Add note about beforeFiles continuing

[ijjk]

This adds a note explaining that beforeFiles continue instead of checking the filesystem/dynamic routes immediately like they do in afterFiles and fallback.

Documentation / Examples

• Make sure the linting passes

Closes: #26795

[threehams]

#26795 is about rewrites looping through all beforeFiles, then continuing on to match afterFiles despite already hitting a match. Is this intended? It complicates the approach used in #12848 to support white-label sites (requires additional rewrites for ambiguous routes), and doesn't seem to match the documentation added in this PR.

[ijjk]

@threehams looking at the reproduction provided in the mentioned issue the beforeFiles rewrite will not match before the afterFiles rewrites due to the destination in beforeFiles pointing to a dynamic route and dynamic routes aren't checked right after beforeFiles.

I added this note to mention the continuing behavior of beforeFiles, if there's anything we could add to make this more clear let me know. Potentially we could give more examples of when things are matched/checked 🤔

[threehams]

Let me see if I can get you a better reproduction. Should I comment on the same issue or open a new one?

[ijjk]

The existing reproduction explains the issue correctly, it's not a bug and is meant to match that way for a dynamic route. If you were to set this line to fallback rewrites instead it would work as fallback rewrites are run after checking dynamic routes and all Next.js paths, afterFiles comes before dynamic routes are checked.

If you were to change this line to point to a non-dynamic page instead it would also work since non-dynamic pages are checked before afterFiles rewrites.

Let me see if I can tweak this doc to explain this order a bit more

[ijjk]

@threehams I opened an additional PR here adding some additional context, let me know if this helps clear it up some more or if it could use some more information to help make this more clear