preventing known-damaging third-party to fedora/epel package upgrade?

[Peter Jones]

On 07/12/2012 11:20 AM, Tom Callaway wrote:
> On 07/12/2012 11:01 AM, Paul Wouters wrote:
>> I would like to prevent this from happening. But since this only happens
>> when  upgrading from a third-party 1.3 (which we don't ship) to a 1.4,
>> even if I used triggers to work around the config file issue, the users
>> would end up with a broken database setup anyway. I could address that
>> with an auto-migration script, but then any accidental upgrade would be
>> even harder for those people who wanted to remain on 1.3. to downgrade back.
>
> Make backup copies of the config file and database before you migrate,
> and print a notice in the %triggerun explaining the situation and these
> new files?

So, this makes me wonder.  Is there a good reason rpm doesn't check the new
package and the old package for having the same file during an upgrade, and
simply use the flags on the incoming package if they're both present?

Is it just that we've never done it that way?

-- 
         Peter