All projects in oVirt CI are built today post merge, using the 'build-artifacts' stage from oVirt's CI standards. This ensures that all oVirt projects are built and deployed to oVirt repositories and can be consumed by CI jobs, developers or oVirt users.
However, on some occasions a developer might need to build his project from an open patch. Developers need this capability in order to to examine the effects of their changes on a full oVirt installation before merging those changes. On some cases developers may even want to hand over packages based on un-merged patches to the QE team to verify that a given change will fix some complex issue or to preview a new feature on its early stages of development.