Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: data-douser

scripts/upgrade-packs.sh

@@ -103,8 +103,9 @@ pin_upstream_deps() {
     return
   fi
 
-  ## Run codeql pack upgrade to resolve the latest compatible versions
-  codeql pack upgrade -- "${pack_dir}" >/dev/null 2>&1
+  ## Run codeql pack upgrade to resolve the latest compatible versions.
+  ## Suppress normal output but keep stderr so failures are diagnosable.
+  codeql pack upgrade -- "${pack_dir}" >/dev/null
 
   while IFS= read -r dep_line; do
     ## Extract dep name and current version value
@@ -127,8 +128,14 @@ pin_upstream_deps() {
     if [[ -z "${resolved_version}" ]]; then
       local tmp_dir
       tmp_dir=$(mktemp -d)
-      ## Ensure the temp dir is removed on early exit (e.g. codeql pack upgrade failure)
-      trap 'rm -rf "${tmp_dir}"' RETURN
+      ## Ensure the temp dir is removed even on early exit (e.g. codeql pack upgrade failure)
+      local previous_exit_trap
+      previous_exit_trap=$(trap -p EXIT | sed -E "s/^trap -- '(.*)' EXIT$/\1/" || true)
+      if [[ -n "${previous_exit_trap}" ]]; then
+        trap 'rm -rf "'"${tmp_dir}"'"; '"${previous_exit_trap}" EXIT
+      else
+        trap 'rm -rf "'"${tmp_dir}"'"' EXIT
+      fi
       local extractor
       extractor=$(grep -m1 "^extractor:" "${qlpack_yml}" | awk '{print $2}' || echo "javascript")
       cat > "${tmp_dir}/qlpack.yml" <<TMPEOF