Arch Linux

It should not depend on postfix, because /usr/sbin/sendmail is provided by many MTAs.

Then there should be an install script that would inform the user that (1) mailx needs an MTA and then (2) echo a list of MTA's.

(2) is not good, because there are many MTAs in different repos. What to do when there will be another MTA? Update mailx.install again?

I see your point... But how about this:

1. We put a provides=('something') in every MTA, where 'something' can be 'mta' or some other appropriate name.
2. We add 'mta' as a dependency of mailx: depends=('glibc' 'mta')

I think this is a better solution since (1) mailx does really need an MTA in order to function but (2) there are many available MTA's in different repos.

What do you think about that?

postfix's PKGBUILD already has provides=('smtp-server')
There is a problem with making mailx to depend on smtp-server: how pacman will choose which package to install? If I'm right, it will just refuse to install mailx when some package that provides smtp-server is not installed. :-/
Another problem is that mailx is on Base Install CD. It's there because it's a dependency for another package (I don't know why though). Adding some simple smtp-server as a dependency for mailx will be yet another unneeded dependency on _Base_ Install CD.

Oh.. I overlooked that provides in postfix... Anyway, mailx will be rendered useless without an smtp-server... So.. Including a package which doesn't work because of an unmet dependency doesn't make any sense. With that said, I think it is better to add "yet another unneeded dependency on _Base_ Install CD" (which is really a needed dependency) that to have a useless mailx package.

I agree with adding smtp-server as a dependency for mailx, but then I don't see the point of keeping mailx on Base CD as a logrotate dependency. Isn't logrotate working fine without mailx?

I just checked out Debian's package page for logrotate: "Logrotate allows for the automatic rotation compression, removal and mailing of log files". Maybe that's the reason why mailx is listed as a dependency. However, in Debian's logrotate page, mailx is listed only as a recommended package, which means that it isn't really a dependency. Then maybe we could just suggest/recommend the installation of mailx via the install script?

yes