Synchronize State

• Fixes a crash where the generateJsonDiff() method of the currentUserState property in UserStateSynchronizer is called before the currentUserState is initialized, by adding a synchronization step to the initUserState() method
• Adds a check to make sure the user state is initialized before internalSyncUserState() attempts to access it.

Author: Nightsd01

OneSignalSDK/onesignal/src/main/java/com/onesignal/UserStateSynchronizer.java

@@ -119,8 +119,10 @@ protected synchronized UserState getToSyncUserState() {
     }
 
     void initUserState() {
-        if (currentUserState == null)
-            currentUserState = newUserState("CURRENT_STATE", true);
+        synchronized (syncLock) {
+            if (currentUserState == null)
+                currentUserState = newUserState("CURRENT_STATE", true);
+        }
 
         getToSyncUserState();
     }
@@ -167,6 +169,9 @@ private void internalSyncUserState(boolean fromSyncService) {
             return;
         }
 
+        if (currentUserState == null)
+            initUserState();
+
         final boolean isSessionCall = isSessionCall();
         JSONObject jsonBody, dependDiff;
         synchronized (syncLock) {