Michael Anthony Knyszek 54efef99b2 iter: deflake TestPull by letting exiting goroutines finish ... Currently TestPull is flaky because goroutines spawned to run subtests exit asynchronously when they finish and TestPull has explicit checks for the number of existing goroutines. This is pretty much only a problem between subtests executing, because within each subtest the coroutine goroutine spawned for iter.Pull always exits fully synchronously before the final `next` or `stop` returns. So, we can resolve the problem by ensuring the first goroutine count the test takes likely doesn't contain any exiting goroutines. The trick is to set GOMAXPROCS=1 and spin in runtime.Gosched until the number of goroutines stabilizes to some reasonable degree (we pick 100 consecutive iterations; there are only a handful of possible goroutines that can run, so this is giving that handful around 20 chances to actually run to completion). When running TestPull under stress2, this issue is easily reproducible before this CL. After this CL, it no longer reproduces under these conditions. Fixes #66017. Change-Id: I4bf0a9771f7364df7dd58f8aeb3ae26742d5746f Reviewed-on: https://go-review.googlesource.com/c/go/+/587917 Reviewed-by: David Chase <drchase@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>		2024-05-24 19:15:10 +00:00
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iter.go	iter: detect and reject double next and double yield in Pull, Pull2	2024-05-08 18:03:22 +00:00
pull_test.go	iter: deflake TestPull by letting exiting goroutines finish	2024-05-24 19:15:10 +00:00