Dear fellow developers, I hope this will be trivial to most of you but after seeing bug #455900 and the vast majority of developers not even thinking twice before sedding their dep strings, I believe this needs some attention.
What do subslots do: You set a subslot to a package and every time said package subslot changes (e.g. with an update), others packages depending on it with a := dep will be rebuilt. Nothing more, nothing less. Now, this solves a real problem: haskell, perl and ocaml packages need to be rebuilt after updating their respective compiler/interpreter and, in some cases, even after updating the libraries they use. Subslots would make haskell-updater, perl-cleaner and ocaml-rebuild not needed in the future. You can also use subslots to notify an ABI change in a shared library, in order to avoid having to use preserve-libs or run revdep-rebuild. However, this week I had to rebuild webkit-gtk three or four times and libreoffice twice... If you want to notify ABI changes, then you should set subslot to something representing the ABI, $PV as subslot is most certainly wrong in that case. Subslot is *not* a substitute to checking your library ABI, checking if its reverse dependencies work fine after the update, and notifying upstream if something went wrong so they can make a quick release fixing their mistake. Subslot is also *not* a substitute to soname and ensuring ABI compatibility (at least forward) between libraries with the same major. Using subslot only to be on the safe side and forcing a rebuild of all the dependent packages because it is too much work to check the ABI and work with upstream is, IMHO, a serious QA issue. Thank you for your attention, Alexis.
