fix(clock): reset ticks on first install to avoid realTime drift#40198
Merged
dgozman merged 1 commit intomicrosoft:mainfrom Apr 14, 2026
Merged
fix(clock): reset ticks on first install to avoid realTime drift#40198dgozman merged 1 commit intomicrosoft:mainfrom
dgozman merged 1 commit intomicrosoft:mainfrom
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Between `inject()` (which starts the realTime ticker) and the user's `install(time)` call, `_now.ticks` accumulates drift. Since `performance.now()` returns `ticks`, this drift leaked into `performance.now()` values observed by the page. Reset `ticks` to 0 on the first `install()` (when origin has not been set yet) so the monotonic counter starts from a pristine state. Exposed by the flaky test `library/page-clock.spec.ts:282 replaces global performance.timeOrigin` on Firefox.
pavelfeldman
approved these changes
Apr 14, 2026
Contributor
Test results for "tests 1"1 failed 3 flaky39179 passed, 847 skipped Merge workflow run. |
Contributor
Test results for "MCP"5974 passed, 916 skipped Merge workflow run. |
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Summary
inject()(which starts the realTime ticker) and the user'sinstall(time)call,_now.ticksaccumulates drift. Sinceperformance.now()returnsticks, that drift leaked into values the page observed.ticksto 0 on the firstinstall()(when origin hasn't been set yet) so the monotonic counter starts from a pristine state.library/page-clock.spec.ts:282 replaces global performance.timeOriginon Firefox.