Comment 9 for bug 717397

It doesn't seem that this package handles the state where squid is in the stop/waiting state prior to upgrade. The previous restart style stanzas are encapsulated in checking current status if statements.

Setting up squid (2.7.STABLE7-1ubuntu12.2) ...
restart: Job failed to restart
dpkg: error processing squid (--configure):
 subprocess installed post-installation script returned error exit status 1
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
Setting up squid (2.7.STABLE7-1ubuntu12.2) ...

Aptitude did successfully recover from this situation, currently unsure how apt-get would. Although this has an edge case, it's a better situation than leaving bug 725635 out in the wild.