@sveltejs/adapter-vercel v5.9.0 causes build failure

[awei82]

Describe the bug

My sveltekit app is failing to build with the vercel adapter on version 5.9.0. (see logs below)

This error does not occur when I'm on version 5.8.2.

Suspect commit: #13899

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-x8nj1thf

• @sveltejs/adapter-vercel pinned to 5.9.0
• svelte.config.js set to 'adapter-vercel'

run npm run build in terminal -> error

Logs

> Using @sveltejs/adapter-vercel
error during build:
TypeError: builder.hasServerInstrumentationFile is not a function
    at generate_serverless_function (file:///Users/andrewwei/crates/crates-v2/node_modules/@sveltejs/adapter-vercel/index.js:103:17)
    at adapt (file:///Users/andrewwei/crates/crates-v2/node_modules/@sveltejs/adapter-vercel/index.js:368:11)
    at adapt (file:///Users/andrewwei/crates/crates-v2/node_modules/@sveltejs/kit/src/core/adapt/index.js:38:8)
    at finalise (file:///Users/andrewwei/crates/crates-v2/node_modules/@sveltejs/kit/src/exports/vite/index.js:1074:13)
    at async Object.handler (file:///Users/andrewwei/crates/crates-v2/node_modules/@sveltejs/kit/src/exports/vite/index.js:1104:5)
    at async PluginDriver.hookParallel (file:///Users/andrewwei/crates/crates-v2/node_modules/rollup/dist/es/shared/node-entry.js:22192:17)
    at async Object.close (file:///Users/andrewwei/crates/crates-v2/node_modules/rollup/dist/es/shared/node-entry.js:23206:13)
    at async buildEnvironment (file:///Users/andrewwei/crates/crates-v2/node_modules/vite/dist/node/chunks/dep-DBxKXgDP.js:46229:17)
    at async Object.defaultBuildApp [as buildApp] (file:///Users/andrewwei/crates/crates-v2/node_modules/vite/dist/node/chunks/dep-DBxKXgDP.js:46684:5)
    at async CAC.<anonymous> (file:///Users/andrewwei/crates/crates-v2/node_modules/vite/dist/node/cli.js:863:7)

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @sveltejs/adapter-auto: ^6.0.0 => 6.1.0 
    @sveltejs/adapter-vercel: 5.9.0 => 5.9.0 
    @sveltejs/kit: ^2.22.0 => 2.30.1 
    @sveltejs/vite-plugin-svelte: ^6.0.0 => 6.1.2 
    svelte: ^5.25.0 => 5.38.1 
    vite: ^7.0.4 => 7.1.2

Severity

blocking an upgrade

Additional Information

No response

[jsilveira]

I can confirm the same issue. Downgrading to "@sveltejs/adapter-vercel": "5.8.2" fixed it

[konstantinblaesi]

for me kit versions are:

• good: 2.31.0
• bad: 2.30.1 (same error as above)

check if upgrading kit to this version or newer fixes it for you as well

looks like a fix was introduced