Fix retain cycles in ASDisplayNode and ASTableView

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -120,6 +120,7 @@
 		058D0A84195D060300B7D73C /* ASDisplayNodeExtraIvars.h in Headers */ = {isa = PBXBuildFile; fileRef = 058D0A45195D058D00B7D73C /* ASDisplayNodeExtraIvars.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		05A6D05A19D0EB64002DD95E /* ASDealloc2MainObject.h in Headers */ = {isa = PBXBuildFile; fileRef = 05A6D05819D0EB64002DD95E /* ASDealloc2MainObject.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		05A6D05B19D0EB64002DD95E /* ASDealloc2MainObject.m in Sources */ = {isa = PBXBuildFile; fileRef = 05A6D05919D0EB64002DD95E /* ASDealloc2MainObject.m */; settings = {COMPILER_FLAGS = "-fno-objc-arc"; }; };
+		3C9C128519E616EF00E942A0 /* ASTableViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 3C9C128419E616EF00E942A0 /* ASTableViewTests.m */; settings = {COMPILER_FLAGS = "-fno-objc-arc"; }; };
 		6BDC61F61979037800E50D21 /* AsyncDisplayKit.h in Headers */ = {isa = PBXBuildFile; fileRef = 6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		DB7121BCD50849C498C886FB /* libPods-AsyncDisplayKitTests.a in Frameworks */ = {isa = PBXBuildFile; fileRef = EFA731F0396842FF8AB635EE /* libPods-AsyncDisplayKitTests.a */; };
 /* End PBXBuildFile section */
@@ -238,6 +239,7 @@
 		058D0A45195D058D00B7D73C /* ASDisplayNodeExtraIvars.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASDisplayNodeExtraIvars.h; sourceTree = "<group>"; };
 		05A6D05819D0EB64002DD95E /* ASDealloc2MainObject.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASDealloc2MainObject.h; path = ../Details/ASDealloc2MainObject.h; sourceTree = "<group>"; };
 		05A6D05919D0EB64002DD95E /* ASDealloc2MainObject.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = ASDealloc2MainObject.m; path = ../Details/ASDealloc2MainObject.m; sourceTree = "<group>"; };
+		3C9C128419E616EF00E942A0 /* ASTableViewTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASTableViewTests.m; sourceTree = "<group>"; };
 		6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AsyncDisplayKit.h; sourceTree = "<group>"; };
 		EFA731F0396842FF8AB635EE /* libPods-AsyncDisplayKitTests.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-AsyncDisplayKitTests.a"; sourceTree = BUILT_PRODUCTS_DIR; };
 		FAD7085290B84183BD13BA1A /* Pods-AsyncDisplayKitTests.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-AsyncDisplayKitTests.xcconfig"; path = "Pods/Pods-AsyncDisplayKitTests.xcconfig"; sourceTree = "<group>"; };
@@ -344,6 +346,7 @@
 				058D0A30195D057000B7D73C /* ASDisplayNodeTestsHelper.h */,
 				058D0A31195D057000B7D73C /* ASDisplayNodeTestsHelper.m */,
 				058D0A32195D057000B7D73C /* ASMutableAttributedStringBuilderTests.m */,
+				3C9C128419E616EF00E942A0 /* ASTableViewTests.m */,
 				058D0A33195D057000B7D73C /* ASTextNodeCoreTextAdditionsTests.m */,
 				058D0A34195D057000B7D73C /* ASTextNodeRendererTests.m */,
 				058D0A35195D057000B7D73C /* ASTextNodeShadowerTests.m */,
@@ -688,6 +691,7 @@
 				058D0A39195D057000B7D73C /* ASDisplayNodeAppearanceTests.m in Sources */,
 				058D0A41195D057000B7D73C /* ASTextNodeWordKernerTests.mm in Sources */,
 				058D0A40195D057000B7D73C /* ASTextNodeTests.m in Sources */,
+				3C9C128519E616EF00E942A0 /* ASTableViewTests.m in Sources */,
 				058D0A38195D057000B7D73C /* ASDisplayLayerTests.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

AsyncDisplayKit/ASDisplayNode.h

@@ -236,7 +236,7 @@
 /** 
  * @abstract The receiver's supernode.
  */
-@property (nonatomic, readonly, assign) ASDisplayNode *supernode;
+@property (nonatomic, readonly, weak) ASDisplayNode *supernode;
 
 
 /** @name Drawing and Updating the View */

AsyncDisplayKit/ASTableView.m

@@ -47,8 +47,8 @@ static BOOL _isInterceptedSelector(SEL sel)
 @end
 
 @implementation _ASTableViewProxy {
-  id<NSObject> _target;
+  id<NSObject> __weak _target;
-  ASTableView *_interceptor;
+  ASTableView * __weak _interceptor;
 }
 
 - (instancetype)initWithTarget:(id<NSObject>)target interceptor:(ASTableView *)interceptor
@@ -140,7 +140,8 @@ static BOOL _isInterceptedSelector(SEL sel)
 
 - (void)setDelegate:(id<UITableViewDelegate>)delegate
 {
-  ASDisplayNodeAssert(NO, @"ASTableView uses asyncDelegate, not UITableView's delegate property.");
+  // Our UIScrollView superclass sets its delegate to nil on dealloc. Only assert if we get a non-nil value here.
+  ASDisplayNodeAssert(delegate == nil, @"ASTableView uses asyncDelegate, not UITableView's delegate property.");
 }
 
 - (void)setAsyncDataSource:(id<ASTableViewDataSource>)asyncDataSource

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -32,7 +32,7 @@ BOOL ASDisplayNodeSubclassOverridesSelector(Class subclass, SEL selector);
 @protected
   ASDN::RecursiveMutex _propertyLock;  // Protects access to the _view, _pendingViewState, _subnodes, _supernode, _renderingSubnodes, and other properties which are accessed from multiple threads.
 
-  ASDisplayNode *_supernode;
+  ASDisplayNode * __weak _supernode;
 
   ASSentinel *_displaySentinel;
   ASSentinel *_replaceAsyncSentinel;

AsyncDisplayKitTests/ASDisplayNodeTests.m

@@ -783,6 +783,32 @@ static inline BOOL _CGPointEqualToPointWithEpsilon(CGPoint point1, CGPoint point
   [v release];
 }
 
+- (void)testAddingSubnodeDoesNotCreateRetainCycle
+{
+  ASTestDisplayNode *node = [[ASTestDisplayNode alloc] init];
+
+  __block BOOL didDealloc = NO;
+  node.willDeallocBlock = ^(ASDisplayNode *n){
+    didDealloc = YES;
+  };
+
+  ASDisplayNode *subnode = [[ASDisplayNode alloc] init];
+
+  // verify initial
+  XCTAssertTrue(1 == node.retainCount, @"unexpected retain count:%tu", node.retainCount);
+  XCTAssertTrue(1 == subnode.retainCount, @"unexpected retain count:%tu", subnode.retainCount);
+
+  [node addSubnode:subnode];
+  XCTAssertTrue(2 == subnode.retainCount, @"node should retain subnode when added. retain count:%tu", node.retainCount);
+  XCTAssertTrue(1 == node.retainCount, @"subnode should not retain node when added. retain count:%tu", node.retainCount);
+
+  [subnode release];
+  XCTAssertTrue(1 == subnode.retainCount, @"subnode should be retained by node. retain count:%tu", subnode.retainCount);
+
+  [node release];
+  XCTAssertTrue(didDealloc, @"unexpected node lifetime:%@", node);
+}
+
 - (void)testMainThreadDealloc
 {
   __block BOOL didDealloc = NO;

AsyncDisplayKitTests/ASTableViewTests.m

@@ -0,0 +1,86 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <XCTest/XCTest.h>
+
+#import "ASTableView.h"
+
+@interface ASTestTableView : ASTableView
+@property (atomic, copy) void (^willDeallocBlock)(ASTableView *tableView);
+@end
+
+@implementation ASTestTableView
+
+- (void)dealloc
+{
+  if (_willDeallocBlock) {
+    _willDeallocBlock(self);
+  }
+  [super dealloc];
+}
+
+@end
+
+@interface ASTableViewTestDelegate : NSObject <ASTableViewDataSource, ASTableViewDelegate>
+@property (atomic, copy) void (^willDeallocBlock)(ASTableViewTestDelegate *delegate);
+@end
+
+@implementation ASTableViewTestDelegate
+
+- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
+{
+  return 0;
+}
+
+- (ASCellNode *)tableView:(ASTableView *)tableView nodeForRowAtIndexPath:(NSIndexPath *)indexPath
+{
+  return nil;
+}
+
+- (void)dealloc
+{
+  if (_willDeallocBlock) {
+    _willDeallocBlock(self);
+  }
+  [super dealloc];
+}
+
+@end
+
+@interface ASTableViewTests : XCTestCase
+@end
+
+@implementation ASTableViewTests
+
+- (void)testTableViewDoesNotRetainItselfAndDelegate
+{
+  ASTestTableView *tableView = [[ASTestTableView alloc] initWithFrame:CGRectZero style:UITableViewStylePlain];
+
+  __block BOOL tableViewDidDealloc = NO;
+  tableView.willDeallocBlock = ^(ASTableView *v){
+    tableViewDidDealloc = YES;
+  };
+
+  ASTableViewTestDelegate *delegate = [[ASTableViewTestDelegate alloc] init];
+
+  __block BOOL delegateDidDealloc = NO;
+  delegate.willDeallocBlock = ^(ASTableViewTestDelegate *d){
+    delegateDidDealloc = YES;
+  };
+
+  tableView.asyncDataSource = delegate;
+  tableView.asyncDelegate = delegate;
+
+  [delegate release];
+  XCTAssertTrue(delegateDidDealloc, @"unexpected delegate lifetime:%@", delegate);
+
+  XCTAssertNoThrow([tableView release], @"unexpected exception when deallocating table view:%@", tableView);
+  XCTAssertTrue(tableViewDidDealloc, @"unexpected table view lifetime:%@", tableView);
+}
+
+@end