test(mobile): reload before each route measurement

Opening the root link does not pop the stack, so the second and later runs only
refocused the screen they meant to mount.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: juliusmarminge

apps/mobile/scripts/measure-renders.mts

@@ -249,22 +249,24 @@ const measureStreamReply = Effect.fn("measure.streamReply")(function* (
   return { report, stillStreaming: streamingItem(after) !== undefined };
 }, Effect.scoped);
 
-/** Opens a screen from Home and records its mount and data settling. */
+/** Opens a screen from a freshly loaded Home and records its mount and data settling. */
 const measureRouteOpen = Effect.fn("measure.routeOpen")(function* (
   options: Options,
   route: string,
   run: number,
 ) {
+  // A link to an already-open screen only refocuses it, so each run starts from a reload.
+  yield* Effect.scoped(
+    Effect.flatMap(connectInspector(options.metro), (evaluate) =>
+      evaluate("__t3RenderCounterReload()"),
+    ),
+  );
+  yield* Effect.sleep("15 seconds");
   const evaluate = yield* connectInspector(options.metro);
-  const open = (path: string) =>
-    evaluate(
-      `__t3RenderCounterOpen(${encodeJson(`${options.scheme}://${path.replace(/^\//, "")}`)})`,
-    );
-  // Each run mounts the screen fresh rather than refocusing the previous one.
-  yield* open("");
-  yield* Effect.sleep("3 seconds");
   yield* evaluate("__t3RenderCounterStart()");
-  yield* open(route);
+  yield* evaluate(
+    `__t3RenderCounterOpen(${encodeJson(`${options.scheme}://${route.replace(/^\//, "")}`)})`,
+  );
   yield* Effect.sleep(`${options.windowSeconds} seconds`);
   const report = yield* decodeReport(yield* evaluate("JSON.stringify(__t3RenderCounterStop())"));
   if (report.commits === 0)

apps/mobile/src/features/development/render-counter.ts

@@ -151,6 +151,12 @@ Object.assign(globalThis, {
     void Linking.openURL(url);
     return true;
   },
+  /** Restarts the JS app on Home; deferred so the inspector call can reply first. */
+  __t3RenderCounterReload() {
+    const { DevSettings } = require("react-native") as typeof import("react-native");
+    setTimeout(() => DevSettings.reload(), 100);
+    return true;
+  },
   __t3RenderCounterStart() {
     state.commits = 0;
     state.counts = new Map();

docs/internals/mobile-development.md

@@ -58,7 +58,7 @@ node apps/mobile/scripts/measure-renders.mts --server <server-origin> --token <t
   --metro http://<metro-lan-host>:8081 --project-root <scratch-dir>
 ```
 
-`--route /settings/usage` instead opens that app path from Home and records a 6 s window over
+`--route /settings/usage` instead reloads the app, opens that path from Home and records a 6 s window over
 mount and data settling, with no provider turn and no `--server`, `--token` or `--project-root`.
 
 Compare before and after on the same base, on the same device, with the median of three runs.