@vitest/mocker 4.1.0: vite declared as optional peer dependency but imported unconditionally in dist/node.js

[PersaPaul]

Describe the bug

Starting with @vitest/mocker 4.1.0, running vitest with @vitest/browser-playwright fails with ERR_MODULE_NOT_FOUND if vite is not explicitly installed in the project, even though vite is declared as an optional peer dependency.

Expected: Tests run (or a graceful error if vite is required)

Actual:

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'vite' imported from /path/to/node_modules/@vitest/browser-playwright/node_modules/@vitest/mocker/dist/node.js

Root cause

In @vitest/mocker/package.json, vite is declared as optional:

"peerDependencies": {
  "vite": "^6.0.0 || ^7.0.0 || ^8.0.0-0"
},
"peerDependenciesMeta": {
  "vite": {
    "optional": true
  }
}

However, dist/node.js appears to have an unconditional static import of vite, causing Node.js module resolution to fail immediately at load time when vite is not present.

This worked in 4.0.18

Workaround

Explicitly install vite as a devDependency:

npm install vite --save-dev

Reproduction

https://stackblitz.com/edit/vitest-dev-vitest-bjtmmvai?file=package.json&initialPath=__vitest__/

1. Create a project with the following devDependencies:

   {
     "devDependencies": {
       "@vitest/browser-playwright": "4.1.0",
       "vitest": "4.1.0"
     }
   }

2. Run npm install
3. Run vitest

System Info

System:
    OS: macOS 26.3.1
    CPU: (12) arm64 Apple M4 Pro
    Memory: 8.55 GB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.22.1 - /usr/local/bin/node
    npm: 10.9.4 - /usr/local/bin/npm
  Browsers:
    Chrome: 146.0.7680.153
    Safari: 26.3.1
  npmPackages:
    @vitest/browser-playwright: 4.1 => 4.1.0 
    vitest: 4.1 => 4.1.0

Used Package Manager

npm

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
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• The provided reproduction is a minimal reproducible example of the bug.

[github-actions]

Hello @PersaPaul. Please provide a minimal reproduction using a GitHub repository or StackBlitz (you can also use examples). Issues marked with needs reproduction will be closed if they have no activity within 3 days.

[sheremet-va]

Mocker package always had vite as optional because there are entry points that don't require vite. Vitest requires vite, @vitest/browser-playwright requires vitest, so vite will always be available to @vitest/mocker.

You reproduction works properly even after adding @vitest/browser-playwright to the config.