From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id AC983139694 for ; Thu, 15 Jun 2017 16:45:20 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 9AB1F21C1D6; Thu, 15 Jun 2017 16:45:14 +0000 (UTC) Received: from mail-wr0-x243.google.com (mail-wr0-x243.google.com [IPv6:2a00:1450:400c:c0c::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 3121721C054 for ; Thu, 15 Jun 2017 16:45:14 +0000 (UTC) Received: by mail-wr0-x243.google.com with SMTP id x23so4291104wrb.0 for ; Thu, 15 Jun 2017 09:45:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20161025; h=date:from:to:subject:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=xXHIdGIQb56GKtcLL9wAsZ39Ys4uU7ZCoOLnlVxb8J8=; b=OecLHIbfJdJ0ge7bio0xHRCLcwqn5YhMlSU6/IV4MP9jMf8hnh+MbxTWF5yUQweqRo i9/yz4wJdWAHgA9JDPS0NCSbxKDtaP+cbbvuFPJkyHdK0zzIw7iRahEYwfB9S+4q0ehb ojiAU9I1RgtbQTTPCaR+7PY8DnTFq06i4F//y2noH9jzqpNcaAyo1OxGnZOiuj2vABH0 ekFvLqZQO10alZqgZ1HGGGF/Z1ljZoPb7HtjxKb1E7agMVb8aBqrBnR8GTV7jre//9x9 bnaKU4HesLjLsSmAWct3bXxC158xMmCT+5FX1GaAn1HBAl/b3TUvMwm0GOb+U9ui+1TT fqEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=xXHIdGIQb56GKtcLL9wAsZ39Ys4uU7ZCoOLnlVxb8J8=; b=kOKTJ2bNBfLSxfaTlrTtzjrYkK52STU0P5dztPJqB6pfqvu+BeLMzEMeL3dvs29Ijl QZQsi5sXxTUmJGwsO0SNKcLggbH26stNf3nrMFrXEZX8Sq+NRUWcsQmCWS+B+XBQ7pHk hKqnebvKH5nPKEgW0ZLks7zLavT3G21kJODHY49gH+ZMDhPiegPzfwQGfvDRb08QK0w3 qgENn/6EsFjty/9K7PzfkXU2LFLlz5qzB0bhlXkeesYajpi7cwRzeAiWjfj4PXvx+DZS Gzmb87VGDaDPaH88ggoi2hL7LzZNXysZL1C+xp5cMC+a3nggKk1Y6nqKMjNPfwRk1UgS Lorw== X-Gm-Message-State: AKS2vOyA06U3sEIWcEKyP7cvxucVlxzczCCgs9MIZjzzuQDRPoDkS0u8 rnTrsWMiXylVHd1G X-Received: by 10.223.172.15 with SMTP id v15mr4783372wrc.84.1497545112667; Thu, 15 Jun 2017 09:45:12 -0700 (PDT) Received: from snowblower (cpc4-broo7-2-0-cust35.14-2.cable.virginm.net. [82.8.215.36]) by smtp.gmail.com with ESMTPSA id o200sm558733wmg.22.2017.06.15.09.45.12 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 15 Jun 2017 09:45:12 -0700 (PDT) Date: Thu, 15 Jun 2017 17:45:09 +0100 From: Ciaran McCreesh To: gentoo-dev@lists.gentoo.org Subject: Re: [gentoo-dev] [RFC] Forced/automatic USE flag constraints (codename: ENFORCED_USE) Message-ID: <20170615174509.0260522b@snowblower> In-Reply-To: <20170615183716.0d92a5d2@gentoo.org> References: <1496071993.31087.1.camel@gentoo.org> <20170607115654.2a5da5e2@gentoo.org> <1496999960.29391.1.camel@gentoo.org> <20170609134110.418ae6ac@gentoo.org> <1497012847.25475.4.camel@gentoo.org> <20170609161619.1b72ad5b@gentoo.org> <1497025310.25475.7.camel@gentoo.org> <20170611180518.5e28ddfa@gentoo.org> <20170612110836.7b670c93@gentoo.org> <1497295036.1575.10.camel@gentoo.org> <20170613122745.455b39f7@gentoo.org> <1497392022.29918.1.camel@gentoo.org> <20170614110659.6bf4d1c2@gentoo.org> <1497443088.1223.1.camel@gentoo.org> <20170614151606.70d5d559@gentoo.org> <1497448658.1223.3.camel@gentoo.org> <20170614160939.1b15d2fa@gentoo.org> <1497542353.2933.1.camel@gentoo.org> <20170615180700.11b3ef6a@gentoo.org> <20170615171357.5a190869@snowblower> <20170615181904.25479e47@gentoo.org> <20170615172226.533e1ac9@snowblower> <20170615183010.6a249ee3@gentoo.org> <20170615173240.70e89fef@snowblower> <20170615183716.0d92a5d2@gentoo.org> X-Mailer: Claws Mail 3.13.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Archives-Salt: 5af56941-6499-4702-86f8-17291003fcc7 X-Archives-Hash: 23d59f41349463890427a9ae5b4851e7 On Thu, 15 Jun 2017 18:37:16 +0200 Alexis Ballier wrote: > > So you're saying that at the end of this, there's an ENFORCED_USE > > solver that spits out some answer that may or may not be in any way > > a sane solution to the conflict. > > > > I don't see how that's helpful to a user. > > Define sane. > The definition of the solver is made to change the least possible of > the inputs and is completely and easily predictable by the person > writing the constraint. That is something I would call sane. The problem is not just writing a resolver that spits out a valid output. The problem is writing a resolver which will never go and uninstall bash as a result of unintended combinations of inputs (which Portage used to do, but there's now a special exception for system packages, so it will only occasionally unexpectedly uninstall critical packages that aren't explicitly in system due to virtuals instead). This is *hard*. A bad suggestion to the user is worse than no suggestion at all. Unless you can safely determine that there aren't any unintended consequences of your rule, the focus needs to be on producing good error messages so the user can figure the problem out, not on producing bad solutions that will confuse things even more. -- Ciaran McCreesh