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Purpose and Motivation
This PR fixes a data race that can happen when a
CondVar
is signaled immediately as it is timing out. The problem is easy to reproduce:An error is thrown because the time out mechanism is trying to wake a thread that has already been woken by the signal.
this.prRemoveWaitingThread(waitingThread);
returnsnil
in this case, sothis.prWakeThread(wokenThread);
throws an error having received anil
value.It doesn't look like this change has any adverse effects.
TestCondVar.sc
is still passing. I tried to write a test for this issue, but couldn't figure out a way to write one usingassertNoException
. If anyone knows how I can write a test for this, please let me know and I'll add it to this PR.Types of changes
To-do list