[Matter.framework] Prevent a leak when using the _subscriptionPoolWor… (project-chip#35978)

Author: vivien-apple

src/darwin/Framework/CHIP/MTRDevice_Concrete.mm

@@ -757,7 +757,9 @@ - (void)_ensureSubscriptionForExistingDelegates:(NSString *)reason
         }
         if ([self _deviceUsesThread]) {
             MTR_LOG(" => %@ - device is a thread device, scheduling in pool", self);
+            mtr_weakify(self);
             [self _scheduleSubscriptionPoolWork:^{
+                mtr_strongify(self);
                 [self->_deviceController asyncDispatchToMatterQueue:^{
                     std::lock_guard lock(self->_lock);
                     [self _setupSubscriptionWithReason:[NSString stringWithFormat:@"%@ and scheduled subscription is happening", reason]];
@@ -1165,10 +1167,13 @@ - (void)_scheduleSubscriptionPoolWork:(dispatch_block_t)workBlock inNanoseconds:
         return;
     }
 
+    mtr_weakify(self);
     dispatch_block_t workBlockToQueue = ^{
+        mtr_strongify(self);
         // In the case where a resubscription triggering event happened and already established, running the work block should result in a no-op
         MTRAsyncWorkItem * workItem = [[MTRAsyncWorkItem alloc] initWithQueue:self.queue];
         [workItem setReadyHandler:^(id _Nonnull context, NSInteger retryCount, MTRAsyncWorkCompletionBlock _Nonnull completion) {
+            mtr_strongify(self);
             MTR_LOG("%@ - work item is ready to attempt pooled subscription", self);
             os_unfair_lock_lock(&self->_lock);
 #ifdef DEBUG
@@ -1246,7 +1251,9 @@ - (void)_handleResubscriptionNeededWithDelayOnDeviceQueue:(NSNumber *)resubscrip
 
     // Use the existing _triggerResubscribeWithReason mechanism, which does the right checks when
     // this block is run -- if other triggering events had happened, this would become a no-op.
+    mtr_weakify(self);
     auto resubscriptionBlock = ^{
+        mtr_strongify(self);
         [self->_deviceController asyncDispatchToMatterQueue:^{
             [self _triggerResubscribeWithReason:@"ResubscriptionNeeded timer fired" nodeLikelyReachable:NO];
         } errorHandler:^(NSError * _Nonnull error) {
@@ -1357,7 +1364,9 @@ - (void)_doHandleSubscriptionReset:(NSNumber * _Nullable)retryDelay
 
     // Call _reattemptSubscriptionNowIfNeededWithReason when timer fires - if subscription is
     // in a better state at that time this will be a no-op.
+    mtr_weakify(self);
     auto resubscriptionBlock = ^{
+        mtr_strongify(self);
         [self->_deviceController asyncDispatchToMatterQueue:^{
             std::lock_guard lock(self->_lock);
             [self _reattemptSubscriptionNowIfNeededWithReason:@"got subscription reset"];