Comment 5 for bug 209515

Jelmer's post from that thread:

> > While PPA is building packages there still might be a (short) period of
> > time, where the packages are inconsistent. It would be a useful
> > launchpad feature to hold back packages until the desired dependencies
> > are fulfilled. But even for now it would be better to have an unusable
> > repository for five or ten minutes than for a few days.
> That's really just a workaround for a problem caused by PPA.
>
> APT can deal with multiple versions of packages just fine, but PPA
> removes older versions. For example, if the latest version of bzrtools
> available only works with bzr 1.2 but the latest bzr available was 1.3,
> apt would install bzr 1.2 and warn you it's not upgrading bzr.