Missing Cache-Control header in /404 rewrite response

[thomasdax98]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/nextjs-404-missing-cache-control-xvggzv

To Reproduce

1. Go to terminal
2. Stop Dev server
3. Start Next in production mode: npm run build && npm start
4. Execute curl -I http://localhost:3000/example

Current vs. Expected behavior

Current behavior

The response doesn't include a Cache-Control header:

Expected behavior

The reponse should include an explicit Cache-Control header. I propose private, no-cache, no-store, max-age=0, must-revalidate to avoid caching.

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Sun Aug  6 20:05:33 UTC 2023
  Available memory (MB): 4242
  Available CPU cores: 2
Binaries:
  Node: 20.12.0
  npm: 10.5.0
  Yarn: 1.22.19
  pnpm: 8.15.6
Relevant Packages:
  next: 15.1.7 // Latest available version is detected (15.1.7).
  eslint-config-next: 15.0.4
  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)

Not sure

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

next build (local), next start (local), Other (Deployed)

Additional context

I tested this behavior in Next v14 and v15.

My original motivation for rewriting a path to /404 was rewriting non-existing /_next/static URLs because for those we skip the middleware and they caused 500 errors in my page.tsx.

[samcx]

@thomasdax98 Not exactly sure yet why rewrites cause the /404 path to miss a Cache-Control, but also I don't think you should need to rewrite non-existing /_next/static URLs (what 500 errors are you seeing?).

[thomasdax98]

@samcx

but also I don't think you should need to rewrite non-existing /_next/static URLs (what 500 errors are you seeing?).

That's somewhat specific to our system: We host multiple different sites on different domains within one Next.js app. We normally rewrite the URL in the middleware and prefix the URL with "scope" information based on the domain. This allows us to access the domain via the params. Then some configuration is loaded based on this scope.

Normally a request looks something like this: https://domain-one.com/en/my-page. The URL is rewritten to /domain-one/en/my-page -> the scope is { domain: "domain-one" }. In page.tsx we load the config based on this scope:

const config = getSiteConfigForScope({ domain: "domain-one" });

getSiteConfigForScope throws an error if there is no config for the scope -> this is the 500

For /_next/static, we skip the middleware to avoid the URL rewrite. If a /_next/static URL doesn't exist and it's routed to our page.tsx, this happens:

const config = getSiteConfigForScope({ domain: "_next" });

There is no config for this "scope" -> 500