I just performed an aptitude upgrade. This failed during the Setup stage of Hudson:

Setting up hudson (1.349) ...
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dijit': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dojo': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dojox': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/DojoDemo/dojodemo/public/dojo': No such file or directory
dpkg: error processing hudson (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
hudson
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
Setting up hudson (1.349) ...
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dijit': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dojo': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/RefGui/js/dojox': No such file or directory
chown: cannot dereference `/var/lib/hudson/workspace/trunk/ref-web-gui/DojoDemo/dojodemo/public/dojo': No such file or directory
dpkg: error processing hudson (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
hudson

the files which are causing problems are symbolic links which point to none existent files. Since this is inside a workspace, you can expect wired and wonderful things, like broken symbolic links. So i would not expect this to cause a failure during the package upgrade.