As part of our continuous integration job, we build RPMs from the master branch of our code repository. This very often means that the potential RPM requires a package that is not available in Fedora yet. Because of that we build the dependency RPMs during the process as well.

However to pass these dependencies to Mock, one has to either use Mockchain or prepare a custom Mock config. Using Mockchain is not always possible. E.g. "tito build --builder=mock" does not use Mockchain. "fedora-review" as well [1]. So, it sounds unreasonable to modify multiple tools in order to support Mochchain because of a feature that can be provided by Mock as well. OTOH, preparing custom configs has the drawback that Mock configs (and RPM repos) change from time to time and I'd have to watch the changes and incorporate them there.

So, since Mockchain already supports --addrepo, I think that there is no reason why Mock shouldn't support it as well.

But actually I don't care about the implementation. Mock can e.g. define an hardcoded path to a local repository where the user is supposed to place the dependencies. That would work for me as well.

[1] https://fedorahosted.org/FedoraReview/ticket/247