Invalidating client side router cache after server data mutation

[mdj-uk]

It seems that in next 16 with cache components enabled if I mutate server data in a server action and call updateTag (cached data) or refresh (uncached data) to immediately update the UI, the entire client side router cache is invalidated and it will perform a new prefetch for every link in the viewport (except those with prefetch={false}).

So every time I mutate data I get loads of prefetching, including for pages which do not depend on the updated data, and even for static pages.

Is this correct? Is it documented anywhere? Apologies if I've missed it but I don't see anything in the docs pages for refresh or updateTag or the prefetching guide.

I seem to recall there used to be warnings in the docs that this would happen after revalidateTag but that it was a temporary measure and in future only the affected pages would be cleared from the router cache. (I can't find that note any more, it's possible I'm misremembering)

[icyJoseph]

Yes this is still a thing, https://nextjs.org/docs/app/api-reference/functions/revalidatePath:

This behavior is temporary and will be updated in the future to apply only to the specific path.

• next.js/packages/next/src/client/components/segment-cache-impl/cache.ts

  Lines 319 to 325 in d0d9466

  	/**
  	* Used to clear the client prefetch cache when a server action calls
  	* revalidatePath or revalidateTag. Eventually we will support only clearing the
  	* segments that were actually affected, but there's more work to be done on the
  	* server before the client is able to do this correctly.
  	*/
  	export function revalidateEntireCache(

AFAIK, the intention is to eventually indeed, only invalidate the relevant entries.

I'll make some time to add a note to updateTag and revalidateTag, I don't remember right now, but there might have been an effort to land this in 16. Which is why it didn't end up surfaced for the tag functions.

[mdj-uk]

Thanks!