[_ASPendingState] Make sure accessibility strings are not nil before allocating attributed strings for them #trivial

Source/Private/ASDisplayNode+UIViewBridge.mm

@@ -943,7 +943,7 @@ - (void)setAccessibilityLabel:(NSString *)accessibilityLabel
   _bridge_prologue_write;
   _setAccessibilityToViewAndProperty(_accessibilityLabel, accessibilityLabel, accessibilityLabel, accessibilityLabel);
   if (AS_AT_LEAST_IOS11) {
-    NSAttributedString *accessibilityAttributedLabel = [[NSAttributedString alloc] initWithString:accessibilityLabel];
+    NSAttributedString *accessibilityAttributedLabel = accessibilityLabel ? [[NSAttributedString alloc] initWithString:accessibilityLabel] : nil;
     _setAttributedAccessibilityToViewAndProperty(_accessibilityAttributedLabel, accessibilityAttributedLabel, @"accessibilityAttributedLabel", accessibilityAttributedLabel);
   }
 }
@@ -972,7 +972,7 @@ - (void)setAccessibilityHint:(NSString *)accessibilityHint
   _bridge_prologue_write;
   _setAccessibilityToViewAndProperty(_accessibilityHint, accessibilityHint, accessibilityHint, accessibilityHint);
   if (AS_AT_LEAST_IOS11) {
-    NSAttributedString *accessibilityAttributedHint = [[NSAttributedString alloc] initWithString:accessibilityHint];
+    NSAttributedString *accessibilityAttributedHint = accessibilityHint ? [[NSAttributedString alloc] initWithString:accessibilityHint] : nil;
     _setAttributedAccessibilityToViewAndProperty(_accessibilityAttributedHint, accessibilityAttributedHint, @"accessibilityAttributedHint", accessibilityAttributedHint);
   }
 }
@@ -1001,7 +1001,7 @@ - (void)setAccessibilityValue:(NSString *)accessibilityValue
   _bridge_prologue_write;
   _setAccessibilityToViewAndProperty(_accessibilityValue, accessibilityValue, accessibilityValue, accessibilityValue);
   if (AS_AT_LEAST_IOS11) {
-    NSAttributedString *accessibilityAttributedValue = [[NSAttributedString alloc] initWithString:accessibilityValue];
+    NSAttributedString *accessibilityAttributedValue = accessibilityValue ? [[NSAttributedString alloc] initWithString:accessibilityValue] : nil;
     _setAttributedAccessibilityToViewAndProperty(_accessibilityAttributedValue, accessibilityAttributedValue, @"accessibilityAttributedValue", accessibilityAttributedValue);
   }
 }

Source/Private/_ASPendingState.mm

@@ -20,8 +20,9 @@
 #import <AsyncDisplayKit/_ASCoreAnimationExtras.h>
 #import <AsyncDisplayKit/_ASAsyncTransactionContainer.h>
 #import <AsyncDisplayKit/ASAssert.h>
-#import <AsyncDisplayKit/ASInternalHelpers.h>
+#import <AsyncDisplayKit/ASEqualityHelpers.h>
 #import <AsyncDisplayKit/ASDisplayNodeInternal.h>
+#import <AsyncDisplayKit/ASInternalHelpers.h>
 
 #define __shouldSetNeedsDisplay(layer) (flags.needsDisplay \
   || (flags.setOpaque && opaque != (layer).opaque)\
@@ -595,11 +596,11 @@ - (NSString *)accessibilityLabel
 
 - (void)setAccessibilityLabel:(NSString *)newAccessibilityLabel
 {
-  if (![accessibilityLabel isEqualToString:newAccessibilityLabel]) {
+  if (! ASObjectIsEqual(accessibilityLabel, newAccessibilityLabel)) {
     _flags.setAccessibilityLabel = YES;
     _flags.setAccessibilityAttributedLabel = YES;
-    accessibilityLabel = [newAccessibilityLabel copy];
-    accessibilityAttributedLabel = [[NSAttributedString alloc] initWithString:newAccessibilityLabel];
+    accessibilityLabel = newAccessibilityLabel ? [newAccessibilityLabel copy] : nil;
+    accessibilityAttributedLabel = newAccessibilityLabel ? [[NSAttributedString alloc] initWithString:newAccessibilityLabel] : nil;
   }
 }
 
@@ -610,11 +611,11 @@ - (NSAttributedString *)accessibilityAttributedLabel
 
 - (void)setAccessibilityAttributedLabel:(NSAttributedString *)newAccessibilityAttributedLabel
 {
-  if (![accessibilityAttributedLabel isEqualToAttributedString: newAccessibilityAttributedLabel]) {
+  if (! ASObjectIsEqual(accessibilityAttributedLabel, newAccessibilityAttributedLabel)) {
     _flags.setAccessibilityAttributedLabel = YES;
     _flags.setAccessibilityLabel = YES;
-    accessibilityAttributedLabel = [newAccessibilityAttributedLabel copy];
-    accessibilityLabel = [newAccessibilityAttributedLabel.string copy];
+    accessibilityAttributedLabel = newAccessibilityAttributedLabel ? [newAccessibilityAttributedLabel copy] : nil;
+    accessibilityLabel = newAccessibilityAttributedLabel ? [newAccessibilityAttributedLabel.string copy] : nil;
   }
 }
 
@@ -625,11 +626,11 @@ - (NSString *)accessibilityHint
 
 - (void)setAccessibilityHint:(NSString *)newAccessibilityHint
 {
-  if (![accessibilityHint isEqualToString:newAccessibilityHint]) {
+  if (! ASObjectIsEqual(accessibilityHint, newAccessibilityHint)) {
     _flags.setAccessibilityHint = YES;
     _flags.setAccessibilityAttributedHint = YES;
-    accessibilityHint = [newAccessibilityHint copy];
-    accessibilityAttributedHint = [[NSAttributedString alloc] initWithString:newAccessibilityHint];
+    accessibilityHint = newAccessibilityHint ? [newAccessibilityHint copy] : nil;
+    accessibilityAttributedHint = newAccessibilityHint ? [[NSAttributedString alloc] initWithString:newAccessibilityHint] : nil;
   }
 }
 
@@ -640,11 +641,11 @@ - (NSAttributedString *)accessibilityAttributedHint
 
 - (void)setAccessibilityAttributedHint:(NSAttributedString *)newAccessibilityAttributedHint
 {
-  if (![accessibilityAttributedHint isEqual:newAccessibilityAttributedHint]) {
+  if (! ASObjectIsEqual(accessibilityAttributedHint, newAccessibilityAttributedHint)) {
     _flags.setAccessibilityAttributedHint = YES;
     _flags.setAccessibilityHint = YES;
-    accessibilityAttributedHint = [newAccessibilityAttributedHint copy];
-    accessibilityHint = [newAccessibilityAttributedHint.string copy];
+    accessibilityAttributedHint = newAccessibilityAttributedHint ? [newAccessibilityAttributedHint copy] : nil;
+    accessibilityHint = newAccessibilityAttributedHint ? [newAccessibilityAttributedHint.string copy] : nil;
   }
 }
 
@@ -655,11 +656,11 @@ - (NSString *)accessibilityValue
 
 - (void)setAccessibilityValue:(NSString *)newAccessibilityValue
 {
-  if (![accessibilityValue isEqualToString:newAccessibilityValue]) {
+  if (! ASObjectIsEqual(accessibilityValue, newAccessibilityValue)) {
     _flags.setAccessibilityValue = YES;
     _flags.setAccessibilityAttributedValue = YES;
-    accessibilityValue = [newAccessibilityValue copy];
-    accessibilityAttributedValue = [[NSAttributedString alloc] initWithString:newAccessibilityValue];
+    accessibilityValue = newAccessibilityValue ? [newAccessibilityValue copy] : nil;
+    accessibilityAttributedValue = newAccessibilityValue ? [[NSAttributedString alloc] initWithString:newAccessibilityValue] : nil;
   }
 }
 
@@ -670,11 +671,11 @@ - (NSAttributedString *)accessibilityAttributedValue
 
 - (void)setAccessibilityAttributedValue:(NSAttributedString *)newAccessibilityAttributedValue
 {
-  if (![accessibilityAttributedValue isEqualToAttributedString:newAccessibilityAttributedValue]) {
+  if (! ASObjectIsEqual(accessibilityAttributedValue, newAccessibilityAttributedValue)) {
     _flags.setAccessibilityAttributedValue = YES;
     _flags.setAccessibilityValue = YES;
-    accessibilityAttributedValue = [newAccessibilityAttributedValue copy];
-    accessibilityValue = [newAccessibilityAttributedValue.string copy];
+    accessibilityAttributedValue = newAccessibilityAttributedValue?  [newAccessibilityAttributedValue copy] : nil;
+    accessibilityValue = newAccessibilityAttributedValue ? [newAccessibilityAttributedValue.string copy] : nil;
   }
 }
 

Tests/ASDisplayNodeTests.mm

@@ -518,9 +518,19 @@ - (void)checkSimpleBridgePropertiesSetPropagate:(BOOL)isLayerBacked
     node.debugName = @"quack like a duck";
 
     node.isAccessibilityElement = YES;
-    node.accessibilityLabel = @"Ship love";
-    node.accessibilityHint = @"Awesome things will happen";
-    node.accessibilityValue = @"1 of 2";
+
+    for (int i = 0; i < 4; i++) {
+      if (i % 2 == 0) {
+        XCTAssertNoThrow(node.accessibilityLabel = nil);
+        XCTAssertNoThrow(node.accessibilityHint = nil);
+        XCTAssertNoThrow(node.accessibilityValue = nil);
+      } else {
+        node.accessibilityLabel = @"Ship love";
+        node.accessibilityHint = @"Awesome things will happen";
+        node.accessibilityValue = @"1 of 2";
+      }
+    }
+
     node.accessibilityTraits = UIAccessibilityTraitSelected | UIAccessibilityTraitButton;
     node.accessibilityFrame = CGRectMake(1, 2, 3, 4);
     node.accessibilityLanguage = @"mas";