Calling sinon.useFakeTimers() inside a test causes Vitest to hang

Describe the bug

Calling sinon.useFakeTimers() in a test causes the test to hang:

> test
> vitest


 DEV  v3.1.1 /Users/josh/repos/repros


 ❯ index.test.js 0/1

 Test Files 0 passed (1)
      Tests 0 passed (1)
   Start at 09:26:11
   Duration 12.34s

After a minute it exits with an error:

 DEV  v3.1.1 /Users/josh/repos/repros

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Unhandled Errors ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

Vitest caught 1 unhandled error during the test run.
This might cause false positive tests. Resolve unhandled errors to make sure your tests are not affected.

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Unhandled Error ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
Error: [vitest-worker]: Timeout calling "snapshotSaved"
 ❯ Object.onTimeoutError node_modules/vitest/dist/chunks/rpc.DGgL5dw7.js:62:10
 ❯ Timeout._onTimeout node_modules/vitest/dist/chunks/index.68735LiX.js:55:41
 ❯ listOnTimeout node:internal/timers:594:17
 ❯ processTimers node:internal/timers:529:7

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯


 Test Files   (1)
      Tests   (1)
     Errors  1 error
   Start at  09:27:40
   Duration  60.19s (transform 11ms, setup 0ms, collect 17ms, tests 0ms, environment 0ms, prepare 36ms)

Reproduction

Minimum reproduction: https://github.com/JoshuaKGoldberg/repros/tree/vitest-hanging-with-sinon-useFakeTimers

The full use case is a package that wraps a Sinon API: https://github.com/JoshuaKGoldberg/sinon-timers-repeatable/pull/894

System Info

System:
    OS: macOS 13.2
    CPU: (10) arm64 Apple M1 Max
    Memory: 132.53 MB / 32.00 GB
    Shell: 5.8.1 - /bin/zsh
  Binaries:
    Node: 22.12.0 - ~/.nvm/versions/node/v22.12.0/bin/node
    Yarn: 1.22.19 - ~/.yarn/bin/yarn
    npm: 10.9.0 - ~/.nvm/versions/node/v22.12.0/bin/npm
    pnpm: 10.6.1 - ~/.nvm/versions/node/v22.12.0/bin/pnpm
  Browsers:
    Chrome: 134.0.6998.166
    Safari: 16.3
  npmPackages:
    vitest: ^3.1.1 => 3.1.1

Used Package Manager

npm

Validations

• Follow our Code of Conduct
• 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.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

Start by running the minimal reproduction from the linked vitest-hanging-with-sinon-useFakeTimers repository with Vitest 3.1.1 and sinon.useFakeTimers(). Trace the worker RPC path around the reported snapshotSaved timeout, then add a regression test showing the test run completes without hanging or timing out.