GDM crashes when Sugar session is selected

*** START SRU INFO ***
This package causes GDM to crash as-is. The fix is to add a comment to the .desktop file. This is not fixed in Maverick, but the fix has been well-tested and will be included in the next Debian version of the package. slangasek on IRC said he didn't see a problem with uploading this without fixing it in Maverick first.

** TEST CASE **
Install sugar-0.88. Switch to GDM. Select a user, and select "Sugar" as the session.

OLD BEHAVIOR: GDM should crash, disappearing from the screen.
NEW BEHAVIOR: The option is selected.

*** END SRU INFO ***
I installed Sugar, and the session is properly listed as an option from GDM, but as soon as I select that session with the combo box GDM immediately crashes. This does not happen for any other sessions and occurs all the time for me.

I poked through the system log and the following stood out:

Mar 19 17:30:45 dylan-netbook gdm-session-worker[1439]: GLib-GObject-CRITICAL: g_value_get_boolean: assertion `G_VALUE_HOLDS_BOOLEAN (value)' failed
Mar 19 17:30:49 dylan-netbook gdm-simple-slave[933]: CRITICAL: Cannot read specified session file: sugar.desktop
Mar 19 17:30:49 dylan-netbook gdm-binary[767]: WARNING: GdmDisplay: display lasted 0.112974 seconds
Mar 19 17:30:49 dylan-netbook gdm-simple-greeter[1477]: WARNING: error opening connection: Failed to connect to socket /tmp/gdm-greeter-CveyZvQE: Connection refused

The fact that GDM is crashing is being filed as a separate bug.

Here is % cat /usr/share/xsessions/sugar.desktop
[Desktop Entry]
Encoding=UTF-8
Name=Sugar
GenericName=Sugar
Exec=sugar
Type=Application

ProblemType: Bug
Architecture: i386
Date: Fri Mar 19 17:41:36 2010
DistroRelease: Ubuntu 10.04
NonfreeKernelModules: wl
Package: sugar-session-0.88 0.87.2-1
PackageArchitecture: all
ProcEnviron:
 LANG=en_CA.utf8
 SHELL=/bin/zsh
ProcVersionSignature: Ubuntu 2.6.32-16.25-generic
SourcePackage: sugar-0.88
Uname: Linux 2.6.32-16-generic i686