I’ve come across a behavior in Nix I don’t understand (not the first time, but this one can’t figure out): say I have a pkgs.mkShell derivation assigned to devShell with buildInputs defined as a list with 7 elements, two of which are pkgs.lld_15 and pkgs.llvm_15. I want to define pkgs.writeShellApplication and reuse buildInputs from devShell as runtimeInputs. However, it turns out that pkgs.lld_15 and pkgs.llvm_15 are not passed and to have them available in pkgs.writeShellApplication I need to add them explicitly: runtimeInputs = devShell.buildInputs ++ [ pkgs.lld_15 pkgs.llvm_15 ];. Why?
IMO the behavior indicates, that they are somehow filtered out and when used in runtimeInputs definition they are not present in devShell.buildInputs list. In my understanding, in this scenario, buildInputs is just an ordinary attribute and is not processed in any way. Then what happens with these two derivations?