Constant for repo url

src/updater/update-helper.ts

@@ -9,6 +9,7 @@ interface HelperOptions {
   branch: string;
   from: string;
   to: string;
+  targetRef: string;
   parent: number;
   restart: boolean;
 }
@@ -34,14 +35,25 @@ function parseOptions(args: string[]): HelperOptions {
   const branch = values.get("--branch");
   const from = values.get("--from");
   const to = values.get("--to");
+  const targetRef = values.get("--target-ref");
   const parent = Number(values.get("--parent"));
-  if (!repo || !branch || !from || !to || !Number.isInteger(parent)) {
+  if (
+    !repo ||
+    !branch ||
+    !from ||
+    !to ||
+    !targetRef ||
+    !Number.isInteger(parent)
+  ) {
     throw new Error("Missing updater helper arguments.");
   }
   if (!/^[0-9a-f]{40,64}$/u.test(from) || !/^[0-9a-f]{40,64}$/u.test(to)) {
     throw new Error("Invalid updater commit identifiers.");
   }
-  return { repo, branch, from, to, parent, restart };
+  if (targetRef !== `refs/remotes/xo-updater/${branch}`) {
+    throw new Error("Invalid updater target reference.");
+  }
+  return { repo, branch, from, to, targetRef, parent, restart };
 }
 
 function run(command: string, args: string[], cwd: string): Promise<void> {
@@ -129,11 +141,7 @@ async function main(): Promise<void> {
     const [branch, head, target, status] = await Promise.all([
       capture("git", ["branch", "--show-current"], options.repo),
       capture("git", ["rev-parse", "HEAD"], options.repo),
-      capture(
-        "git",
-        ["rev-parse", `refs/remotes/origin/${options.branch}`],
-        options.repo,
-      ),
+      capture("git", ["rev-parse", options.targetRef], options.repo),
       capture("git", ["status", "--porcelain"], options.repo),
     ]);
     if (