Comment 31 for bug 362691

Attached is my current work-in-progress patch for Karmic, that also closes bug #286450 and bug #346003, but it's not ready to be uploaded yet.

Both the attached patch and the patch currently in jaunty-proposed will break on further upgrades, because for some reason the prerm for python-xen-3.3 is being run before the prerm for xen-utils-3.3. I'm not sure why this is - xen-utils-3.3 depends on python-xen-3.3, but because of what's happening now, the Python module symlinks are being removed by pycentral before xen-utils-3.3's prerm can stop xend, which results in the prerm failing, leaving the package broken:

> Reading package lists... Done
> Building dependency tree
> Reading state information... Done
> Reading extended state information
> Initializing package states... Done
> The following packages will be upgraded:
> libxen3 python-xen-3.3 xen-docs-3.3 xen-hypervisor-3.3 xen-utils-3.3
> 5 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
> Need to get 1945kB of archives. After unpacking 0B will be used.
> Do you want to continue? [Y/n/?]
> Writing extended state information... Done
> Get:1 http://ppa.launchpad.net karmic/main libxen3 3.3.0-1ubuntu10~broder8 [151kB]
> Get:2 http://ppa.launchpad.net karmic/main python-xen-3.3 3.3.0-1ubuntu10~broder8 [378kB]
> Get:3 http://ppa.launchpad.net karmic/main xen-docs-3.3 3.3.0-1ubuntu10~broder8 [13.5kB]
> Get:4 http://ppa.launchpad.net karmic/main xen-hypervisor-3.3 3.3.0-1ubuntu10~broder8 [514kB]
> Get:5 http://ppa.launchpad.net karmic/main xen-utils-3.3 3.3.0-1ubuntu10~broder8 [888kB]
> Fetched 1945kB in 4s (407kB/s)
> (Reading database ... 31548 files and directories currently installed.)
> Preparing to replace libxen3 3.3.0-1ubuntu10~broder7 (using .../libxen3_3.3.0-1ubuntu10~broder8_amd64.deb) ...
> Unpacking replacement libxen3 ...
> Preparing to replace python-xen-3.3 3.3.0-1ubuntu10~broder7 (using .../python-xen-3.3_3.3.0-1ubuntu10~broder8_amd64.deb) ...
> Unpacking replacement python-xen-3.3 ...
> Preparing to replace xen-docs-3.3 3.3.0-1ubuntu10~broder7 (using .../xen-docs-3.3_3.3.0-1ubuntu10~broder8_amd64.deb) ...
> Unpacking replacement xen-docs-3.3 ...
> Preparing to replace xen-hypervisor-3.3 3.3.0-1ubuntu10~broder7 (using .../xen-hypervisor-3.3_3.3.0-1ubuntu10~broder8_amd64.deb) ...
> Unpacking replacement xen-hypervisor-3.3 ...
> Preparing to replace xen-utils-3.3 3.3.0-1ubuntu10~broder7 (using .../xen-utils-3.3_3.3.0-1ubuntu10~broder8_amd64.deb) ...
> Cannot find Xen Python modules.
> invoke-rc.d: initscript xend, action "stop" failed.
> dpkg: warning - old pre-removal script returned error exit status 1
> dpkg - trying script from the new package instead ...
> Cannot find Xen Python modules.
> invoke-rc.d: initscript xend, action "stop" failed.

I'm still working to figure out why the prerms are getting run in the wrong order; I just wanted to keep everyone following this bug updated on progress.