Recently, I ran into breakage due to yaml-cpp-0.5.3 breaking
yaml-cpp-0.5.1's ABI. The breakage was due to upstream not maintaining
ABI compatibility (something that's very hard with some C++ libraries),
but recovering from it was pretty hard, due to EPEL not keeping old
packages around.
If old packages were kept around, we could just tell people to run "yum
downgrade yaml-cpp-0.5.1" and then pin that package, until the ABI issue
was resolved. As it was, we had to refer them to the package from koji,
which means that new installs become harder.
Can we change the policy to keep old packages in the repository, to
prevent this in the future?