Vercel ISR support doesn't seem to work/is very flaky

[zusorio]

Describe the bug

I followed the docs to set up vercel ISR in a test project, however that didn't seem to actually do anything.

Another project uses prerender = 'auto' but this seemed to make vercel cache the request indefinitely.

I then tried to make a reproduction with both no prerender and prerender = 'auto' in different routes, but with both routes present neither of them are cached.

I also have another more complex project that I originally wanted to use ISR for. In that project despite an identical setup ISR seems to work properly for the index route with prerender = 'auto'. However, it doesn't work for any API routes.

Reproduction

Not caching anything without prerender

https://sveltekit-isr-repro-682h0lk7v-zusor.vercel.app/
https://github.com/zusorio/sveltekit-isr-repro/tree/3d05c49c3f90e7c2a551e5b7b48de36a007e0cc5

Caching indefinitely with prerender = 'auto'

https://sveltekit-isr-repro-pmrfpyg4k-zusor.vercel.app/
https://github.com/zusorio/sveltekit-isr-repro/tree/38cc230ee687ea1be8b39eeaa0e6e7f149fb6f08

Caching nothing with and without prerender = 'auto'

https://sveltekit-isr-repro.vercel.app/
https://github.com/zusorio/sveltekit-isr-repro

Logs

No response

System Info

System:
    OS: Windows 10 10.0.22621
    CPU: (12) x64 AMD Ryzen 5 3600 6-Core Processor
    Memory: 3.13 GB / 15.95 GB
  Binaries:
    Node: 16.19.0 - C:\Program Files\nodejs\node.EXE
    npm: 8.19.3 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 110.0.5481.104
    Edge: Spartan (44.22621.1265.0), Chromium (110.0.1587.50)
    Internet Explorer: 11.0.22621.1
  npmPackages:
    @sveltejs/adapter-vercel: ^2.1.0 => 2.1.0
    @sveltejs/kit: ^1.5.0 => 1.8.3
    svelte: ^3.54.0 => 3.55.1
    vite: ^4.0.0 => 4.1.4

Severity

annoyance

Additional Information

No response

[tonprince]

@zusorio I am still unable to invalidate the cache manualy by calling the Sveltekit route with HEADER x-prerender-revalidate=TOKEN

How can I force the route to be regenerated?

[SchlammSpringer]

@zusorio I am still unable to invalidate the cache manualy by calling the Sveltekit route with HEADER x-prerender-revalidate=TOKEN

How can I force the route to be regenerated?

Same here. It is very flaky, if you always GET the page, a HTTP HEAD with the HEADER works, but if you POST, you can´t revalidate oder refresh the cache.