Gentoo Archives: gentoo-pms

From: Ciaran McCreesh <ciaran.mccreesh@××××××××××.com>
To: gentoo-pms@l.g.o
Subject: Re: [gentoo-pms] Do we want an EAPI 5?
Date: Fri, 01 Jul 2011 06:15:32
Message-Id: 20110701071238.17dee2b8@googlemail.com
In Reply to: Re: [gentoo-pms] Do we want an EAPI 5? by Sebastian Luther
On Thu, 30 Jun 2011 20:48:46 +0200
Sebastian Luther <SebastianLuther@×××.de> wrote:
> > Portage's behaviour is already broken there -- think what happens > > when ebuilds get removed. > > I know. I'm not opposed to this change, but the needed work flow > change for ebuild devs has to be communicated.
Shouldn't be a workflow change. It's already policy to do a revbump if dependencies change.
> >> Could you please give a summary (or point me to one) of the > >> discussion about :=/:*? > > > > See the original EAPI 3 discussion. It's all there. > > > Yeah, the whole discussion is there, but not a summary. I don't have > the time to wade through all these mails.
Part of the reason EAPI 3 dragged on for so long was that rather than reading the discussion, people would say "I've not read the entire thread, but it seems to me that ...", and then the entire discussion would have to be repeated all over again. If you're just looking for a summary, not details: say a user has cat/dep:1, cat/dep:2 and cat/dep:3 installed, and wants to uninstall cat/dep:1 and cat/dep:2. Say there's cat/pkg installed which has a dep upon cat/dep. Then there's no way for the package mangler to know which cat/dep slots are still 'needed', and which can be safely removed. Thus, to be safe, it has to assume that all three slots might be needed. Nearly all packages that dep upon a slotted dependent have one of two behaviours: they're ok with any slot that matches the rest of the spec (including switching at runtime), or they need the best slot that was present at install time. The former is :*, the latter :=. There are a few perverse cases that don't fit these. Those need special fancy handling, and they're sufficiently fiddly that we shouldn't be holding up solving the large number easy cases to deal with one or two weird packages.
> Isn't it desirable that different PMs handle the "no operator" case in > the same way (independently of the question of having one or both > operators available)?
The problem is that every way of handling the "no operator" case is wrong for many real situations. You can assume either "any slot" or "best slot", both of which will allow packages to be removed unsafely, or you can assume "all slots", which is excessively paranoid for many packages. -- Ciaran McCreesh

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Re: [gentoo-pms] Do we want an EAPI 5? Sebastian Luther <SebastianLuther@×××.de>