Daniel Eischen wrote: > On Tue, 28 Aug 2007, Yar Tikhiy wrote: > > > >Example: Assume we released 7.0-R with all symbols at FBSD_1.0. > >Before the 8.0 release cycle starts, struct FTS and struct FILE > >change, perhaps a few times each, thus affecting the fts(3) and > >stdio(3) global symbols. At the very first change to a symbol or > >their group, its 7.0-R variant is preserved at FBSD_1.0 and its > >default version becomes FBSD_1.1. Later changes to the current > >variant of that symbol don't affect its version. Consequently, > >8.0-R is released with the new fts(3) and stdio(3) symbols at > >FBSD_1.1, their 7.0-R variants at FBSD_1.0, and the rest of symbols > >still at FBSD_1.0 because they are unchanged. Let's note that > >CURRENT users had to rebuild ports depending on fts(3) or stdio(3) > >_each time_ an ABI component changed. > > I think you're a little confused here. CURRENT users did NOT have > to rebuild ports when fts(3) or stdio(3) ABIs changed. They > would only have to rebuild if one of these ABIs changed _more > than once between releases_. That hasn't ever happened to my > knowledge in the past, and it really shouldn't happen as long > as things are tested and reviewed properly. Oh, indeed! If a user builds an ABI-dependent port before the change, the port will record dependence on say fwrite@FBSD_1.0. In our example, the default version of fwrite() and friends will change to FBSD_1.1 later, after 7.0-RELEASE is out, but fwrite@FBSD_1.0 will also stay as a compatibility version because it appeared in the previous release. Moreover, the port will still work even if the ABI component changes once more after 8.0-RELEASE and proceeds to FBSD_1.2, because fwrite@FBSD_1.0 will be there. Similarly, a port built between 7.0-R and 8.0-R will work after the 2nd change as fwrite@FBSD_1.1 will be there, too. I can't but remark that this is not a natural effect of symbol versioning, but a consequence from the following policy: - At most one new version is introduced between major releases. - Symbol modifications during the period are assigned to the new version. - There is exactly one change per symbol per version. - All old symbol versions created so far are preserved. Now we have at least one policy with known behavior. :-) -- Yar