Bug#882151: apt is having trouble resolving dependencies of libgtk-3-dev in sid

[Daniel Schepler]

Package: apt
Version: 1.6~alpha5
Severity: important
X-Debbugs-CC: pkg-gnome-maintainers at lists.alioth.debian.org
Affects: libgtk-3-dev

Recently, in pbuilder builds on my machine, apt has been having
trouble figuring out how to install libgtk-3-dev.  Debugging within a
"pbuilder login" session shows:

root at frobozz:/# apt install libgtk-3-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libgtk-3-dev : Depends: gir1.2-gtk-3.0 (= 3.22.26-1) but it is not
going to be installed
E: Unable to correct problems, you have held broken packages.

The strange thing is, if I try to dig into what the problem is with
"apt install libgtk-3-dev gir1.2-gtk-3.0", then the installation is
successful.  So the package is actually installable, it's just that
for some reason apt is having difficulties figuring out the
installation set.
-- 
Daniel Schepler