Description of problem: Please consider removing the Requires: /usr/sbin/sendmail line from mdadm's RPM spec file. Lots of packages are capable of sending mail, but mdadm is unusual in that it actually has a dependency on /usr/sbin/sendmail. I don't have an RPM-based MTA installed; I use a custom-built version of Postfix. Because of the /usr/sbin/sendmail dependency, whenever a new mdadm package comes out, I have to go in and manually install it with --nodeps. This gets old after a while; I'd rather be able to keep it up to date with "yum" like I do with every other package. Version-Release number of selected component (if applicable): mdadm-2.6.1-4.fc7 (and earlier versions, going back many years)
The dependency on /usr/sbin/sendmail is there because mdadm specifically calls that file and no other. It was previously a dependency on MTA and was changed during the merge review process. As far as your system requiring manual installation because you don't bother to build your custom postfix into an RPM before installing it, well, that's to be expected.
I understand that mdadm can call /usr/sbin/sendmail, and that in previous FC/RHEL releases the dependency was on "smtpdaemon" instead. My point is that virtually all other packages do not have such a dependency, despite many of them being capable of sending mail (this includes vixie-cron, smartd, and even mailx). # rpm -qa | wc -l 390 # rpm -q --whatrequires /usr/sbin/sendmail mdadm-2.6.1-4.fc7 # rpm -q --whatrequires smtpdaemon no package requires smtpdaemon mdadm's dependency on /usr/sbin/sendmail therefore strikes me as superfluous. It shouldn't require an MTA package to be installed just because it "can" send mail. Even if someone had no /usr/sbin/sendmail at all, the non-monitoring functionality of mdadm would still work fine, AFAICS.
Even though I closed this out as NOTABUG, I did in fact make the change. The mdadm-2.6.2-4.fc7 package in updates-testing has the requirement removed.