From mboxrd@z Thu Jan 1 00:00:00 1970 X-GM-THRID: 6661144938075389952 X-Received: by 2002:a17:906:9701:: with SMTP id k1mr2357218ejx.13.1552991519858; Tue, 19 Mar 2019 03:31:59 -0700 (PDT) X-BeenThere: isar-users@googlegroups.com Received: by 2002:a50:f4d8:: with SMTP id v24ls361015edm.0.gmail; Tue, 19 Mar 2019 03:31:59 -0700 (PDT) X-Google-Smtp-Source: APXvYqydTHiB4LDFT8RGPc1kFkg+tZ1zKQdHtni7iV1L2P0gzgUsaHExyCsECxPoaBaByRodE7Oz X-Received: by 2002:a50:a499:: with SMTP id w25mr2630280edb.3.1552991519178; Tue, 19 Mar 2019 03:31:59 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1552991519; cv=none; d=google.com; s=arc-20160816; b=Q/CIKmy8FdMg56EaL21SFa+b7Qhb6M68yOtOWhKCPjt5rloKpd2/3nok3FE9lWdDsd 3y27jsyv1Gy3E3wp4F53D9r9FRND7gPYvctMVr5RpqJer+MbB4jcvdYoMGjpxyfkd6KE A0sMw1tzbPNj/Ys3qEzGNUL8X9skduR/Y3O6PCfsx1hlqdrvPBtIzJ1SMClJM3InOf9v lZ75CfxzFl1Eqq7kb0f+KlcyvCbyu46GtY9r7nn5tYq3aI9n23fQUz0vC5gDA3LCqd9r A1Nnjb4QwMIwWLXBFU0aaCSR6Z+vbSUQqEGL60t/dXO6cwORFTg4IDMoJb7CyO+VmaFV RAqg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:to:subject; bh=lj6KQv3TAnQue66lIbveTA2qc2bFzRJPTD9mxH8OhWI=; b=1AcEkhJf17j0sUCx18Nj7RHePpR/yZAtj26Py30lc0Xa1oktNi03Zxzen5A2yDVHkE y6DBznwfXXQBF3zndYJrZhAOneUwG7Ds3Vo6QX2Qf+RhjI094blGJ5L3vvZ5t9xyQkdI hVLrktkA+Kp6rOj9YRVU7+Jlzc1KBO7rKsLSSIxOMiQcK0EWhmnznIhGUFLb+k9Tz4qH FiEQOzjxI9m0rDA7h3NlYY2/fxDV4co62Q8oYqR/U3Ide6luaJQlllv8jGv+aY6A9GLU o2KCyFYGlx0dw/3yone5L1rrRyX/Fsl7rWtYx7NgpZk/JtdgF+2JkwVWXw7lWYWx/vq0 e49g== ARC-Authentication-Results: i=1; gmr-mx.google.com; spf=pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.14 as permitted sender) smtp.mailfrom=jan.kiszka@siemens.com Return-Path: Received: from david.siemens.de (david.siemens.de. [192.35.17.14]) by gmr-mx.google.com with ESMTPS id r37si487565edd.2.2019.03.19.03.31.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 Mar 2019 03:31:59 -0700 (PDT) Received-SPF: pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.14 as permitted sender) client-ip=192.35.17.14; Authentication-Results: gmr-mx.google.com; spf=pass (google.com: domain of jan.kiszka@siemens.com designates 192.35.17.14 as permitted sender) smtp.mailfrom=jan.kiszka@siemens.com Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by david.siemens.de (8.15.2/8.15.2) with ESMTPS id x2JAVws9015800 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Tue, 19 Mar 2019 11:31:58 +0100 Received: from [139.22.45.157] ([139.22.45.157]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id x2JAVwG6024116 for ; Tue, 19 Mar 2019 11:31:58 +0100 Subject: Re: [PATCH] buildchroot: Allow downgrades when installing packages To: isar-users References: <88c264fd-db0f-55cc-ce5e-f19c11a45320@web.de> <20190225103935.489a466e@md1za8fc.ad001.siemens.net> <65117e48-f372-526a-08e2-35aef444c884@siemens.com> <20190225111530.36c1b655@md1za8fc.ad001.siemens.net> <20190319101001.GK16465@yssyq.m.ilbers.de> From: Jan Kiszka Message-ID: <9364cdda-1e01-389a-e586-ff0ea30e028a@siemens.com> Date: Tue, 19 Mar 2019 11:31:57 +0100 User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 In-Reply-To: <20190319101001.GK16465@yssyq.m.ilbers.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TUID: pYkZyncX3zdP On 19.03.19 11:10, Baurzhan Ismagulov wrote: > On Mon, Feb 25, 2019 at 12:08:23PM +0100, Jan Kiszka wrote: >> Removing -rcX from a version string is lexically a downgrade, logically not. >> I'm not that sure if you can compensate this. > > Debian uses tilde for that, e.g. 1.0~rc1-1+deb9u2. This is addressed in > https://www.debian.org/doc/debian-policy/ch-controlfields.html#version: > > "First the initial part of each string consisting entirely of non-digit > characters is determined. These two parts (one of which may be empty) are > compared lexically. If a difference is found it is returned. The lexical > comparison is a comparison of ASCII values modified so that all the letters > sort earlier than all the non-letters and so that a tilde sorts before > anything, even the end of a part. For example, the following parts are in > sorted order from earliest to latest: ~~, ~~a, ~, the empty part, a. [7] > > [7] One common use of ~ is for upstream pre-releases. For example, > 1.0~beta1~svn1245 sorts earlier than 1.0~beta1, which sorts earlier than > 1.0." > Good to know. We will have to educate people coming from OE about this non-intuitive deviation from how things work over there. > >> Anyway, a real downgrade is a valid development scenario as well for our >> isar-apt. > > Downgrade is supported by the packaging toolchain (dpkg / apt), but not by the > distribution (packages themselves, notably postinst, etc.). > https://www.debian.org/doc/manuals/debian-reference/ch02.en.html#_emergency_downgrading > says: > > "Downgrading is not officially supported by the Debian by design. It should > be done only as a part of emergency recovery process. Despite of this > situation, it is known to work well in many incidents. For critical systems, > you should backup all important data on the system after the recovery > operation and re-install the new system from the scratch. > > You may be lucky to downgrade from newer archive to older archive to recover > from broken system upgrade by manipulating candidate version..." > > So I'd be reluctant to do that by default. What about extracting the apt > options into a config file, where the user may add his options? I don't see that we should add a redundant, counter-intuitive option. The user already clearly expressed that packages of choice should be installed. This is what whole Isar is about: customization. Moreover, the user will get exactly that by doing a clean rebuild. So, please merge. Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux