From 9762e7cfe64febc4a2450de65c9c5b37aee8c88e Mon Sep 17 00:00:00 2001
From: Ethan Nagel <eanagel@gmail.com>
Date: Thu, 16 Jul 2015 20:26:28 -0700
Subject: [PATCH] short-circuit editing calls after the asyncDataSource has
 been set to nil (ASTableView)

---
 AsyncDisplayKit/ASTableView.mm | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/AsyncDisplayKit/ASTableView.mm b/AsyncDisplayKit/ASTableView.mm
index b5ff1fb48f..bfaded25ab 100644
--- a/AsyncDisplayKit/ASTableView.mm
+++ b/AsyncDisplayKit/ASTableView.mm
@@ -499,12 +499,25 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
 - (void)rangeControllerBeginUpdates:(ASRangeController *)rangeController
 {
   ASDisplayNodeAssertMainThread();
+
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   [super beginUpdates];
 }
 
 - (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 endUpdates];
 
   if (completion) {
@@ -577,6 +590,10 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   BOOL preventAnimation = animationOptions == UITableViewRowAnimationNone;
   ASPerformBlockWithoutAnimation(preventAnimation, ^{
     [super insertRowsAtIndexPaths:indexPaths withRowAnimation:(UITableViewRowAnimation)animationOptions];
@@ -587,6 +604,10 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   BOOL preventAnimation = animationOptions == UITableViewRowAnimationNone;
   ASPerformBlockWithoutAnimation(preventAnimation, ^{
     [super deleteRowsAtIndexPaths:indexPaths withRowAnimation:(UITableViewRowAnimation)animationOptions];
@@ -597,6 +618,10 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   BOOL preventAnimation = animationOptions == UITableViewRowAnimationNone;
   ASPerformBlockWithoutAnimation(preventAnimation, ^{
     [super insertSections:indexSet withRowAnimation:(UITableViewRowAnimation)animationOptions];
@@ -607,6 +632,10 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
 {
   ASDisplayNodeAssertMainThread();
 
+  if (!self.asyncDataSource) {
+    return; // if the asyncDataSource has become invalid while we are processing, ignore this request to avoid crashes
+  }
+
   BOOL preventAnimation = animationOptions == UITableViewRowAnimationNone;
   ASPerformBlockWithoutAnimation(preventAnimation, ^{
     [super deleteSections:indexSet withRowAnimation:(UITableViewRowAnimation)animationOptions];