unity --reset fails if Ubuntu Unity Plugin disabled in ccsm

[Colin Law]

If the Ubuntu Unity Plugin has been disabled in Compiz Config Settings Manager then unity --reset hangs and does not fix the problem (which is that the launcher and panel do not exist).
The man page for unity says
       --reset
              This option allows the user to reset profile parameters in compiz and restart the
              Unity shell with default settings.
Which does suggest that it should cope with this situation.

Just for the record bug #777024 allows one to get into this situation accidentally

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.22.0-0ubuntu3
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu3
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,compiztoolbox,gnomecompat,resize,grid,place,regex,imgpng,mousepoll,vpswitch,move,snap,wall,session,animation,workarounds,expo,ezoom,staticswitcher,fade,scale,unityshell]
Date: Tue Oct 25 20:40:57 2011
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 PATH=(custom, user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: Upgraded to oneiric on 2011-10-14 (11 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Rom Raptor (romraptor)]

i can confirm this bug also

[Rom Raptor (romraptor)]

since everything disappears from the screen and a beginner wouldn't be able to fix this I think
"importance: Undecided → Low" is not enough

[Andrew Starr-Bochicchio (andrewsomething)]

Can someone provide some steps to reproduce this problem?

I thought I'd try my hand at fixing it, but I 'can reproduce. I triggered unity being disabled like the original reporter by reproducing bug #777024, but for me "unity --reset" works as expected and re-enables the unityshell plugin.

$ unity --version
unity 4.28.0
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.10
Release: 11.10
Codename: oneiric

[Omer Akram (om26er)]

Now in Ubuntu 12.04 the unity plugin cannot be disabled from CCSM so this won't apply anymore.