https://sn.1w6.org/file/clacke-20180403T035109-g6czk69.html
Oh, ok! I thought overrideDerivation overrode the mkDerivation call, but it actually overrides the underlying derivation. Overriding the mkDerivation call is what overrideAttrs does. Basically I always want overrideAttrs and I've always been using overrideDerivation. A lot of the times it makes no difference, but then you suddenly get really confused.