update to system fails with Exception value: 'NoneType' object has no attribute 'os_version'

While I was trying to update a system/profile definition, I got hit by the backtrace below. Given the last line in the backtrace suggests this is an error in a 'distro' instance, I went and edited the disto affected: same error.

I then tried _other_ distros, and they also failed (but I did not try all). This was working as of 2.1.0+git20110602-0ubuntu26, ergo I suspect a regression.

Cobbler version: 2.1.0+git20110602-0ubuntu26.1Ubuntu version: Oneiric 11.10

Wed Feb 29 00:27:10 2012 - DEBUG | get_item; ['profile', 'lucid-i386']
Wed Feb 29 00:27:10 2012 - DEBUG | authorize; ['cobbler', 'save_profile', <cobbler.item_profile.Profile instance at 0x232dbd8>, None, True]Wed Feb 29 00:27:10 2012 - DEBUG | REMOTE cobbler authorization result: True; user(?)Wed Feb 29 00:27:10 2012 - INFO | add_item(profile); ['lucid-i386']
Wed Feb 29 00:27:10 2012 - DEBUG | get_items; ['profile']
Wed Feb 29 00:27:10 2012 - INFO | generating: /var/lib/tftpboot/pxelinux.cfg/01-bc-30-5b-e2-a1-80
Wed Feb 29 00:27:10 2012 - INFO | generating: /var/lib/tftpboot/grub/01-BC-30-5B-E2-A1-80
Wed Feb 29 00:27:10 2012 - INFO | generating: /var/lib/tftpboot/pxelinux.cfg/01-bc-30-5b-e2-a1-7a
Wed Feb 29 00:27:10 2012 - INFO | generating: /var/lib/tftpboot/grub/01-BC-30-5B-E2-A1-7A
Wed Feb 29 00:27:10 2012 - INFO | Exception occured: <type 'exceptions.AttributeError'>
Wed Feb 29 00:27:10 2012 - INFO | Exception value: 'NoneType' object has no attribute 'os_version'
Wed Feb 29 00:27:10 2012 - INFO | Exception Info:
  File "/usr/lib/python2.7/dist-packages/cobbler/remote.py", line 1928, in _dispatch
    return method_handle(*params)
   File "/usr/lib/python2.7/dist-packages/cobbler/remote.py", line 933, in save_item
    rc = self.api.add_item(what,obj)
   File "/usr/lib/python2.7/dist-packages/cobbler/api.py", line 455, in add_item
    return self.get_items(what).add(ref,check_for_duplicate_names=check_for_duplicate_names,save=save,logger=logger)
   File "/usr/lib/python2.7/dist-packages/cobbler/collection.py", line 314, in add
    self.lite_sync.add_single_profile(ref.name)
   File "/usr/lib/python2.7/dist-packages/cobbler/action_litesync.py", line 119, in add_single_profile
    self.sync.pxegen.make_pxe_menu()
   File "/usr/lib/python2.7/dist-packages/cobbler/pxegen.py", line 312, in make_pxe_menu
    self.make_actual_pxe_menu()
   File "/usr/lib/python2.7/dist-packages/cobbler/pxegen.py", line 406, in make_actual_pxe_menu
    profile=None, distro=None, arch=image.arch, image=image)
   File "/usr/lib/python2.7/dist-packages/cobbler/pxegen.py", line 611, in write_pxe_file
    elif distro.os_version.startswith("esxi"):

ProblemType: BugDistroRelease: Ubuntu 11.10
Package: cobbler 2.1.0+git20110602-0ubuntu26.1
ProcVersionSignature: Ubuntu 3.0.0-12.20-server 3.0.4
Uname: Linux 3.0.0-12-server x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Wed Feb 29 00:49:24 2012InstallationMedia: Ubuntu-Server 11.04 "Natty Narwhal" - Release amd64 (20110426)
PackageArchitecture: allSourcePackage: cobblerUpgradeStatus: Upgraded to oneiric on 2011-11-16 (104 days ago)

[SRU REQUEST] - ONEIRIC

[Impact]
If am image is found, during PXE setup, the process may abort with the backtrace above. When this happens, no updates or usage of the affected profiles/systems is possible anymore, effectively disabling Cobbler.

[Development Fix]
A fix has been written by Scott Moser, and uploaded to precise; an upstream merge has been requested (https://github.com/cobbler/cobbler/pull/94) and approved/applied

[Stable Fix]A fix to Oneiric has been proposed; this fix is slightly different from upstream due to changes in the code from 2.1 to 2.2.2 and GIT. A package has been built on a PPA (https://launchpad.net/~smoser/+archive/ppa) to field-test it; this same fix has already been deployed on personal package build by C de-Avillez.

[Test Case]
-- BEFORE applying the fix:
1. You MUST have images on your Cobbler install, and MUST try to update a profile/system with images.
2. Edit the profile/system;
3. Click on the SAVE button at the bottom.

FAILS -- an error is shown, and the /var/log/cobbler/cobbler.log shows a backtrace as above;

-- AFTER applying the fixed package, and AFTER restarting Cobbler:
Repeat steps (1)-(3) above.
SUCCEEDS -- the save completes with no errors.

[Regression Potential]
Patch is isolated, straightforward, and affects only the code path in the backtrace.

[Original Report]
This is it. Additionally, there is https://github.com/cobbler/cobbler/issues/16 upstream.