Re: How to detect an upgrade from an older version of a package

[Patrick Schoenfeld <schoenfeld@in-medias-res.com>]

Hi,

On Mon, Jul 14, 2008 at 04:05:05PM +0300, Eugene V. Lyubimkin wrote:
> > I know many "hacks" to know that I'm upgrading (like doing dpkg -l,
> > etc.), but what is the correct/policy way to know from what version my
> > package is upgrading, so my postinst can run smoothly?
> Policy 6.6.3 says
> 
> "If the package is being upgraded, call:
> 
>           new-preinst upgrade old-version
> "
> Is it what you are seeking?
> 

Additional (might be more to his interest, because he talked about his
postinst) it says:

"
postinst configure most-recently-configured-version
"

If a package is upgraded the most-recently-configured-version is usually
identical to old-version. It isn't if the configuration of the package
already took place but the installation hasn't finished (half-installed
state). That is as far as I understand it. Anyways using $2 as
oldversion worked for me in every case so far.

Regards,
Patrick