unmet dependencies in juju-deployer : Depends: python3-juju-deployer but it is not going to be installed

[Ryan Beisner]

Use of the MOJO maintainers PPA has provided a broken juju-deployer package, interrupting OpenStack Charm CI.

jenkins@juju-osci1-machine-16:~$ juju-deployer
The program 'juju-deployer' is currently not installed. To run 'juju-deployer' please ask your administrator to install the package 'juju-deployer'

.

jenkins@juju-osci1-machine-16:~$ apt-cache policy juju-deployer
juju-deployer:
  Installed: 0.9.2~bzr203~60~ubuntu16.04.1
  Candidate: 0.9.2~bzr203~60~ubuntu16.04.1
  Version table:
 *** 0.9.2~bzr203~60~ubuntu16.04.1 500
        500 http://ppa.launchpad.net/mojo-maintainers/ppa/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status
     0.6.4-0ubuntu1 500
        500 http://nova.clouds.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
     0.6.4~bzr168~49~ubuntu16.04.1 500
        500 http://ppa.launchpad.net/juju/stable/ubuntu xenial/main amd64 Packages

.

jenkins@juju-osci1-machine-16:~$ sudo apt-get install --reinstall juju-deployer
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 juju-deployer : Depends: python3-juju-deployer but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).
jenkins@juju-osci1-machine-16:~$

[Ryan Beisner (1chb1n)]

Although manually resolving dependencies is a work-around, if there are dependency declaration issues in the packaging, future package upgrades will be predictably problematic.

[William Grant (wgrant)]

I can't reproduce the dependency issue. If you still can, what does "sudo apt-get install juju-deployer python3-juju-deployer" say? It should explain why it won't install both.

[Ryan Beisner (1chb1n)]

I believe the issue arises when a user already has/had juju-deployer from ppa:juju/stable, then adds the mojo ppa and upgrades the packages.

[Ryan Beisner (1chb1n)]

Also: comment #2 describes the workaround accurately. A user is now apparently expected to also specify they want the py3 variant package along with the juju-deployer package. We've done that in OSCI and have no further issues.

[Xav Paice (xavpaice)]

Note that with juju-deployer 0.10 (bzr 212 at least) there's files conflicting with python3-juju-deployer in the juju-deployer package itself.