Check out other refs/* by commit if provided, fall back to ref (#1924)

src/ref-helper.ts

@@ -46,8 +46,8 @@ export async function getCheckoutInfo(
     result.ref = ref
   }
   // refs/
-  else if (upperRef.startsWith('REFS/') && commit) {
-    result.ref = commit
+  else if (upperRef.startsWith('REFS/')) {
+    result.ref = commit ? commit : ref
   }
   // Unqualified ref, check for a matching branch or tag
   else {