Various qt 5.9 packages are being uploaded to the unstable archives now, but
as there are quite a few of them, they not all land in unstable at the same
time. That's a consequence of running *unstable*, these things happen.
Your best course of action (imo) is adding testing to your sources and
downgrade the 5.9 packages to the 5.7 ones ... and probably prefer testing
(over unstable) and maybe also stick with testing instead of unstable.
While, I do hear that (usual excuse for breaking unstable, and telling
users to shut up), I nevertheless would like to say that qt 5.9.x has
been in experimental for over a month (beginning of July at least if
memory serves), with kde 5.28 been added later on also to experimental
and that very same dependency problem had existed identically in
experimental for as long and nobody did fix it, and then we rediscover
it in unstable with a much wider audience. I would have expected this
kind of transition being part of experimental before moving to unstable
as it has been in the past.
Seamlessly, kde 5.37 is currently landing in experimental but is also
currently uninstallable for the very same root reason.
-- eric
