pkg does bad things after upgrade from 8.4 to 9.3

[Michael R. Wayne]

On Tue, Sep 08, 2015 at 11:06:02PM +0200, Rainer Duffner wrote:
> 
> > Am 08.09.2015 um 22:55 schrieb Michael B. Eichorn <ike at michaeleichorn.com>:
> > 
> > But you must reinstall everything. You upgraded your ABI going 8->9 so
> > everything needs rebuilt/reinstalled. See next.
> 
> Exactly.
> Or unpack the compat8x package by hand.

Explain this please?

> Or don???t delete the old libraries upon upgrading???

We never delete the old libraries. So the old binaries function.
But, the goal is to migrate to 9.X executables over time. The
motivation for this is that upgrading something almost always breaks
things and it is MUCH easier to deal with these breakages incrementally
over several days, rather than having everything broken at once.

Note that NONE of this explains why pkg would delete ANYTHING. I
can (sorta) see that upgrading bash says I have to upgrade mutt
(but, really, it should just install a new library for bash and let mutt
run on the old one) but can not think of a reason it would remove
it!