starship: build-time nushell config generation

modules/programs/starship.nix

@@ -6,8 +6,6 @@ let
 
   tomlFormat = pkgs.formats.toml { };
 
-  starshipCmd = "${config.home.profileDirectory}/bin/starship";
-
   initFish =
     if cfg.enableInteractive then "interactiveShellInit" else "shellInitLast";
 in {
@@ -100,26 +98,26 @@ in {
 
     programs.bash.initExtra = mkIf cfg.enableBashIntegration ''
       if [[ $TERM != "dumb" ]]; then
-        eval "$(${starshipCmd} init bash --print-full-init)"
+        eval "$(${lib.getExe cfg.package} init bash --print-full-init)"
       fi
     '';
 
     programs.zsh.initContent = mkIf cfg.enableZshIntegration ''
       if [[ $TERM != "dumb" ]]; then
-        eval "$(${starshipCmd} init zsh)"
+        eval "$(${lib.getExe cfg.package} init zsh)"
       fi
     '';
 
     programs.fish.${initFish} = mkIf cfg.enableFishIntegration ''
       if test "$TERM" != "dumb"
-        ${starshipCmd} init fish | source
+        ${lib.getExe cfg.package} init fish | source
         ${lib.optionalString cfg.enableTransience "enable_transience"}
       end
     '';
 
     programs.ion.initExtra = mkIf cfg.enableIonIntegration ''
       if test $TERM != "dumb"
-        eval $(${starshipCmd} init ion)
+        eval $(${lib.getExe cfg.package} init ion)
       end
     '';
 
@@ -128,15 +126,12 @@ in {
       # conditionally setting (global) environment variables, which is why the
       # check for terminal compatibility (as seen above for the other shells) is
       # not done here.
-      extraEnv = ''
-        let starship_cache = "${config.xdg.cacheHome}/starship"
-        if not ($starship_cache | path exists) {
-          mkdir $starship_cache
-        }
-        ${starshipCmd} init nu | save --force ${config.xdg.cacheHome}/starship/init.nu
-      '';
       extraConfig = ''
-        use ${config.xdg.cacheHome}/starship/init.nu
+        use ${
+          pkgs.runCommand "starship-nushell-config" { } ''
+            ${lib.getExe cfg.package} init nu >> "$out"
+          ''
+        }
       '';
     };
   };