"Filling a cache during prerender timed out" error while building the app with dynamic routes

[ketchuup]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/dynamic-routes-in-dynamicio-kxp6zr

To Reproduce

1. Open the provided link to CodeSandbox.
2. Run pnpm run build.
3. Observe the following error:

Error: Filling a cache during prerender timed out, likely because request-specific arguments such as params, searchParams, cookies() or dynamic data were used inside "use cache".
    at 6274 (.next/server/app/[slug]/page.js:1:3742)
    at Function.t (.next/server/webpack-runtime.js:1:127) {
  digest: 'USE_CACHE_TIMEOUT'
}
Error occurred prerendering page "/[slug]". Read more: https://nextjs.org/docs/messages/prerender-error
Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.
Export encountered an error on /[slug]/page: /[slug], exiting the build.
 ⨯ Static worker exited with code: 1 and signal: null

---

1. Remove "use cache"; from app/[slug]/page.tsx.
2. Run pnpm run build.
3. Observe the following error:

Error occurred prerendering page "/[slug]". Read more: https://nextjs.org/docs/messages/prerender-error
Error: Route "/[slug]" has a `generateViewport` that depends on Request data (`cookies()`, etc...) or external data (`fetch(...)`, etc...) but the rest of the route was static or only used cached data (`"use cache"`). If you expected this route to be prerenderable update your `generateViewport` to not use Request data and only use cached external data. Otherwise, add `await connection()` somewhere within this route to indicate explicitly it should not be prerendered.
Export encountered an error on /[slug]/page: /[slug], exiting the build.
 ⨯ Static worker exited with code: 1 and signal: null

Current vs. Expected behavior

Expected behavior:

1. /[slug] dynamic route should be rendered statically at build time or at data revalidation.
2. params should not be request-specific argument as error tells.

Current behavior:

1. next build tries to build /[slug] dynamic route, however, it gets Filling a cache during prerender timed out, ... error.
2. params are request-specific argument.
3. await params requires to use either "use cache"; or Suspense boundary.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Enterprise LTSC 2021
  Available memory (MB): 15734
  Available CPU cores: 12
Binaries:
  Node: 22.12.0
  npm: 11.0.0
  Yarn: N/A
  pnpm: 9.15.4
Relevant Packages:
  next: 15.2.0-canary.27 // Latest available version is detected (15.2.0-canary.27).
  eslint-config-next: N/A
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.7.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

dynamicIO

Which stage(s) are affected? (Select all that apply)

next build (local)

Additional context

Overall, I have no idea how to do dynamic routes with dynamicIO enabled and without using a Suspense boundary.

My goal is to render all the routes statically at build-time, including dynamic ones (using generateStaticParams).
If there is no pre-rendered paged for requested dynamic route, I want it to be rendered on demand and cached for future requests.