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

andré andr55 at laposte.net
Sat Oct 9 05:45:16 CEST 2010

Frank Griffin a écrit :
> Marc Paré wrote:
>> Thanks. So this thread is to see if there were a possibility to
>> programme a more efficient roll-back option so that it would be more
>> "aware" of the previous "dependencies" needs for the previous version.
>> Having "double dependencies" is not so much of a problem, it is the
>> rollback to a previous version where the dependency confusion may
>> occur, and, ONLY, if an upgraded type of "dependency" thread had been
>> installed. (Sorry I may have used the wrong terms in the last sentence).
> Well, sort of.  It's not an issue of efficiency, but of convenience and
> just making it possible to do without resorting to manual use of the rpm
> command.
> The rpm command "knows" that a new version replacing the old version
> supplies the same things that the old one did, so it will quietly allow
> the upgrade.  It will also do what we need, i.e. go the other way and
> replace a newer version with an older one if you use the --oldpackage
> keyword.  We just need urpmi to support its use

One thing that could facilitate this process, if the computer has a lot 
of free disk space, is to rename the files being removed (copying the 
configuration files), instead of erasing them.  Although they will 
probably have to be erased eventually, since no computer has unlimited 
disk space.  Keeping them long enough that a roll-back is no longer 
probable could be workable.
Then a roll-back could be done very quickly, since the files are already 
on disk, and presumably reliably.  Of course, if new data has been 
entered, and the format has been changed, this could be problematic.
Note that configuration files that have been changed from the 
installation default are often already saved.  (Generally ".old" is 
appended to the configuration file name, sometimes ".new" to the new 
configuration file.)
This of course adds the maintenance task of removing the old files at 
some point - it could be done automatically according to some criteria, 
or the user could have to do it manually, perhaps after being prompted 
about it.

(This rollback capability occurs with Microsoft products.  The saved 
files are only removed manually, on user initiative, which partly 
explains the bloated size of a Microsoft installation over time.)

If renaming-instead-of-deleting is implemented, perhaps a "do not keep 
old program files (useful if limited disk space)" checkbox option would 
be useful for computers with less free disk space.
Of course how much disk space is usable to save old programs on a 
computer depends on the disk space usage for other purposes over time.

my 2 cents :)

- André (andre999)

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