Import from $app/navigation results in undefined property error

[ThomasBoom89]

Describe the bug

I did an upgrade of @sveltejs/kit to version 2.27.2 and now the import statement of my vitest crashes.

This statement -> import * as models from '$app/navigation';
leads to this when running vitest:

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Suites 1 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

 FAIL  src/import.test.ts [ src/import.test.ts ]
TypeError: Cannot read properties of undefined (reading 'data')
 ❯ node_modules/@sveltejs/kit/src/runtime/client/client.js:181:55
    179| 
    180| /** @type {Record<string, any>} */
    181| export const remote_responses = __SVELTEKIT_PAYLOAD__.data ?? {};
       |                                                       ^
    182| 
    183| /** @type {Array<((url: URL) => boolean)>} */
 ❯ node_modules/@sveltejs/kit/src/runtime/app/navigation.js:1:1

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯

Reproduction

I can reproduce it with a fresh project here.

import { test, vi } from 'vitest';
import * as models from '$app/navigation';

test('test', async () => {
  vi.spyOn(models, 'goto').mockImplementation((): Promise<void> => {
    return new Promise<void>((resolve) => {
      resolve();
    });
  });
});

Logs

System Info

System:
    OS: Linux 6.15 Arch Linux
    CPU: (32) x64 AMD Ryzen 9 7950X3D 16-Core Processor
    Memory: 44.49 GB / 62.01 GB
    Container: Yes
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.18.0 - ~/.nvm/versions/node/v22.18.0/bin/node
    npm: 10.9.3 - ~/.nvm/versions/node/v22.18.0/bin/npm
  Browsers:
    Chromium: 138.0.7204.168
  npmPackages:
    @sveltejs/adapter-auto: ^6.0.0 => 6.0.1 
    @sveltejs/kit: 2.27.2 => 2.27.2 
    @sveltejs/vite-plugin-svelte: ^6.0.0 => 6.1.0 
    svelte: ^5.0.0 => 5.38.0 
    vite: ^7.0.4 => 7.1.0

Severity

serious, but I can work around it

Additional Information

The workaround is to use version 2.27.1

I think this commit leads to the problem.

[damien-leakmited]

Same here ✋

[LucasHillDex]

Same issue with unit tests that have components that import from: $app/forms

[thebjorn]

Also present in 2.27.3