Upgrade React from `f0dfee38-20260529` to `43bcbf80-20260603` by vercel-release-bot · Pull Request #94440 · vercel/next.js

vercel-release-bot · 2026-06-03T20:05:56Z

diff facebook/react@f0dfee38...43bcbf80

React upstream changes

github-actions · 2026-06-03T20:06:23Z

Failing test suites

Commit: c5c5d64 | About building and testing Next.js

pnpm test-dev test/e2e/app-dir/cache-components-errors/cache-components-errors.test.ts (job)

Cache Components Errors > Dev > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should show a collapsed redbox error (DD)

Expand output

● Cache Components Errors › Dev › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should show a collapsed redbox error

expect(received).toMatchInlineSnapshot(snapshot)

Snapshot name: `Cache Components Errors Dev Error Attribution with Sync IO Unguarded RSC with guarded Client sync IO should show a collapsed redbox error 1`

- Snapshot  - 7
+ Received  + 7

  {
-   "code": "E1296",
-   "description": "Next.js encountered runtime data during prerendering.",
+   "code": "E1287",
+   "description": "Next.js encountered the unstable value new Date() in a Client Component.",
    "environmentLabel": "Server",
    "label": "Blocking Route",
-   "source": "app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (34:18) @ RequestData
- > 34 |   ;(await cookies()).get('foo')
-      |                  ^",
+   "source": "app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx (5:16) @ SyncIO
+ > 5 |   const data = new Date().toISOString()
+     |                ^",
    "stack": [
-     "RequestData app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (34:18)",
-     "Page app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (27:9)",
+     "SyncIO app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx (5:16)",
+     "Page app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (23:11)",
    ],
  }

  2372 |             const browser = await next.browser(pathname)
  2373 |
> 2374 |             await expect(browser).toDisplayCollapsedRedbox(`
       |                                   ^
  2375 |              {
  2376 |                "code": "E1296",
  2377 |                "description": "Next.js encountered runtime data during prerendering.",

  at Object.toDisplayCollapsedRedbox (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2374:35)

pnpm test-start test/production/middleware-prefetch/middleware-prefetch.test.ts (job)

Middleware Production Prefetch > does not prefetch provided path if it will be rewritten (DD)

Expand output

● Middleware Production Prefetch › does not prefetch provided path if it will be rewritten

expect(received).toBe(expected) // Object.is equality

Expected: false
Received: true

  43 |             src.includes('/ssg-page-2' + (process.env.NEXT_RSPACK ? '-' : ''))
  44 |         )
> 45 |       ).toBe(false)
     |         ^
  46 |     })
  47 |   })
  48 | })

  at toBe (production/middleware-prefetch/middleware-prefetch.test.ts:45:9)
  at retry (lib/next-test-utils.ts:867:14)
  at Object.<anonymous> (production/middleware-prefetch/middleware-prefetch.test.ts:34:5)

pnpm test-start test/e2e/app-dir/cache-components-errors/cache-components-errors.test.ts (job)

Cache Components Errors > Build With --prerender-debug > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should error the build with a reason related dynamic data (DD)
Cache Components Errors > Build Without --prerender-debug > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should error the build with a reason related dynamic data (DD)

Expand output

● Cache Components Errors › Build With --prerender-debug › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should error the build with a reason related dynamic data

expect(received).toMatchInlineSnapshot(snapshot)

Snapshot name: `Cache Components Errors Build With --prerender-debug Error Attribution with Sync IO Unguarded RSC with guarded Client sync IO should error the build with a reason related dynamic data 1`

- Snapshot  - 22
+ Received  + 20

- "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
-
- `fetch(...)`, `cookies()`, `headers()`, `params`, `searchParams`, or `connection()` accessed outside of `<Suspense>` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.
-
- Ways to fix this:
-   - [cache] Cache the data access with `"use cache"`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#cache-the-component-or-data
-   - [stream] Provide a placeholder with `<Suspense fallback={...}>` around the data access
+ "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered the unstable value `new Date()` in a Client Component.
+
+ This value would be evaluated during the prerender, instead of recomputed on each visit.
+
+ Ways to fix this:
+   - [stream] Wrap the Client Component in `<Suspense fallback={...}>`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#wrap-in-or-move-into-suspense
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#wrap-in-or-move-into-suspense
-   - [cache] If the runtime data is `params` and they're known, prerender them with `generateStaticParams`
+   - [defer] Move the read into a `useEffect` or event handler
-     https://nextjs.org/docs/messages/blocking-prerender-runtime#for-known-params-prerender
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#move-into-effect-or-event-handler
-   - [block] Set `export const unstable_instant = false` to silence this warning and allow a blocking route
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#allow-blocking-route
-     at RequestData (webpack:///app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:34:18)
+   - [measure] If the value is for telemetry, use a timing API such as `performance.now()`
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#for-telemetry-use-a-timing-api
+     at SyncIO (webpack:///app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx:5:16)
-     at Page (webpack:///app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:27:9)
+     at Page (webpack:///app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:23:11)
-   32 |
-   33 | async function RequestData() {
+   3 | export function SyncIO() {
+   4 |   // This is a sync IO access that should not cause an error
- > 34 |   ;(await cookies()).get('foo')
+ > 5 |   const data = new Date().toISOString()
-      |                  ^
+     |                ^
+   6 |
-   35 |   return (
+   7 |   return (
-   36 |     <div>
-   37 |       <h2>Request Data Access</h2>
+   8 |     <main>
  To debug the issue, start the app in development mode by running `next dev`, then open "/sync-attribution/unguarded-async-guarded-clientsync" in your browser to investigate the error.
  Error occurred prerendering page "/sync-attribution/unguarded-async-guarded-clientsync". Read more: https://nextjs.org/docs/messages/prerender-error

  > Export encountered errors on 1 path:
  	/sync-attribution/unguarded-async-guarded-clientsync/page: /sync-attribution/unguarded-async-guarded-clientsync"

  2461 |             } else {
  2462 |               if (isDebugPrerender) {
> 2463 |                 expect(output).toMatchInlineSnapshot(`
       |                                ^
  2464 |                  "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
  2465 |
  2466 |                  \`fetch(...)\`, \`cookies()\`, \`headers()\`, \`params\`, \`searchParams\`, or \`connection()\` accessed outside of \`<Suspense>\` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.

  at Object.toMatchInlineSnapshot (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2463:32)

● Cache Components Errors › Build Without --prerender-debug › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should error the build with a reason related dynamic data

expect(received).toInclude(expected)

Expected string to include:
  "Error: Route \"/sync-attribution/unguarded-async-guarded-clientsync\": Next.js encountered uncached or runtime data during prerendering."
Received:
  "Error: Route \"/sync-attribution/unguarded-async-guarded-clientsync\": Next.js encountered the unstable value `new Date()` in a Client Component.·
This value would be evaluated during the prerender, instead of recomputed on each visit.·
Ways to fix this:
  - [stream] Wrap the Client Component in `<Suspense fallback={...}>`
    https://nextjs.org/docs/messages/blocking-prerender-current-time-client#wrap-in-or-move-into-suspense
  - [defer] Move the read into a `useEffect` or event handler
    https://nextjs.org/docs/messages/blocking-prerender-current-time-client#move-into-effect-or-event-handler
  - [measure] If the value is for telemetry, use a timing API such as `performance.now()`
    https://nextjs.org/docs/messages/blocking-prerender-current-time-client#for-telemetry-use-a-timing-api
    at a (<next-dist-dir>)
To get a more detailed stack trace and pinpoint the issue, try one of the following:
  - Start the app in development mode by running `next dev`, then open \"/sync-attribution/unguarded-async-guarded-clientsync\" in your browser to investigate the error.
  - Rerun the production build with `next build --debug-prerender` to generate better stack traces.
Error occurred prerendering page \"/sync-attribution/unguarded-async-guarded-clientsync\". Read more: https://nextjs.org/docs/messages/prerender-error
Export encountered an error on /sync-attribution/unguarded-async-guarded-clientsync/page: /sync-attribution/unguarded-async-guarded-clientsync, exiting the build."

  2495 |                 // non-debug-prerender mode, so we don't assert on the stack
  2496 |                 // frames here.
> 2497 |                 expect(output).toInclude(
       |                                ^
  2498 |                   'Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.'
  2499 |                 )
  2500 |               }

  at Object.toInclude (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2497:32)

pnpm test-dev-turbo test/e2e/app-dir/cache-components-errors/cache-components-errors.test.ts (turbopack) (job)

Cache Components Errors > Dev > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should show a collapsed redbox error (DD)

Expand output

● Cache Components Errors › Dev › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should show a collapsed redbox error

expect(received).toMatchInlineSnapshot(snapshot)

Snapshot name: `Cache Components Errors Dev Error Attribution with Sync IO Unguarded RSC with guarded Client sync IO should show a collapsed redbox error 1`

- Snapshot  - 7
+ Received  + 7

  {
-   "code": "E1296",
-   "description": "Next.js encountered runtime data during prerendering.",
+   "code": "E1287",
+   "description": "Next.js encountered the unstable value new Date() in a Client Component.",
    "environmentLabel": "Server",
    "label": "Blocking Route",
-   "source": "app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (34:18) @ RequestData
- > 34 |   ;(await cookies()).get('foo')
-      |                  ^",
+   "source": "app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx (5:16) @ SyncIO
+ > 5 |   const data = new Date().toISOString()
+     |                ^",
    "stack": [
-     "RequestData app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (34:18)",
-     "Page app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (27:9)",
+     "SyncIO app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx (5:16)",
+     "Page app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx (23:11)",
    ],
  }

  2372 |             const browser = await next.browser(pathname)
  2373 |
> 2374 |             await expect(browser).toDisplayCollapsedRedbox(`
       |                                   ^
  2375 |              {
  2376 |                "code": "E1296",
  2377 |                "description": "Next.js encountered runtime data during prerendering.",

  at Object.toDisplayCollapsedRedbox (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2374:35)

pnpm test-start-turbo test/e2e/prerender.test.ts (turbopack) (job)

Prerender > should of formatted build output correctly (DD)

Expand output

● Prerender › should of formatted build output correctly

expect(received).toMatch(expected)

Expected pattern: /\+2 more paths/
Received string:  "▲ Next.js 16.3.0-canary.40 (Turbopack)
- Experiments (use with caution):
  ✓ strictRouteTypes (enabled by `__NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES`)·
  Running TypeScript ...
  Finished TypeScript in 207ms ...
  Creating an optimized production build ...
✓ Compiled successfully in 11.7s
  Collecting page data using 15 workers ...
  Generating static pages using 15 workers (0/50) ...
Warning: data for page \"/large-page-data\" is 256 kB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
  Generating static pages using 15 workers (12/50)··
  Generating static pages using 15 workers (24/50)··
  Generating static pages using 15 workers (37/50)··
Warning: data for page \"/blocking-fallback/[slug]\" (path \"/blocking-fallback/lots-of-data\") is 256 kB which exceeds the threshold of 128 kB, this amount of data can reduce performance.
See more info here: https://nextjs.org/docs/messages/large-page-data
getStaticProps test-errors-1
✓ Generating static pages using 15 workers (50/50) in 2.9s
  Finalizing page optimization ...·
Route (pages)                                                     Revalidate  Expire
┌ ● / (341 ms)                                                            2s      1y
├ ○ /404
├ ● /another (318 ms)                                                     1s      1y
├   /api-docs/[...slug] (432 ms)
│ └ ● /api-docs/first
├ ƒ /api/bad
├ ƒ /api/enable
├ ƒ /api/manual-revalidate
├ ƒ /bad-gssp
├ ƒ /bad-ssr
├   /blocking-fallback-once/[slug] (1320 ms)
│ └ ● /blocking-fallback-once/404-on-manual-revalidate (1320 ms)
├   /blocking-fallback-some/[slug] (2656 ms)                              1s      1y
│ ├ ● /blocking-fallback-some/a (1328 ms)
│ └ ● /blocking-fallback-some/b (1328 ms)
├   /blocking-fallback/[slug] (1176 ms)
│ ├ ● /blocking-fallback/test-errors-1 (1057 ms)
│ └ ● /blocking-fallback/lots-of-data
├ ● /blog (319 ms)                                                       10s      1y
├   /blog/[post] (1555 ms)                                               10s      1y
│ ├ ● /blog/post-1 (437 ms)
│ ├ ● /blog/post-2 (437 ms)
│ ├ ● /blog/[post3]
│ ├ ● /blog/post-4
│ └ ● /blog/post.1
├   /blog/[post]/[comment] (919 ms)                                       2s      1y
│ ├ ● /blog/post-1/comment-1 (304 ms)
│ └ ● /blog/post-2/comment-2
├   /catchall-explicit/[...slug] (2675 ms)                                1s      1y
│ ├ ● /catchall-explicit/first (453 ms)
│ ├ ● /catchall-explicit/second (447 ms)
│ ├ ● /catchall-explicit/another/value (445 ms)
│ ├ ● /catchall-explicit/hello/another (444 ms)
│ ├ ● /catchall-explicit/[first]/[second] (443 ms)
│ └ ● /catchall-explicit/[third]/[fourth] (443 ms)
├   /catchall-optional/[[...slug]]
│ ├ ● /catchall-optional
│ └ ● /catchall-optional/value
├   /catchall/[...slug] (681 ms)                                          1s      1y
│ ├ ● /catchall/first
│ ├ ● /catchall/second
│ ├ ● /catchall/another/value
│ └ ● /catchall/hello/another
├ ● /default-revalidate (341 ms)
├   /dynamic/[slug]
│ ├ ● /dynamic/[first]
│ └ ● /dynamic/[second]
├ ● /fallback-only/[slug] (341 ms)
├   /fallback-true/[slug] (423 ms)                                        2s      1y
│ └ ● /fallback-true/first
├   /lang/[lang]/about (963 ms)
│ ├ ● /lang/es/about (328 ms)
│ ├ ● /lang/fr/about (314 ms)
│ ├ ● /lang/de/about (313 ms)
│ └ ● /lang/en/about
├ ● /large-page-data (341 ms)
├ ƒ /large-page-data-ssr
├ ● /non-json-blocking/[p]
├ ● /non-json/[p] (326 ms)
├ ○ /normal (354 ms)
├ ● /preview (325 ms)
├ ● /something (325 ms)
├ ƒ /ssr
└ ● /user/[user]/profile (319 ms)·
○  (Static)   prerendered as static content
●  (SSG)      prerendered as static HTML (uses getStaticProps)
ƒ  (Dynamic)  server-rendered on demand·
▲ Next.js 16.3.0-canary.40
- Local:         http://localhost:33707
- Network:       http://172.18.0.2:33707
✓ Ready in 259ms
Error: such broken..

  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  getStaticProps random-path
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  getStaticProps blocked-create
  Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../.next/server/chunks/ssr/[root-of-the-server]__1nbk2_l._.js:1:35563)
  ⨯ Error: such broken..
  at l (../.next/server/chunks/ssr/[root-of-the-server]__0269546._.js:1:7506)
  at async q (../

... truncated ...

pnpm test-start-turbo test/e2e/app-dir/cache-components-errors/cache-components-errors.test.ts (turbopack) (job)

Cache Components Errors > Build With --prerender-debug > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should error the build with a reason related dynamic data (DD)
Cache Components Errors > Build Without --prerender-debug > Error Attribution with Sync IO > Unguarded RSC with guarded Client sync IO > should error the build with a reason related dynamic data (DD)

Expand output

● Cache Components Errors › Build With --prerender-debug › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should error the build with a reason related dynamic data

expect(received).toMatchInlineSnapshot(snapshot)

Snapshot name: `Cache Components Errors Build With --prerender-debug Error Attribution with Sync IO Unguarded RSC with guarded Client sync IO should error the build with a reason related dynamic data 1`

- Snapshot  - 22
+ Received  + 20

- "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
-
- `fetch(...)`, `cookies()`, `headers()`, `params`, `searchParams`, or `connection()` accessed outside of `<Suspense>` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.
-
- Ways to fix this:
-   - [cache] Cache the data access with `"use cache"`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#cache-the-component-or-data
-   - [stream] Provide a placeholder with `<Suspense fallback={...}>` around the data access
+ "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered the unstable value `new Date()` in a Client Component.
+
+ This value would be evaluated during the prerender, instead of recomputed on each visit.
+
+ Ways to fix this:
+   - [stream] Wrap the Client Component in `<Suspense fallback={...}>`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#wrap-in-or-move-into-suspense
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#wrap-in-or-move-into-suspense
-   - [cache] If the runtime data is `params` and they're known, prerender them with `generateStaticParams`
+   - [defer] Move the read into a `useEffect` or event handler
-     https://nextjs.org/docs/messages/blocking-prerender-runtime#for-known-params-prerender
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#move-into-effect-or-event-handler
-   - [block] Set `export const unstable_instant = false` to silence this warning and allow a blocking route
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#allow-blocking-route
-     at RequestData (app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:34:18)
+   - [measure] If the value is for telemetry, use a timing API such as `performance.now()`
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#for-telemetry-use-a-timing-api
+     at SyncIO (app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx:5:16)
-     at Page (app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:27:9)
+     at Page (app/sync-attribution/unguarded-async-guarded-clientsync/page.tsx:23:11)
-   32 |
-   33 | async function RequestData() {
+   3 | export function SyncIO() {
+   4 |   // This is a sync IO access that should not cause an error
- > 34 |   ;(await cookies()).get('foo')
+ > 5 |   const data = new Date().toISOString()
-      |                  ^
+     |                ^
+   6 |
-   35 |   return (
+   7 |   return (
-   36 |     <div>
-   37 |       <h2>Request Data Access</h2>
+   8 |     <main>
  To debug the issue, start the app in development mode by running `next dev`, then open "/sync-attribution/unguarded-async-guarded-clientsync" in your browser to investigate the error.
  Error occurred prerendering page "/sync-attribution/unguarded-async-guarded-clientsync". Read more: https://nextjs.org/docs/messages/prerender-error

  > Export encountered errors on 1 path:
  	/sync-attribution/unguarded-async-guarded-clientsync/page: /sync-attribution/unguarded-async-guarded-clientsync"

  2403 |             if (isTurbopack) {
  2404 |               if (isDebugPrerender) {
> 2405 |                 expect(output).toMatchInlineSnapshot(`
       |                                ^
  2406 |                  "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
  2407 |
  2408 |                  \`fetch(...)\`, \`cookies()\`, \`headers()\`, \`params\`, \`searchParams\`, or \`connection()\` accessed outside of \`<Suspense>\` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.

  at Object.toMatchInlineSnapshot (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2405:32)

● Cache Components Errors › Build Without --prerender-debug › Error Attribution with Sync IO › Unguarded RSC with guarded Client sync IO › should error the build with a reason related dynamic data

expect(received).toMatchInlineSnapshot(snapshot)

Snapshot name: `Cache Components Errors Build Without --prerender-debug Error Attribution with Sync IO Unguarded RSC with guarded Client sync IO should error the build with a reason related dynamic data 1`

- Snapshot  - 18
+ Received  + 19

- "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
-
- `fetch(...)`, `cookies()`, `headers()`, `params`, `searchParams`, or `connection()` accessed outside of `<Suspense>` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.
-
- Ways to fix this:
-   - [cache] Cache the data access with `"use cache"`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#cache-the-component-or-data
-   - [stream] Provide a placeholder with `<Suspense fallback={...}>` around the data access
+ "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered the unstable value `new Date()` in a Client Component.
+
+ This value would be evaluated during the prerender, instead of recomputed on each visit.
+
+ Ways to fix this:
+   - [stream] Wrap the Client Component in `<Suspense fallback={...}>`
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#wrap-in-or-move-into-suspense
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#wrap-in-or-move-into-suspense
-   - [cache] If the runtime data is `params` and they're known, prerender them with `generateStaticParams`
+   - [defer] Move the read into a `useEffect` or event handler
-     https://nextjs.org/docs/messages/blocking-prerender-runtime#for-known-params-prerender
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#move-into-effect-or-event-handler
-   - [block] Set `export const unstable_instant = false` to silence this warning and allow a blocking route
-     https://nextjs.org/docs/messages/blocking-prerender-dynamic#allow-blocking-route
-     at a (<anonymous>)
-     at main (<anonymous>)
-     at main (<anonymous>)
-     at body (<anonymous>)
-     at html (<anonymous>)
+   - [measure] If the value is for telemetry, use a timing API such as `performance.now()`
+     https://nextjs.org/docs/messages/blocking-prerender-current-time-client#for-telemetry-use-a-timing-api
+     at <unknown> (app/sync-attribution/unguarded-async-guarded-clientsync/client.tsx:5:16)
+   3 | export function SyncIO() {
+   4 |   // This is a sync IO access that should not cause an error
+ > 5 |   const data = new Date().toISOString()
+     |                ^
+   6 |
+   7 |   return (
+   8 |     <main>
  To get a more detailed stack trace and pinpoint the issue, try one of the following:
    - Start the app in development mode by running `next dev`, then open "/sync-attribution/unguarded-async-guarded-clientsync" in your browser to investigate the error.
    - Rerun the production build with `next build --debug-prerender` to generate better stack traces.
  Error occurred prerendering page "/sync-attribution/unguarded-async-guarded-clientsync". Read more: https://nextjs.org/docs/messages/prerender-error
  Export encountered an error on /sync-attribution/unguarded-async-guarded-clientsync/page: /sync-attribution/unguarded-async-guarded-clientsync, exiting the build."

  2433 |                 `)
  2434 |               } else {
> 2435 |                 expect(output).toMatchInlineSnapshot(`
       |                                ^
  2436 |                  "Error: Route "/sync-attribution/unguarded-async-guarded-clientsync": Next.js encountered uncached or runtime data during prerendering.
  2437 |
  2438 |                  \`fetch(...)\`, \`cookies()\`, \`headers()\`, \`params\`, \`searchParams\`, or \`connection()\` accessed outside of \`<Suspense>\` prevents the route from being prerendered, blocking the page load and leading to a slower user experience.

  at Object.toMatchInlineSnapshot (e2e/app-dir/cache-components-errors/cache-components-errors.test.ts:2435:32)

github-actions · 2026-06-03T20:06:25Z

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Update react@experimental

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eps1lon force-pushed the update/react/19.3.0-canary-43bcbf80-20260603 branch from 546fe9e to c5c5d64 Compare June 4, 2026 05:04

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Upgrade React from `f0dfee38-20260529` to `43bcbf80-20260603`#94440

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