[Rpm-maint] upgrade process

[Michael Schroeder]

On Fri, Mar 13, 2009 at 03:57:22PM +0000, Tom Brown wrote:
> >Not really. The order is:
> >
> >    prein new
> >    install files from new
> >    postin new
> >    preun old
> >    delete files from old that are not shared
> >    postun old
> >
> >  
> 
> so i am loosing the symlink as it gets removed by the postun in the old 
> package - i guess i need to work on the install/upgrade/erase syntax in 
> there but i am struggling to fins an example i fully understand!!

There are two ways to detect if it's an update or not:

1) check $1 in the postun script, it contains the number of left
   packages with the same name. Thus, if it's zero, it's a delete,
   otherwise it's an update
2) check for the existance of some crucial file. If it's no longer
   there, it's a delete.

Method 2) has the advantage that it also works with package renames.

The real problem you have is that there's no way to fix the bugs in
scriptlets of the installed packages.

(off-topic:

I think we should thus extend rpm to make things easier. How about
adding support for %update scriptlets? The order would be

    preup new
    install files from new
    delete files from old that are not shared
    postup new

No preun/postun would be run in -U mode if the new package has a preup
or postup scriptlet. rpm should also tell the up scripts wich
packages in which versions were obsoleted. Maybe as a list of
HDRNUMs so that the scriplets can do a --querybynumber.

off-topic-end)

Cheers,
  Michael.

-- 
Michael Schroeder                                   mls at suse.de
SUSE LINUX Products GmbH, GF Markus Rex, HRB 16746 AG Nuernberg
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