Old-style virtuals blocking feature needed for virtual/mta
* Ciaran McCreesh <firstname.lastname@example.org>:
> Is there anything in particular holding back replacing most or all of
> the remaining old-style virtuals with new 'package' virtuals?
> There's still that stupid !virtual/blah thing to deal with. Old style
> virtual providers are allowed to block their own virtual to mean "there
> must not be any other provider of this installed" (although it's not
> clear what that means if anything other than a simple !virtual/pkg is
> used). Anything doing that would now have to explicitly list its own
> blocks. Arguably, this is a good thing, since you'd have to say exactly
> what you do and don't work with.
This is a problem for virtual/mta.
As long as we have to block all other mailers with the sendmail
compatibility interface to avoid collisions, adding explicit blockers
for mailers in all repositories is unlikely to work well.
The former mailwrapper/mailer-config tools solved this problem but they
were too slow. Once we have a better alternatives system (#348843) the
problem might be sorted out (as you probably know).