LightDM doesn't take full ownership of /var/lib/lightdm which can prevent lightdm from starting

[Jeremy Bícha]

1. Install lightdm
2. Remove lightdm
3. Install some random package that adds a new system user
4. Install unity-greeter which pulls in lightdm
5. Set lightdm as default and either reboot or kill any other dm's and sudo service lightdm start

What should happen
================
You get the pretty Unity greeter

What does happen
===============
You get the X failed to start box.

During the install in step 4, I got this output:

Setting up lightdm (1.3.3-0ubuntu4) ...
Adding group `lightdm' (GID 131) ...
Done.
Warning: The home dir /var/lib/lightdm you specified already exists.
Adding system user `lightdm' (UID 119) ...
Adding new user `lightdm' (UID 119) with group `lightdm' ...
The home directory `/var/lib/lightdm' already exists. Not copying from `/etc/skel'.
adduser: Warning: The home directory `/var/lib/lightdm' does not belong to the user you are currently creating.
usermod: no changes
usermod: no changes
usermod: no changes

I verified that /var/lib/lightdm was owned by lightdm:lightdm. However, there are a bunch of left-over dot files and directories inside /var/lib/lightdm that are owned by some other random system user.

Proposed fix
==========
This in debian/lightdm.postinst should be recursive:

if [ -d /var/lib/lightdm ]; then
  chown lightdm:lightdm /var/lib/lightdm
  chmod 0750 /var/lib/lightdm
fi

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: lightdm 1.3.3-0ubuntu4
ProcVersionSignature: Ubuntu 3.5.0-15.22-generic 3.5.4
Uname: Linux 3.5.0-15-generic x86_64
ApportVersion: 2.5.2-0ubuntu4
Architecture: amd64
Date: Mon Sep 24 16:58:04 2012
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Robert Ancell (robert-ancell)]

Was fixed in 1.4.0-0ubuntu3