Not resilient to modification of globals

[dubzzz]

The library does not resist destructive changes of the globals. As I initially reported the issue at vitest-dev/vitest#7024 I wanted to make you aware of the problem.

One fix, if you consider that it should be fixed, would be to capture the globals for Intl and Date when the code got imported.

Feel free to close, if the behavior is expected.

---

If the suggestion is relevant I can propose a fix.

[fatso83]

This is absolutely true and we have done similar changes in the main Sinon project to prevent pollution to globals (like methods on the Array.prototype) affecting us. If you want to supply a fix, it should just be a handful of lines.

[fatso83]

Meh, the run failed: https://github.com/sinonjs/fake-timers/actions/runs/12237218608/job/34132458756

452 passing (514ms)
  8 pending
  2 failing

  1) globally configured browser objects
       correctly instantiates and tears down:
     TypeError: Cannot set property navigator of #<Object> which has only a getter
      at setUpGlobal (integration-test/fake-clock-integration-test.js:7:[28](https://github.com/sinonjs/fake-timers/actions/runs/12237218608/job/34132458756#step:5:29)3)
      at Context.<anonymous> (integration-test/fake-clock-integration-test.js:7:1643)
      at process.processImmediate (node:internal/timers:491:21)

  2) globally configured browser objects
       correctly instantiates and tears down:
     Error: global leak(s) detected: 'window', 'document'
      at Runner.emit (node:events:5[30](https://github.com/sinonjs/fake-timers/actions/runs/12237218608/job/34132458756#step:5:31):35)
      at process.processImmediate (node:internal/timers:491:21)

[dubzzz]

Arf strange! Sorry for the inconvenience, I'll have to rework it

[dubzzz]

Please feel free to revert in case it's blocking you. I'll try to do my best to have something soon

[fatso83]

So weird. Works locally:

 npx mocha --timeout 200 test/ integration-test/  -R dot --check-leaks

[fatso83]

Ah, works in Node 20. Fails in Node 22.12.0

[fatso83]

Sorry, this is not on you. This is from #515 #518

[fatso83]

I did not notice this had failed on merge: https://github.com/sinonjs/fake-timers/commits/main/

[fatso83]

Found the issue: #518

Sorry for the noise!