Fix mutation sorting function

Summary:
The sorting function currently forms a partial ordering, not a total ordering. This can cause problems with certain sequences of immediate or conflicting mutations, leading to UI corruption or crashes.

Changelog: [Internal]

Reviewed By: shergin

Differential Revision: D24002668

fbshipit-source-id: edc9b4c1e3104897cb0c5fd6da563ec43d800494

ReactCommon/react/renderer/animations/LayoutAnimationKeyFrameManager.h

@@ -308,6 +308,14 @@ static inline bool shouldFirstComeBeforeSecondMutation(
       return true;
     }
 
+    // Update comes last, before deletes
+    if (rhs.type == ShadowViewMutation::Type::Update) {
+      return true;
+    }
+    if (lhs.type == ShadowViewMutation::Type::Update) {
+      return false;
+    }
+
     // Remove comes before insert
     if (lhs.type == ShadowViewMutation::Type::Remove &&
         rhs.type == ShadowViewMutation::Type::Insert) {
@@ -317,6 +325,16 @@ static inline bool shouldFirstComeBeforeSecondMutation(
         lhs.type == ShadowViewMutation::Type::Insert) {
       return false;
     }
+
+    // Create comes before insert
+    if (lhs.type == ShadowViewMutation::Type::Create &&
+        rhs.type == ShadowViewMutation::Type::Insert) {
+      return true;
+    }
+    if (rhs.type == ShadowViewMutation::Type::Create &&
+        lhs.type == ShadowViewMutation::Type::Insert) {
+      return false;
+    }
   } else {
     // Make sure that removes on the same level are sorted - highest indices
     // must come first.