From c14ecd7e99719775e27109e9dfa96b799ec7fa06 Mon Sep 17 00:00:00 2001
From: Ethan Nagel <eanagel@gmail.com>
Date: Thu, 16 Jul 2015 20:26:45 -0700
Subject: [PATCH] short-circuit editing calls after the asyncDataSource has
 been set to nil (ASCollectionView)

---
 AsyncDisplayKit/ASCollectionView.mm | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/AsyncDisplayKit/ASCollectionView.mm b/AsyncDisplayKit/ASCollectionView.mm
index 36a995f90b..ee9648cdc7 100644
--- a/AsyncDisplayKit/ASCollectionView.mm
+++ b/AsyncDisplayKit/ASCollectionView.mm
@@ -543,6 +543,13 @@ static BOOL _isInterceptedSelector(SEL sel)
 - (void)rangeControllerEndUpdates:(ASRangeController *)rangeController completion:(void (^)(BOOL))completion {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    if (completion) {
+      completion(NO);
+    }
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   [super performBatchUpdates:^{
     [_batchUpdateBlocks enumerateObjectsUsingBlock:^(dispatch_block_t block, NSUInteger idx, BOOL *stop) {
       block();
@@ -577,6 +584,11 @@ static BOOL _isInterceptedSelector(SEL sel)
 - (void)rangeController:(ASRangeController *)rangeController didInsertNodesAtIndexPaths:(NSArray *)indexPaths withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions
 {
   ASDisplayNodeAssertMainThread();
+
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   if (_performingBatchUpdates) {
     [_batchUpdateBlocks addObject:^{
       [super insertItemsAtIndexPaths:indexPaths];
@@ -592,6 +604,10 @@ static BOOL _isInterceptedSelector(SEL sel)
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   if (_performingBatchUpdates) {
     [_batchUpdateBlocks addObject:^{
       [super deleteItemsAtIndexPaths:indexPaths];
@@ -607,6 +623,10 @@ static BOOL _isInterceptedSelector(SEL sel)
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   if (_performingBatchUpdates) {
     [_batchUpdateBlocks addObject:^{
       [super insertSections:indexSet];
@@ -622,6 +642,10 @@ static BOOL _isInterceptedSelector(SEL sel)
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   if (_performingBatchUpdates) {
     [_batchUpdateBlocks addObject:^{
       [super deleteSections:indexSet];