luarocks: can be embedded with lua.withPackages

lua.withPackages only brings packages that have passthru.luaModule, which was not the case of luarocks (because it's built differently than other lua packages). We call toLuaModule on luarocks so that it is brought in a lua.withPackages call

pkgs/development/lua-modules/lib.nix

@@ -89,7 +89,13 @@ rec {
     , rocksSubdir
     }: let
       rocksTrees = lib.imap0
-        (i: dep: { name = "dep-${toString i}"; root = "${dep}"; rocks_dir = "${dep}/${dep.rocksSubdir}"; })
+        (i: dep: {
+          name = "dep-${toString i}";
+          root = "${dep}";
+          # packages built by buildLuaPackage or luarocks doesn't contain rocksSubdir
+          # hence a default here
+          rocks_dir = if dep ? rocksSubdir then "${dep}/${dep.rocksSubdir}" else "${dep.pname}-${dep.version}-rocks";
+        })
         requiredLuaRocks;
 
       # Explicitly point luarocks to the relevant locations for multiple-output

pkgs/top-level/lua-packages.nix

@@ -54,10 +54,10 @@ rec {
     inherit (pkgs.buildPackages) makeSetupHook makeWrapper;
   };
 
-  luarocks = callPackage ../development/tools/misc/luarocks/default.nix { };
+  luarocks = toLuaModule (callPackage ../development/tools/misc/luarocks/default.nix { });
 
   # a fork of luarocks used to generate nix lua derivations from rockspecs
-  luarocks-nix = callPackage ../development/tools/misc/luarocks/luarocks-nix.nix { };
+  luarocks-nix = toLuaModule (callPackage ../development/tools/misc/luarocks/luarocks-nix.nix { });
 
  lua-resty-core = callPackage ({ fetchFromGitHub }: buildLuaPackage rec {
     pname = "lua-resty-core";