Fix thread race in test-only XPC code. (#28041)
The clearRegistry block is touching various members of "self" that should only
be touched on self.workQueue. But it was being called on whatever queue the
client-provided stopReportsWithController method called its completion on.
The fix is to dispatch to the queue that getProxyHandleWithCompletion is passed,
which is in fact our work queue.
diff --git a/src/darwin/Framework/CHIP/MTRDeviceControllerXPCConnection.mm b/src/darwin/Framework/CHIP/MTRDeviceControllerXPCConnection.mm
index e443082..02f1e2c 100644
--- a/src/darwin/Framework/CHIP/MTRDeviceControllerXPCConnection.mm
+++ b/src/darwin/Framework/CHIP/MTRDeviceControllerXPCConnection.mm
@@ -170,9 +170,12 @@
[handle.proxy stopReportsWithController:controller
nodeId:nodeID.unsignedLongLongValue
completion:^{
+ // Make sure handle stays alive until we get to this
+ // completion (in particular while we are working
+ // with handle.proxy).
__auto_type handleRetainer = handle;
(void) handleRetainer;
- clearRegistry();
+ dispatch_async(queue, clearRegistry);
}];
} else {
MTR_LOG_ERROR("CHIP XPC connection failed to stop reporting");
