MTA in ubuntu deskop

[LaMont Jones]

This was kicked around at the tech board meeting, but I wanted to get a
little more widespread discussion before I just did it...

Feedback has shown that the choice of MTA is rather religious (duh) ,and
that users expect that an MTA, if present, will actually work for them.
Sadly, the postfix in the standard install fails this expectation, since
it's installed to do only local mail delivery, per base-install policy.

At a high level, the plan is thus:
1) Move postfix to ship seed, and replace it with nothing.  That's
   right, no /usr/sbin/sendmail on the desktop until the user installs it.
   THIS WILL HAPPEN THIS WEEK. (before feature freeze...)
2) Change anacron, at, and cron to abuse the interactive upgrade hooks
   (http://www.ubuntu.com/wiki/InteractiveUpgradeHooks) to deliver
   output to the user if sendmail isn't there or fails to execute.
   QUESTION: does this want a global config file to tell these fine
   programs to use the hooks unconditionally, or should they just
   automatically switch to using the MTA when it arrives?
   This will happen post-feature-freeze.  If this runs into challenges,
   modify the programs to warn the user that they won't get output from
   their command unless they install a mail transport agent.
3) The other packages are seed changes only, and will be done as part of
   #1, before feature freeze.

There was some discussion of delivering a minimalist mail delivery agent
as part of ubuntu-base, but that still leaves us with issue #2 above,
and concensus seemed to be that we would not do it.

At a lower level, here are the packages, and what changes in them:

The following packages Provide: mail-transport-agent:
  postfix	Move to ship seed, restore the questions needed for full
  		configuration at install time.  Change all of the other
		packages to
		  Depend/Recommend: postfix | mail-transport-agent
		rather than exim4 | mail-transport-agent

The following packages Recommend: mail-transport-agent:
  cron		If /usr/sbin/sendmail isn't there, then cron generates an
		error and exits, discarding the job output.
    		Crontab should issue a warning when installing a crontab
		(either new or editing) if /usr/sbin/sendmail is not
		present.
  procmail 	Move to ship seed.

The following packages Depend: mail-transport-agent:

  anacron	Behavior is the same as cron, same changes
  at		Behavior is the same as cron, same changes
  lsb		Move to ship seed, document that one needs to install
		lsb to have an LSB compliant system.
  mailx		Move to ship seed
  mutt		Move to ship seed

Lastly, the following package Depends: mail-transport-agent in error (it
doesn't actually use it anymore):
  popularity-contest	fix dependency

Thoughts?
LaMont "that postfix guy" Jones