test(tanstackstart): Add TanStack Start on Cloudflare Workers test app (#20649)

Adds an e2e test application for TanStack Start deployed to Cloudflare
Workers using `@sentry/cloudflare`. The setup uses a custom server entry
point that wraps the TanStack Start handler with `Sentry.withSentry`.

Unfortunately the type safety is not great yet with `Sentry.withSentry`
and TanStack Start, so this needs to be adapted in another PR (or in v11
if it is not yet possible).

Closes #18669

Author: JPeer264

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/.gitignore

@@ -0,0 +1,6 @@
+node_modules
+dist
+.output
+.wrangler
+.tanstack
+src/routeTree.gen.ts

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/package.json

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+{
+  "name": "tanstackstart-react-cloudflare",
+  "private": true,
+  "version": "0.0.1",
+  "type": "module",
+  "scripts": {
+    "dev": "vite dev",
+    "build": "vite build",
+    "preview": "wrangler dev --var E2E_TEST_DSN:$E2E_TEST_DSN --log-level=$(test $CI && echo 'none' || echo 'log')",
+    "test": "playwright test",
+    "typecheck": "tsc --noEmit",
+    "test:build": "pnpm install && pnpm build",
+    "test:assert": "pnpm typecheck && pnpm test"
+  },
+  "dependencies": {
+    "@sentry/browser": "file:../../packed/sentry-browser-packed.tgz",
+    "@sentry/cloudflare": "file:../../packed/sentry-cloudflare-packed.tgz",
+    "@sentry/tanstackstart-react": "file:../../packed/sentry-tanstackstart-react-packed.tgz",
+    "@tanstack/react-start": "^1.136.0",
+    "@tanstack/react-router": "^1.136.0",
+    "react": "^19.2.0",
+    "react-dom": "^19.2.0"
+  },
+  "devDependencies": {
+    "@cloudflare/vite-plugin": "^1.35.0",
+    "@cloudflare/workers-types": "^4.20260504.0",
+    "@playwright/test": "~1.56.0",
+    "@sentry-internal/test-utils": "link:../../../test-utils",
+    "@types/react": "^19.2.0",
+    "@types/react-dom": "^19.2.0",
+    "@vitejs/plugin-react": "^4.5.0",
+    "typescript": "^5.9.0",
+    "vite": "7.3.1",
+    "vite-tsconfig-paths": "^5.1.4",
+    "wrangler": "^4.68.1"
+  },
+  "volta": {
+    "node": "24.15.0",
+    "extends": "../../package.json"
+  },
+  "sentryTest": {
+    "optional": true
+  }
+}

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/playwright.config.ts

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+import { getPlaywrightConfig } from '@sentry-internal/test-utils';
+
+export default getPlaywrightConfig({
+  startCommand: 'pnpm preview',
+  port: 8787,
+});

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/env.d.ts

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+interface Env {
+  E2E_TEST_DSN: string;
+}

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/router.tsx

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+import * as Sentry from '@sentry/browser';
+import { createRouter } from '@tanstack/react-router';
+import { routeTree } from './routeTree.gen';
+
+export const getRouter = () => {
+  const router = createRouter({
+    routeTree,
+    scrollRestoration: true,
+  });
+
+  if (!router.isServer) {
+    Sentry.init({
+      environment: 'qa',
+      dsn: 'https://public@dsn.ingest.sentry.io/1337',
+      integrations: [Sentry.browserTracingIntegration()],
+      tracesSampleRate: 1.0,
+      release: 'e2e-test',
+      tunnel: 'http://localhost:3031/',
+    });
+  }
+
+  return router;
+};

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/routes/__root.tsx

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+import type { ReactNode } from 'react';
+import { Outlet, createRootRoute, HeadContent, Scripts } from '@tanstack/react-router';
+import { getTraceData } from '@sentry/tanstackstart-react';
+
+export const Route = createRootRoute({
+  head: () => {
+    const traceData = getTraceData();
+    const sentryMeta = Object.entries(traceData).map(([key, value]) => ({
+      name: key,
+      content: value,
+    }));
+
+    return {
+      meta: [
+        {
+          charSet: 'utf-8',
+        },
+        {
+          name: 'viewport',
+          content: 'width=device-width, initial-scale=1',
+        },
+        {
+          title: 'TanStack Start Cloudflare E2E Test',
+        },
+        ...sentryMeta,
+      ],
+    };
+  },
+  component: RootComponent,
+});
+
+function RootComponent() {
+  return (
+    <RootDocument>
+      <Outlet />
+    </RootDocument>
+  );
+}
+
+function RootDocument({ children }: Readonly<{ children: ReactNode }>) {
+  return (
+    <html>
+      <head>
+        <HeadContent />
+      </head>
+      <body>
+        {children}
+        <Scripts />
+      </body>
+    </html>
+  );
+}

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/routes/api.error.ts

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+import { createFileRoute } from '@tanstack/react-router';
+
+export const Route = createFileRoute('/api/error')({
+  server: {
+    handlers: {
+      GET: async () => {
+        throw new Error('Sentry API Route Test Error');
+      },
+    },
+  },
+});

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/routes/api.flush.ts

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+import { createFileRoute } from '@tanstack/react-router';
+import { flush } from '@sentry/cloudflare';
+
+export const Route = createFileRoute('/api/flush')({
+  server: {
+    handlers: {
+      GET: async () => {
+        await flush();
+        return new Response('ok');
+      },
+    },
+  },
+});

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/routes/index.tsx

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+import { createFileRoute } from '@tanstack/react-router';
+import { createServerFn } from '@tanstack/react-start';
+
+const throwServerError = createServerFn().handler(async () => {
+  throw new Error('Sentry Server Function Test Error');
+});
+
+export const Route = createFileRoute('/')({
+  component: Home,
+});
+
+function Home() {
+  return (
+    <div>
+      <h1>TanStack Start Cloudflare E2E Test</h1>
+      <button
+        id="client-error-btn"
+        type="button"
+        onClick={() => {
+          throw new Error('Sentry Client Test Error');
+        }}
+      >
+        Break the client
+      </button>
+      <button
+        id="throw-server-fn-btn"
+        type="button"
+        onClick={async () => {
+          await throwServerError();
+        }}
+      >
+        Break server function
+      </button>
+      <button
+        id="api-error-btn"
+        type="button"
+        onClick={async () => {
+          await fetch('/api/error');
+        }}
+      >
+        Break API route
+      </button>
+    </div>
+  );
+}

dev-packages/e2e-tests/test-applications/tanstackstart-react-cloudflare/src/routes/ssr-error.tsx

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+import { createFileRoute } from '@tanstack/react-router';
+
+export const Route = createFileRoute('/ssr-error')({
+  loader: () => {
+    throw new Error('Sentry SSR Test Error');
+  },
+  component: () => <div>SSR Error Page</div>,
+});