Vercel edge functions producing a null error from @sveltejs/kit next.433

[SG60]

Describe the bug

@sveltejs/kit next.433 (this PR: #6179) seems to have introduced a bug with Vercel edge functions. The edge functions consistently crash

Reproduction

1. kit 433 with Vercel edge functions: https://github.com/SG60/kit-433-error/tree/36670af2556b9b832b4b7fc47be807a7bc120e0d
   this has an error
2. kit 433 without edge functions: https://github.com/SG60/kit-433-error/tree/b2e212d73dd297ac54fece7ec8e834657b9967dc
   this works
3. kit downgraded to 432 with Vercel edge functions: https://github.com/SG60/kit-433-error/tree/c02648f00e9d9812b4dfdaa74a00cab0f93c930e
   this works

Logs

(These are from Vercel's function logs)

TypeError: Cannot read properties of null (reading 'handleError')
    at ../../../../.svelte-kit/output/server/index.js:2455:27
    at ../../../../.svelte-kit/output/server/index.js:2404:12

[GET] / reason=EDGE_FUNCTION_INVOCATION_FAILED, status=500, user_error=true

System Info

Vercel

Severity

blocking an upgrade

Additional Information

No response

[mquandalle]

I had a similar issue and had to update the @sveltejs/vercel-adapter to fix it.

[SG60]

Annoyingly I'm already using the newest version of vercel-adapter (next.68), so I don't think it's that.

[dennisregalado]

Using the newest version of the vercel-adapter & experiencing the same issue on Edge functions.

[jofan]

I have the same issue with Vercel and Netlify adaptors. @mquandalle Any tips on how to fix it?