fake clock: expose the number of waiters #325
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/assign @dims cross referencing kubernetes/kubernetes@c805d32#r2070948260 |
danwinship
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May 2, 2025
By using `Waiters()`, tests can wait until the expected number of waiters are present before manipulating the clock's time, ensuring that the goroutine under test has reached a stable state regarding its timers. Change-Id: I64d7b89f5e178a72898885642818215e8ad73a9d
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/approve thanks for the review @danwinship |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: aojea, dims The full list of commands accepted by this bot can be found here. The pull request process is described here
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By using
Waiters(), tests can wait until the expected number of waiters are present before manipulating the clock's time, ensuring that the goroutine under test has reached a stable state regarding its timers./kind feature
/kind flake
What this PR does / why we need it:
When working on kubernetes/kubernetes#131502 it took me a while to find the source of flakiness, the code under test uses two timers and runs in a goroutinge.
There is a race between the test code when updating the fake clock time, that may happen before the timers are reset.
The fake clock already has the
HasWaiters()method, but that only works for one timer, leaving a small window for the race to happen. In order to avoid that, we need to expose the actual number of waiters to be able to synchronize the test .Release note:
/assign @thockin @danwinship