[ASTableView / ASCollectionView] Support running without an asyncDelegate set.

AsyncDisplayKit/ASCollectionView.mm

@@ -242,6 +242,12 @@ - (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionVi
 
   _registeredSupplementaryKinds = [NSMutableSet set];
 
+  _proxyDelegate = [[_ASCollectionViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
+  super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
+
+  _proxyDataSource = [[_ASCollectionViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
+  super.dataSource = (id<UICollectionViewDataSource>)_proxyDataSource;
+
   self.backgroundColor = [UIColor whiteColor];
 
   [self registerClass:[_ASCollectionViewCell class] forCellWithReuseIdentifier:kCellReuseIdentifier];
@@ -253,6 +259,8 @@ - (void)dealloc
 {
   // Sometimes the UIKit classes can call back to their delegate even during deallocation.
   // This bug might be iOS 7-specific.
+  _proxyDelegate = nil;
+  _proxyDataSource = nil;
   super.delegate  = nil;
   super.dataSource = nil;
 }
@@ -315,17 +323,19 @@ - (void)setAsyncDataSource:(id<ASCollectionViewDataSource>)asyncDataSource
   // will return as nil (ARC magic) even though the _proxyDataSource still exists. It's really important to nil out
   // super.dataSource in this case because calls to _ASTableViewProxy will start failing and cause crashes.
 
+  super.dataSource = nil;
+
   if (asyncDataSource == nil) {
-    super.dataSource = nil;
     _asyncDataSource = nil;
-    _proxyDataSource = nil;
+    _proxyDataSource = [[_ASCollectionViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
     _asyncDataSourceImplementsConstrainedSizeForNode = NO;
   } else {
     _asyncDataSource = asyncDataSource;
     _proxyDataSource = [[_ASCollectionViewProxy alloc] initWithTarget:_asyncDataSource interceptor:self];
-    super.dataSource = (id<UICollectionViewDataSource>)_proxyDataSource;
     _asyncDataSourceImplementsConstrainedSizeForNode = ([_asyncDataSource respondsToSelector:@selector(collectionView:constrainedSizeForNodeAtIndexPath:)] ? 1 : 0);
   }
+
+  super.dataSource = (id<UICollectionViewDataSource>)_proxyDataSource;
 }
 
 - (void)setAsyncDelegate:(id<ASCollectionViewDelegate>)asyncDelegate
@@ -335,19 +345,21 @@ - (void)setAsyncDelegate:(id<ASCollectionViewDelegate>)asyncDelegate
   // will return as nil (ARC magic) even though the _proxyDelegate still exists. It's really important to nil out
   // super.delegate in this case because calls to _ASTableViewProxy will start failing and cause crashes.
 
+  super.delegate = nil;
+
   if (asyncDelegate == nil) {
     // order is important here, the delegate must be callable while nilling super.delegate to avoid random crashes
     // in UIScrollViewAccessibility.
-    super.delegate = nil;
     _asyncDelegate = nil;
-    _proxyDelegate = nil;
+    _proxyDelegate = [[_ASCollectionViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
     _asyncDelegateImplementsInsetSection = NO;
   } else {
     _asyncDelegate = asyncDelegate;
     _proxyDelegate = [[_ASCollectionViewProxy alloc] initWithTarget:_asyncDelegate interceptor:self];
-    super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
     _asyncDelegateImplementsInsetSection = ([_asyncDelegate respondsToSelector:@selector(collectionView:layout:insetForSectionAtIndex:)] ? 1 : 0);
   }
+
+  super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
 
   [_layoutInspector didChangeCollectionViewDelegate:asyncDelegate];
 }

AsyncDisplayKit/ASTableView.mm

@@ -224,6 +224,12 @@ - (void)configureWithDataControllerClass:(Class)dataControllerClass asyncDataFet
   // If the initial size is 0, expect a size change very soon which is part of the initial configuration
   // and should not trigger a relayout.
   _ignoreNodesConstrainedWidthChange = (_nodesConstrainedWidth == 0);
+
+  _proxyDelegate = [[_ASTableViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
+  super.delegate = (id<UITableViewDelegate>)_proxyDelegate;
+
+  _proxyDataSource = [[_ASTableViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
+  super.dataSource = (id<UITableViewDataSource>)_proxyDataSource;
 
   [self registerClass:_ASTableViewCell.class forCellReuseIdentifier:kCellReuseIdentifier];
 }
@@ -266,6 +272,8 @@ - (void)dealloc
 {
   // Sometimes the UIKit classes can call back to their delegate even during deallocation.
   // This bug might be iOS 7-specific.
+  _proxyDelegate = nil;
+  _proxyDataSource = nil;
   super.delegate  = nil;
   super.dataSource = nil;
 }
@@ -292,15 +300,17 @@ - (void)setAsyncDataSource:(id<ASTableViewDataSource>)asyncDataSource
   // will return as nil (ARC magic) even though the _proxyDataSource still exists. It's really important to nil out
   // super.dataSource in this case because calls to _ASTableViewProxy will start failing and cause crashes.
 
+  super.dataSource = nil;
+
   if (asyncDataSource == nil) {
-    super.dataSource = nil;
     _asyncDataSource = nil;
-    _proxyDataSource = nil;
+    _proxyDataSource = [[_ASTableViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
   } else {
     _asyncDataSource = asyncDataSource;
     _proxyDataSource = [[_ASTableViewProxy alloc] initWithTarget:_asyncDataSource interceptor:self];
-    super.dataSource = (id<UITableViewDataSource>)_proxyDataSource;
   }
+
+  super.dataSource = (id<UITableViewDataSource>)_proxyDataSource;
 }
 
 - (void)setAsyncDelegate:(id<ASTableViewDelegate>)asyncDelegate
@@ -310,17 +320,19 @@ - (void)setAsyncDelegate:(id<ASTableViewDelegate>)asyncDelegate
   // will return as nil (ARC magic) even though the _proxyDelegate still exists. It's really important to nil out
   // super.delegate in this case because calls to _ASTableViewProxy will start failing and cause crashes.
 
+  super.delegate = nil;
+
   if (asyncDelegate == nil) {
     // order is important here, the delegate must be callable while nilling super.delegate to avoid random crashes
     // in UIScrollViewAccessibility.
-    super.delegate = nil;
     _asyncDelegate = nil;
-    _proxyDelegate = nil; 
+    _proxyDelegate = [[_ASTableViewProxy alloc] initWithTarget:[NSNull null] interceptor:self];
   } else {
     _asyncDelegate = asyncDelegate;
     _proxyDelegate = [[_ASTableViewProxy alloc] initWithTarget:asyncDelegate interceptor:self];
-    super.delegate = (id<UITableViewDelegate>)_proxyDelegate;
   }
+
+  super.delegate = (id<UITableViewDelegate>)_proxyDelegate;
 }
 
 - (void)reloadDataWithCompletion:(void (^)())completion