[Mageia-dev] Proposal: Updating released versions (long post)

Fri Oct 8 22:32:03 CEST 2010

Marc Paré wrote:
+>
+> So, in terms of space used for this, if you had to install all 6,
+> would this tax the system so much and risk filling up the hardrive
+> needlessly.
+
+Not really, since the old versions would be removed when the new ones
+were installed.  The behavior I described is not part of the proposal;
+that's what happens today.
+
+>
+> It not, if a rollback were done, could all 6 as well as the new F be
+> removed and the old version restored?
+
+Yes, that's exactly what happens today.The problem is that today,
+removing them may cause tons of other packages to have to be removed
+because they require things that A-F provide.  This wasn't a problem on
+upgrade, because the removal of the old and the addition of the new was
+a single urpmi "transaction" (I put this in quotes because urpmi uses
+"transaction" to mean something other than what I mean here), and urpmi
+"knew" that the new versions supplied all the things that vanished when
+the old versions were removed.  Today, rollbacks have to be done
+manually - remove new, then install old.  Urpmi doesn't know at the time
+of the removal that you're going to turn around and install the old
+versions next.  It only sees that all the things that both the old and
+new versions supply are about to disappear from your system, so it tells
+you that you have to remove any other package which requires those things.
+>
+> If this is possible, would this have an impact on devs preparing
+> Backport versions with rollbacks?
+
+RPM dependencies aren't a problem.  Urpmi/urpme know all about them. 
+The only packaging changes would be for situations like that where a new
+version of an application has changed a format of one of its files in
+your home directory and the new version automatically converts the old
+version of the file to the new format.  In that case, the package would
+need install scriptlets that copied the old version somewhere so that it
+could be restored at uninstall time, otherwise the old version of the
+software won't be able to use the new file format.
+
+The biggest chunk of development involved in the proposal is to make
+urpmi do a rollback as a single operation, just as it does an upgrade. 
+This already exists, in a way; there is a facility called urpmi.recover
+that does this type of thing.  Bit it's not really considered
+mainstream, and I don't think it's been supported for a while.
+
+