re: Sorting out mail-transport-agent mess
2) Introduce a default-mta package (currently) depending on exim4. All
packages requiring a MTA should depend on default-mta | mail-transport-agent.
This will have the extra advantage that we (and others like CDDs and derived
distros) easily could swap default MTA.
What concerns me about this approach is that it could easilly end up with
dist-upgrades swapping out users mail systems without warning. I would consider
such behaviour unacceptable as it could easilly cause mail loss if the user has
a customised configuration.
It seems to me that the ideal soloution would be to fix apt/the repositry system
so that the defaults for a virtual package can be explicitly designed.
Failing that how about a default-mta virtual package that is provided by *exactly
one* real package. That way it is easy to change the default but upgrades should
stay with the version that they have. Under that system changing the default MTA
would require changes to two packages which seems manageable to me.