At the moment pacman has the well-known behavior of creating either .pacnew and/or .pacsave files during upgrades of configuration files that need to be manually reviewed after an upgrade.

It would be nice to have a configurable option in pacman.conf to enable interactive management of these files during upgrade.

Debian/apt handle this with the following output:

Configuration file `/etc/apache2/mods-available/php5.conf'
==> Deleted (by you or by a script) since installation.
==> Package distributor has shipped an updated version.
What would you like to do about it ? Your options are:
Y or I : install the package maintainer's version
N or O : keep your currently-installed version
D : show the differences between the versions
Z : start a shell to examine the situation
The default action is to keep your current version.
*** php5.conf (Y/I/N/O/D/Z) [default=N] ?