The patch works around the issue in apt, but isn't the underlying cause the fact that /etc/apt/apt.conf.d/50unattended-upgrades was a confffile in ~0.82.1ubuntu2.3, and is no longer a conffile in ~0.90ubuntu0.3, yet the typical pattern for obsoleting a conffile wasn't performed? So even an unchanged 50unattended-upgrades is seen as a conflict by the ucf code, and thuse the .ufc-dist file is created, and the user is asked to resolve a "conflict" in a file that wasn't changed.
The patch works around the issue in apt, but isn't the underlying cause the fact that /etc/apt/ apt.conf. d/50unattended- upgrades was a confffile in ~0.82.1ubuntu2.3, and is no longer a conffile in ~0.90ubuntu0.3, yet the typical pattern for obsoleting a conffile wasn't performed? So even an unchanged 50unattended- upgrades is seen as a conflict by the ucf code, and thuse the .ufc-dist file is created, and the user is asked to resolve a "conflict" in a file that wasn't changed.