From 6b44b5ac05adb8c776a1aed747291f8c80309d34 Mon Sep 17 00:00:00 2001
From: Adlai Holler <guy.on.internet@me.com>
Date: Mon, 11 Jul 2016 20:22:45 -0700
Subject: [PATCH] [ASTableView] Add retainedLayer a la collection view (#1896)

---
 AsyncDisplayKit/ASTableView.mm | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/AsyncDisplayKit/ASTableView.mm b/AsyncDisplayKit/ASTableView.mm
index 517554fb90..5e9f128b38 100644
--- a/AsyncDisplayKit/ASTableView.mm
+++ b/AsyncDisplayKit/ASTableView.mm
@@ -11,6 +11,7 @@
 #import "ASTableViewInternal.h"
 
 #import "ASAssert.h"
+#import "ASAvailability.h"
 #import "ASBatchFetching.h"
 #import "ASCellNode+Internal.h"
 #import "ASChangeSetDataController.h"
@@ -111,6 +112,15 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   CGFloat _contentOffsetAdjustment;
   
   CGPoint _deceleratingVelocity;
+  
+  /**
+   * Our layer, retained. Under iOS < 9, when table views are removed from the hierarchy,
+   * their layers may be deallocated and become dangling pointers. This puts the table view
+   * into a very dangerous state where pretty much any call will crash it. So we manually retain our layer.
+   *
+   * You should never access this, and it will be nil under iOS >= 9.
+   */
+  CALayer *_retainedLayer;
 
   CGFloat _nodesConstrainedWidth;
   BOOL _ignoreNodesConstrainedWidthChange;
@@ -235,6 +245,10 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
     self.strongTableNode = tableNode;
   }
   
+  if (!AS_AT_LEAST_IOS9) {
+    _retainedLayer = self.layer;
+  }
+  
   return self;
 }