scarab: add custom updateScript

pkgs/tools/games/scarab/default.nix

@@ -70,6 +70,8 @@ buildDotnetModule rec {
     categories = [ "Game" ];
   })];
 
+  passthru.updateScript = ./update.sh;
+
   meta = with lib; {
     description = "Hollow Knight mod installer and manager";
     homepage = "https://github.com/fifty-six/Scarab";

pkgs/tools/games/scarab/update.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p curl jq common-updater-scripts
+set -euo pipefail
+
+new_version="$(curl -s "https://api.github.com/repos/fifty-six/Scarab/releases?per_page=1" | jq -r '.[0].name')"
+new_version=${new_version#"v"}
+old_version="$(sed -nE 's/^\s*version = "([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)";$/\1/p' ./default.nix)"
+
+if [[ "$new_version" == "$old_version" ]]; then
+    echo "Up to date"
+    exit 0
+fi
+
+update-source-version scarab "$new_version"
+
+$(nix-build . -A scarab.fetch-deps --no-out-link)