test(nextjs): Cover an ISR page that is prerendered again at runtime

The ISR shells of the e2e apps come from the build, where the SDK does not
run, so the tag assertions passed with or without the guard. A page with a
one second window makes the server prerender it again inside a request.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Author: chargome

dev-packages/e2e-tests/test-applications/nextjs-16/app/isr-test/runtime/page.tsx

@@ -0,0 +1,11 @@
+// A short revalidation window, so a test can make the server prerender this page again at runtime.
+export const revalidate = 1;
+
+export default function ISRRuntimePage() {
+  return (
+    <div>
+      <h1>ISR Runtime Page</h1>
+      <div id="isr-runtime-rendered-at">{Date.now()}</div>
+    </div>
+  );
+}

dev-packages/e2e-tests/test-applications/nextjs-16/tests/isr-routes.test.ts

@@ -92,3 +92,27 @@ test('ISR route should be identified correctly in the route manifest', async ({
   expect(span.name).toBe('/isr-test/:product');
   expect(span.attributes['sentry.segment.name.source']?.value).toBe('route');
 });
+
+test('does not carry trace meta tags on an ISR page that was prerendered again at runtime', async ({ page }) => {
+  test.skip(!isProductionBuild, 'ISR pages are only prerendered in production builds');
+
+  // The first visit serves the shell from the build. Once its revalidation window passed, a visit serves the stale
+  // shell and makes the server prerender the page again, inside that request, with the SDK running. The visits after
+  // that serve the shell from that prerender.
+  await page.goto('/isr-test/runtime');
+  const renderedAtBuild = await page.locator('#isr-runtime-rendered-at').textContent();
+
+  await expect
+    .poll(
+      async () => {
+        await page.waitForTimeout(1500);
+        await page.goto('/isr-test/runtime');
+        return page.locator('#isr-runtime-rendered-at').textContent();
+      },
+      { timeout: 30_000 },
+    )
+    .not.toBe(renderedAtBuild);
+
+  await expect(page.locator('meta[name="sentry-trace"]')).toHaveCount(0);
+  await expect(page.locator('meta[name="baggage"]')).toHaveCount(0);
+});