Add optional testing hook for blocking_concurrent_queue#59
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bghgary merged 3 commits intomicrosoft:masterfrom Apr 2, 2026
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Pull request overview
Adds a test-only hook to arcana::blocking_concurrent_queue to allow deterministic reproduction of lost-wakeup races by running a callback immediately before condition_variable::wait() while the queue mutex is held.
Changes:
- Introduces a global (test-only)
beforeWaitCallbackandset_before_wait_callback()setter behindARCANA_TESTING_HOOKS. - Invokes the callback right before
m_dataReady.wait(lock)in bothinternal_pop()andinternal_drain().
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ryantrem
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Apr 2, 2026
Add a global before-wait callback invoked while holding the queue mutex, right before condition_variable::wait(). This enables deterministic testing of lost-wakeup race conditions in code that uses the queue. Behind #ifdef ARCANA_TESTING_HOOKS -- zero cost when not enabled. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Add a global before-wait callback to blocking_concurrent_queue, invoked while holding the queue mutex right before condition_variable::wait().
Motivation
This enables deterministic testing of lost-wakeup race conditions. By sleeping in the callback (while holding the mutex), a test can guarantee a worker thread is between the condition check and wait(). Code that coordinates through push() (which acquires the mutex) will block until the worker enters wait() and deliver the notification correctly. Code that uses bare notify_all() (without the mutex) will lose the signal.
Changes
All behind ARCANA_TESTING_HOOKS -- zero cost when not enabled. No other files changed.
Usage
Used by BabylonJS/JsRuntimeHost#146 to deterministically reproduce a deadlock in AppRuntime shutdown.