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

Package:
apt
Source:
apt
Description:
commandline package manager
Submitter:
Daniel Schepler
Date:
2017-11-19 18:06:03 UTC
Severity:
important
#882151#5
Date:
2017-11-19 17:03:12 UTC
From:
To:
Package: apt
Version: 1.6~alpha5
Severity: important
X-Debbugs-CC: pkg-gnome-maintainers@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@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.
#882151#10
Date:
2017-11-19 17:24:29 UTC
From:
To:
What architecture are you using? Are you running kfreebsd or hurd by any chance?
Using reportbug would give us that information fwiw...

Emilio
#882151#15
Date:
2017-11-19 17:28:42 UTC
From:
To:
This was on amd64 (using a just updated pbuilder chroot of sid, so the
host system details reported by reportbug wouldn't necessarily be
completely relevant).
#882151#20
Date:
2017-11-19 17:37:49 UTC
From:
To:
### Dependency resolution

APT works in its internal resolver in two stages: First all packages are visited
and marked for installation, keep back or removal. Option `Debug::pkgDepCache::Marker`
shows this. This also decides which packages are to be installed to satisfy dependencies,
which can be seen by `Debug::pkgDepCache::AutoInstall`. After this is done, we might
be in a situation in which two packages want to be installed, but only on of them can be.
It is the job of the pkgProblemResolver to decide which of two packages 'wins' and can
therefore decide what has to happen. You can see the contenders as well as their fight and
the resulting resolution with `Debug::pkgProblemResolver`.


(README.md)

Thanks!
#882151#25
Date:
2017-11-19 18:02:05 UTC
From:
To:
OK, attaching the results of "apt -o Debug::pkgDepCache::Marker=1 -o
Debug::pkgDepCache::AutoInstall=1 -o Debug::pkgProblemResolver=1
install libgtk-3-dev".