Pulp

pulp_rpm_prerequisites exists because the installer has had a plugin neutral policy.

This policy was for very long misunderstood: It's not about avoiding favoritism to any plugins, it's about not tying the installer (which is tied to pulpcore releases) to plugin releases. So that say pulpcore 3.3 logic would be in pulp_installer 3.3 release, and so that pulp_cardboardbox 0.7 logic would be in the pulp_cardboardbox_prerequisites 0.7 role.

The team now agrees that this policy is counter-productive because:

1. Having a role in a separate repo (not part of the pulp_installer collection) is extra work for developers, and for users.
2. The only plugin that currently needs a prereq role, pulp_rpm, has version numbers and releases that correspond to pulpcore releases. pulp_rpm 3.3.z needs pulpcore 3.3.z, etc. So the pulp_rpm specific installation logic can be safely bundled in pulp_installer 99% of the time.