From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id DF6D9138010 for ; Thu, 6 Sep 2012 06:02:58 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 436E0E0683 for ; Thu, 6 Sep 2012 06:02:58 +0000 (UTC) Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) by pigeon.gentoo.org (Postfix) with ESMTP id 80585E0566 for ; Thu, 6 Sep 2012 04:38:36 +0000 (UTC) Received: from [192.168.26.5] (ip98-164-193-252.oc.oc.cox.net [98.164.193.252]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: zmedico) by smtp.gentoo.org (Postfix) with ESMTPSA id E8A5533D765; Thu, 6 Sep 2012 04:38:35 +0000 (UTC) Message-ID: <504828CA.6040607@gentoo.org> Date: Wed, 05 Sep 2012 21:38:34 -0700 From: Zac Medico User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:15.0) Gecko/20120901 Thunderbird/15.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Project discussion list X-BeenThere: gentoo-project@lists.gentoo.org Reply-To: gentoo-project@lists.gentoo.org MIME-Version: 1.0 To: gentoo-project@lists.gentoo.org CC: Fabian Groffen Subject: Re: [gentoo-project] [sub-slot] List of features proposed for EAPI 5 References: <20549.54500.967226.363097@a1i15.kph.uni-mainz.de> <20549.55773.850891.258667@a1i15.kph.uni-mainz.de> <20120905195918.GJ5282@gentoo.org> In-Reply-To: <20120905195918.GJ5282@gentoo.org> X-Enigmail-Version: 1.4.4 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Archives-Salt: 2519a303-a4a6-466d-a15d-33c53deda3de X-Archives-Hash: 16315b0883111f89a0d8b7b4542b9c37 On 09/05/2012 12:59 PM, Fabian Groffen wrote: > Seems I was to quick with the previous mail. > > On 04-09-2012 12:37:17 +0200, Ulrich Mueller wrote: >> * Sub-slots >> PMS wording: >> Portage patch: >> Bug: > > Any pointers where we can find the argumentation what this is useful > for? It was discussed in the "About forcing rebuilds of other packages issue" [1] thread on the gentoo-dev mailing list. > PMS is very terse when it writes: > > The sub-slot is used to represent cases in which an upgrade to a new > version of a package with a different sub-slot may require dependent > packages to be rebuilt. When the sub-slot part is omitted from the > SLOT definition, the package is considered to have an implicit > sub-slot which is equal to the regular slot. > > While this is an inconsistency, as pointed out in previous email, it is > unclear to me how this feature distinguishes from the general slot > operator dependencies, which appears to achieve the same. The difference is that it's possible for the sub-slot to change while the regular slot remains constant. I'm sure that you're familiar with FEATURES=preserve-libs, and sub-slots can be used to trigger automatic rebuilds in every case that triggers preserve-libs. I gave some examples of how automatic rebuilds behave in my blog post about EAPI 4-slot-abi [2]. In the comments of that post, I also mentioned that automatic rebuilds are preferable to using @preserved-rebuild, since then help to avoid the possibility of symbol collisions [3]. Another issue with @preserved-rebuild is that it pulls in possibly irrelevant packages that are eligible for removal by --depclean. Automatic rebuilds triggered by sub-slot changes to do not suffer from this problem. > My impression here is that this tries to work around a problem where > SLOT != ABI. If (and that is what I assume here) the sub-slot is used > to have a major/minor-like matching criteria, it would've been more > native to use dev-libs/glib:2.* and a sole slot of "2.30". > In the end, it seems to be necessary to identify the various cases of > breakage using versioned ELF objects, based on libtool's versioning > rules, and use those as starting point to backup this feature. (Taking > special care for downgrading.) We already discussed various kinds of syntax in the "About forcing rebuilds of other packages issue" thread, and everyone seemed to be happy with the sub-slot syntax that Ciaran suggested [4]. It's been tested in the axs overlay for things like perl and icu sub-slot ABI changes, and seems to work well. [1] http://thread.gmane.org/gmane.linux.gentoo.devel/77601 [2] http://blogs.gentoo.org/zmedico/2012/06/23/automatic-rebuilds-with-experimental-eapi-4-slot-abi/ [3] http://blog.flameeyes.eu/2008/06/a-few-risks-i-see-related-to-the-new-portage-2-2-preserve-libs-behaviour [4] http://archives.gentoo.org/gentoo-dev/msg_f0e171be0f12abac2a10069e05e43c73.xml [5] https://bugs.gentoo.org/424429 -- Thanks, Zac