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Investigate flaky WaitFor* timeouts on CI - #1952
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🟡 Changes recommended
Timer-initialization failures can leave callers waiting indefinitely, and the scheduling changes need regression coverage.
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What changed in this PR
Adds diagnostics and scheduling changes to investigate flaky bUnit WaitFor* timeouts on CI.
Changes:
- Logs elapsed time and thread-pool statistics on timeout.
- Defers timer startup and coordinates it with disposal.
- Raises test thread-pool minimums and initializes element-count state earlier.
| File | Description |
|---|---|
| tests/bunit.tests/Assembly.cs | Raises minimum worker threads for tests. |
| src/bunit/Extensions/WaitForHelpers/WaitForHelperLoggerExtensions.cs | Expands timeout diagnostics. |
| src/bunit/Extensions/WaitForHelpers/WaitForHelper.cs | Moves timer startup into dispatcher initialization and synchronizes disposal. |
| src/bunit/Extensions/WaitForHelpers/WaitForElementsHelper.cs | Uses a primary constructor to capture element count before base initialization. |
Review effort: Balanced
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| lock (checkPassedCompletionSource) | ||
| { | ||
| if (isDisposed || WaitTask.IsCompleted) | ||
| return; |
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| dispatcherEntered.Wait(Xunit.TestContext.Current.CancellationToken); | ||
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| var waitTask = cut.WaitForElementAsync("#notHere", TimeSpan.FromMilliseconds(5)); | ||
| await Task.Delay(50, Xunit.TestContext.Current.CancellationToken); | ||
| releaseDispatcher.Set(); | ||
| await blocker; |
- Start the WaitFor timeout timer only after the initial check ran on the renderer dispatcher; previously a busy dispatcher let the timer expire before any check executed. - Capture matchElementCount in WaitForElementsHelper before the base constructor starts the timer, which reads TimeoutErrorMessage. - Raise the thread pool floor in Bunit.Tests: parallel tests blocking pool threads starved the continuations they waited on. - Log configured vs actual elapsed time and thread pool load on timeout.
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Diagnostics for sporadic WaitFor* timeouts (e.g. runs 39277565989, 39276248124). Logs thread pool stats and actual vs configured elapsed time when a waiter times out.