Fix Text Node Thread Sanitizer Warning (TextureGroup#830)

* Fix thread sanitizer warning in ASTextNodeRendererKey

* Update changelog

* Comment on missing class check

CHANGELOG.md

@@ -33,6 +33,7 @@
 - Pass scrollViewWillEndDragging delegation through in ASIGListAdapterDataSource for IGListKit integration. [#796](https://github.com/TextureGroup/Texture/pull/796)
 - Fix UIResponder handling with view backing ASDisplayNode. [Michael Schneider](https://github.com/maicki) [#789] (https://github.com/TextureGroup/Texture/pull/789/)
 - Optimized thread-local storage by replacing pthread_specific with C11 thread-local variables. [Adlai Holler](https://github.com/Adlai-Holler) [#811] (https://github.com/TextureGroup/Texture/pull/811/)
+- Fixed a thread-sanitizer warning in ASTextNode. [Adlai Holler](https://github.com/Adlai-Holler) [#830] (https://github.com/TextureGroup/Texture/pull/830/)
 
 ## 2.6
 - [Xcode 9] Updated to require Xcode 9 (to fix warnings) [Garrett Moon](https://github.com/garrettmoon)

Source/ASTextNode.mm

@@ -63,10 +63,13 @@ @interface ASTextNodeRendererKey : NSObject
 @property (assign, nonatomic) CGSize constrainedSize;
 @end
 
-@implementation ASTextNodeRendererKey
+@implementation ASTextNodeRendererKey {
+  std::mutex _m;
+}
 
 - (NSUInteger)hash
 {
+  std::lock_guard<std::mutex> _l(_m);
 #pragma clang diagnostic push
 #pragma clang diagnostic warning "-Wpadded"
   struct {
@@ -86,7 +89,14 @@ - (BOOL)isEqual:(ASTextNodeRendererKey *)object
     return YES;
   }
 
-  return _attributes == object.attributes && CGSizeEqualToSize(_constrainedSize, object.constrainedSize);
+  // NOTE: Skip the class check for this specialized, internal Key object.
+
+  // Lock both objects, avoiding deadlock.
+  std::lock(_m, object->_m);
+  std::lock_guard<std::mutex> lk1(_m, std::adopt_lock);
+  std::lock_guard<std::mutex> lk2(object->_m, std::adopt_lock);
+
+  return _attributes == object->_attributes && CGSizeEqualToSize(_constrainedSize, object->_constrainedSize);
 }
 
 @end