regression: versions 2.63.0 and above break vitest global setup

[MaddyGuthridge]

Describe the bug

When I attempt to update @sveltejs/kit, my CI fails, with the following error:

ReferenceError: __SVELTEKIT_APP_VERSION__ is not defined

This specifically occurs when I import { browser } from '$app/environment'; inside of a globalSetup test file. It appears that accessing $app/environment in any way during global setup causes this error.

Version 2.62.0 does not encounter this issue, but versions 2.63 and above all cause it.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-fann5ee8?file=tests%2FglobalSetup.ts

• npm ci
• npm t

Logs

$ npm t
> minifolio@1.4.0 test
> vitest run


 RUN  v4.1.9 /home/maddy/Source/sveltekit-vitest-repro

No test files found, exiting with code 1

include: **/*.{test,spec}.?(c|m)[jt]s?(x)
exclude:  **/node_modules/**, **/.git/**


⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Unhandled Error ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
ReferenceError: __SVELTEKIT_APP_VERSION__ is not defined
 ❯ node_modules/@sveltejs/kit/src/runtime/app/env/internal.js?v=7391b49e:1:24
 ❯ VitestModuleEvaluator._runInlinedModule node_modules/vitest/dist/module-evaluator.js:206:120
 ❯ node_modules/vitest/dist/module-evaluator.js:107:62
 ❯ Traces.$ node_modules/vitest/dist/chunks/traces.DT5aQ62U.js:142:27
 ❯ VitestModuleEvaluator.runInlinedModule node_modules/vitest/dist/module-evaluator.js:107:21
 ❯ ServerModuleRunner.directRequest node_modules/vite/dist/node/module-runner.js:1259:80
 ❯ ServerModuleRunner.cachedRequest node_modules/vite/dist/node/module-runner.js:1166:73

System Info

System:
    OS: Linux 7.1 cpe:/o:nixos:nixos:26.05 26.05 (Yarara)
    CPU: (12) x64 Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz
    Memory: 46.77 GB / 62.43 GB
    Container: Yes
    Shell: 5.9.1 - /run/current-system/sw/bin/zsh
  Binaries:
    Node: 24.18.0 - /home/maddy/.local/share/mise/installs/node/24/bin/node
    npm: 11.16.0 - /home/maddy/.local/share/mise/installs/node/24/bin/npm
    pnpm: 11.9.0 - /home/maddy/.local/share/mise/installs/github-pnpm-pnpm/latest/pnpm
    bun: 1.3.14 - /home/maddy/.local/share/mise/installs/bun/latest/bin/bun
    Deno: 2.9.0 - /home/maddy/.local/share/mise/installs/deno/2.9.0/bin/deno
  Browsers:
    Chromium: 149.0.7827.200
    Firefox: 152.0.3
    Firefox Developer Edition: 152.0.3
  npmPackages:
    @sveltejs/adapter-node: ^5.5.7 => 5.5.7 
    @sveltejs/kit: ^2.63.0 => 2.63.0 
    @sveltejs/vite-plugin-svelte: ^7.1.2 => 7.1.2 
    svelte: ^5.56.4 => 5.56.4 
    vite: ^8.1.0 => 8.1.0

Severity

blocking an upgrade

Additional Information

No response

[elliott-with-the-longest-name-on-github]

So this happens because __SVELTEKIT_APP_VERSION__ is statically replaced using define in our Vite configuration. Vitest, in its infinite wisdom, specifically removes those defines in their Vite plugin. I... honestly don't know how to fix that.

[elliott-with-the-longest-name-on-github]

Further information:

It looks like Vitest removes all define entries, then adds them to globalThis during tests, but only during tests -- so they're completely unavailable to anything that runs outside of a test runner. I have no idea why they decided to do this.

[MaddyGuthridge]

Worth reporting as a bug in vitest as well then? This is very much an issue in sveltekit too, given this didn't happen until 2.63.0 (even if it isn't our fault), so I'll keep this issue open.

[MaddyGuthridge]

Thanks so much! When can I expect this to be released?

[Rich-Harris]

Just released 2.69.2 with the fix!