fix(runtime): block harness init until HMR is disabled

Ensure we only report harness ready after HMR has been disabled.

This prevents Metro from pushing updates mid-run if tests change during execution.

Author: bheemreddy-samsara

packages/runtime/src/__tests__/initialize.test.ts

@@ -15,8 +15,9 @@ describe('initialize', () => {
         // ok
       });
 
-    disableHMRWhenReady(disable, 50);
+    const promise = disableHMRWhenReady(disable, 50);
     await vi.runAllTimersAsync();
+    await promise;
 
     expect(disable).toHaveBeenCalledTimes(2);
   });

packages/runtime/src/disableHMRWhenReady.ts

@@ -3,18 +3,25 @@ export function disableHMRWhenReady(
   retriesLeft: number,
   schedule: (cb: () => void) => void = (cb) => setTimeout(cb, 0),
 ) {
-  try {
-    disable();
-  } catch (error) {
-    if (
-      retriesLeft > 0 &&
-      error instanceof Error &&
-      error.message.includes('Expected HMRClient.setup() call at startup.')
-    ) {
-      schedule(() => disableHMRWhenReady(disable, retriesLeft - 1, schedule));
-      return;
+  return new Promise<void>((resolve, reject) => {
+    function attempt(remaining: number) {
+      try {
+        disable();
+        resolve();
+      } catch (error) {
+        if (
+          remaining > 0 &&
+          error instanceof Error &&
+          error.message.includes('Expected HMRClient.setup() call at startup.')
+        ) {
+          schedule(() => attempt(remaining - 1));
+          return;
+        }
+
+        reject(error);
+      }
     }
 
-    throw error;
-  }
+    attempt(retriesLeft);
+  });
 }

packages/runtime/src/initialize.ts

@@ -22,11 +22,10 @@ const HMRClient =
 
 // Wait for HMRClient to be initialized
 setTimeout(() => {
-  disableHMRWhenReady(() => HMRClient.disable(), 50);
-
-  // Initialize the React Native Harness
-  void getClient().then((client) =>
-    client.rpc.reportReady(getDeviceDescriptor())
+  void disableHMRWhenReady(() => HMRClient.disable(), 50).then(() =>
+    getClient().then((client) =>
+      client.rpc.reportReady(getDeviceDescriptor())
+    )
   );
 });