Commit 1bec8475 authored by Ben Siraphob's avatar Ben Siraphob
Browse files

lib/modules: skip optional + ++ in evalOptionValue when no default 

Replace `(optional (opt ? default) { ... }) ++ defs` with a direct
if/then/else. When the option has no default, this skips both the
list allocation and the ++ concat entirely. Most options do have
defaults, but even then we avoid the `optional` function call overhead
(closure + env allocation).

On NixOS minimal eval: -45K function calls (-0.93%), -3.7K list
concats (-1.93%).
parent 4ed2dff2

lib/modules.nix

+10 −5
Original line number Diff line number Diff line
@@ -1121,11 +1121,16 @@ let 
    let

      # Add in the default value for this option, if any.

      defs' =

        (optional (opt ? default) {

        if opt ? default then

          [

            {

              file = head opt.declarations;

              value = mkOptionDefault opt.default;

        })

        ++ defs;

            }

          ]

          ++ defs

        else

          defs;



      # Handle properties, check types, and merge everything together.

      res =