Bodhi policy for pushing updates to stable

[Kamil Paral]

> Hi all.
> 
> When upgrading F20 to F21 using FedUp, some users had a problem
> with some packages not being upgraded (e.g. [1]). The problem was
> caused by broken update path F20 -> F21.

Just a note: That problem is even more complex. Fedora Branched some has freeze periods, when you can't push any new updates into it, unless they have been approved as freeze exceptions. These freeze periods are quite long. If Bodhi enforced upgrade path, you would not be able to push updates into stable releases (i.e. when F21 was frozen, you wouldn't have been able to push updates to F20 and F19). Which is obviously not what we want, we want to freeze just the development version, not also stable versions.

So, enforcing upgrade path for stable releases sounds good. But when we add development releases into the mix, we need to break upgrade path in certain cases. And we probably need to come up with a different solution to ensure you can correctly upgrade to it on the release day (maybe by using yum distro-sync-like approach instead of yum-update-like approach?). We will need to deal with these problems as our automation coverage increases.