From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikita Karetnikov Subject: Re: Rollback problems Date: Thu, 24 Jan 2013 21:44:39 -0500 Message-ID: <87622mhthi.fsf@karetnikov.org> References: <201301232148.46744.andreas@enge.fr> <87mwvzsdzt.fsf@gnu.org> <201301240017.55013.andreas@enge.fr> <87mwvystku.fsf@gnu.org> <87bocel2vo.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Return-path: Received: from eggs.gnu.org ([208.118.235.92]:48929) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TyZHT-0002XX-F4 for bug-guix@gnu.org; Thu, 24 Jan 2013 21:44:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TyZH9-000886-QL for bug-guix@gnu.org; Thu, 24 Jan 2013 21:44:39 -0500 In-Reply-To: <87bocel2vo.fsf@gnu.org> ("Ludovic =?utf-8?Q?Court=C3=A8s=22'?= =?utf-8?Q?s?= message of "(unknown date)") List-Id: Bug reports for GNU Guix List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org Sender: bug-guix-bounces+gcggb-bug-guix=m.gmane.org@gnu.org To: Ludovic =?utf-8?Q?Court=C3=A8s?= Cc: bug-guix@gnu.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable > 3. More generally, should the history of generations be linear, or > should it be a DAG like Git commits? If the latter is the case, then we can probably use a simple tree. Here is a related link: [1]. > Regarding (3), it seems that a linear history not only simplifies the > implementation, but also the user interface, while covering most > practical use cases. I agree. > Let me illustrate. Suppose these generations: > A ------> B ------> C > When doing a roll-back from C, one should obviously get back at B. At > that point, C would still be available. Keeping it around means that > users can easily switch back to C if B turned out to be less appropriate > (this answers questions (1) and (2)). > Once at B, installing or removing packages would delete C, thus allowing > its generation number to be reused, and create a new generation C=E2=80= =99 with > the same generation number as C: > A ------> B ------> C=E2=80=99 > At this point, switching back to C is no longer possible. I like the idea. Nikita [1] http://learnyouahaskell.com/zippers#a-very-simple-file-system --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAEBAgAGBQJRAfF+AAoJEM+IQzI9IQ38xlcQAJ7brI/i4GJV1WmK4sbvRKZv MZP9CTB1HZxDDn3FqcXexoLO/P1Hjb5zI73bCw3vHdD6bb7yliqGENVU/AcSM0Kr NzFYix/IspiiYTbyRvqb/uSyKdb09mb25dyIEQPDJ4ryLEypOVMQaE1nzNJDmCmS LgDs2jAdsApeG3uxN5/R+R5Fjm8QsqB68Levj5+xfTNPuieznAIfSVDmRYuiAJhI SByShkd+u/nmhWAev6D29lu1xI9DdRTTZoDdhWGsONis7qLsHiRRRY+9navLG7fh F3ttP7Gy85g4q/LmtDidTzXi+5e/HVkR92JfHjUa+fnd3DU7UOM1blFxQHWnKKj7 CWGFcS1ImkpdBMzoMY6KT0or7NP4Y7vkHO+e/w6jVY6WU5rYfdpbFRp2RKGEkHdT TbT3h1PUlVBtR6jYhXTfOV6MqG0OzIDNN26zwEYdd45C0SwQFZoqkf5zLiaimUZB lN5L+LJuu6HJHHOHIlAvfHe8Qmxh5uxSmU0N7TMlZG2KgOP2blfU2hFODtyqIH8n shiAuJOzTYANVRrroE7g5xXOl26Boy34alqAOjGMlO/e4WYZeupBf+3XgrW15PR5 iW4P/Xu30cuebZzq8+JQec+u5Ym4taQezTEcL+H1Gxz/tpV1RLikjmCPbtIRpplK w2RPApWbGykfDkn1OXEv =s3lV -----END PGP SIGNATURE----- --=-=-=--