typstPackages: Make a dedicated Universe package builder

pkgs/by-name/ty/typst/build-universe-package.nix

@@ -2,31 +2,50 @@
   lib,
   buildTypstPackage,
   fetchzip,
-  # typstPackages from within the scope
-  packages,
-  hash,
-  description,
-  license,
-  typstDeps,
-  homepage ? null,
+  typstPackages,
 }:
-buildTypstPackage (finalAttrs: {
-  inherit pname version;
+lib.extendMkDerivation {
+  inheritFunctionArgs = false;
+  constructDrv = buildTypstPackage;
 
-  src = fetchzip {
-    inherit hash;
-    url = "https://packages.typst.org/preview/${finalAttrs.pname}-${finalAttrs.version}.tar.gz";
-    stripRoot = false;
-  };
+  excludeDrvArgNames = [
+    "description"
+    "hash"
+    "license"
+    "homepage"
+    "typstDeps"
+  ];
 
-  typstDeps = builtins.filter (x: x != null) (
-    lib.map (d: (lib.attrsets.attrByPath [ d ] null packages)) typstDeps
-  );
+  extendDrvArgs =
+    finalAttrs:
+    {
+      pname,
+      version,
+      description,
+      hash,
+      license,
+      homepage ? null,
+      typstDeps ? [ ],
+    }:
+    {
+      src = fetchzip {
+        inherit hash;
+        url = "https://packages.typst.org/preview/${finalAttrs.pname}-${finalAttrs.version}.tar.gz";
+        stripRoot = false;
+      };
 
-  meta = {
-    inherit description;
-    maintainers = with lib.maintainers; [ cherrypiejam ];
-    license = lib.map (lib.flip lib.getAttr lib.licensesSpdx) license;
-  }
-  // (if homepage != null then { inherit homepage; } else { });
-})
+      typstDeps = builtins.filter (x: x != null) (
+        lib.map (d: (lib.attrsets.attrByPath [ d ] null typstPackages)) typstDeps
+      );
+
+      meta = {
+        inherit description;
+        maintainers = with lib.maintainers; [
+          cherrypiejam
+          RossSmyth
+        ];
+        license = lib.map (lib.flip lib.getAttr lib.licensesSpdx) license;
+      }
+      // lib.optionalAttrs (homepage != null) { inherit homepage; };
+    };
+}

pkgs/by-name/ty/typst/typst-packages.nix

@@ -9,6 +9,10 @@ let
 in
 lib.makeScope newScope (
   self:
+  let
+    # Not public, so do not expose to the package set
+    buildUniversePackage = self.callPackage ./build-universe-package.nix { typstPackages = self; };
+  in
   lib.foldlAttrs (
     packageSet: pname: versionSet:
     packageSet
@@ -16,7 +20,8 @@ lib.makeScope newScope (
       subPackageSet: version: packageSpec:
       subPackageSet
       // {
-        ${toPackageName pname version} = self.callPackage ./build-universe-package.nix {
+        ${toPackageName pname version} = buildUniversePackage {
+          inherit pname version;
           inherit (packageSpec)
             hash
             description