Fire user observer on logout (JWT on)

* Usually, on logout, the user observer will fire once the anonymous user is created to the backend and returns with an OSID. However, when Identity Verification is on, that will not happen, so fire the observer early with `nil` values to represent there is no user in the SDK currently.
* Firing the observer will save the state and necessary to know when the user logs back in. This is used by the messaging controller to fetch IAM appropriately. On a new session, it will not fetch IAM if logged out, but as the user observer, it will fetch once a user logs in.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalUser/Source/Modeling/OSIdentityModel.swift

@@ -134,26 +134,6 @@ class OSIdentityModel: OSModel {
         let newExternalId = remoteAliases[OS_EXTERNAL_ID]
 
         internalAddAliases(remoteAliases)
-        fireUserStateChanged(newOnesignalId: newOnesignalId, newExternalId: newExternalId)
-    }
-
-    /**
-     Fires the user observer if `onesignal_id` OR `external_id` has changed from the previous snapshot (previous hydration).
-     */
-    private func fireUserStateChanged(newOnesignalId: String?, newExternalId: String?) {
-        let prevOnesignalId  = OneSignalUserDefaults.initShared().getSavedString(forKey: OS_SNAPSHOT_ONESIGNAL_ID, defaultValue: nil)
-        let prevExternalId = OneSignalUserDefaults.initShared().getSavedString(forKey: OS_SNAPSHOT_EXTERNAL_ID, defaultValue: nil)
-
-        guard prevOnesignalId != newOnesignalId || prevExternalId != newExternalId else {
-            return
-        }
-
-        OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_ONESIGNAL_ID, withValue: newOnesignalId)
-        OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_EXTERNAL_ID, withValue: newExternalId)
-
-        let curUserState = OSUserState(onesignalId: newOnesignalId, externalId: newExternalId)
-        let changedState = OSUserChangedState(current: curUserState)
-
-        OneSignalUserManagerImpl.sharedInstance.userStateChangesObserver.notifyChange(changedState)
+        OSUserUtils.fireUserStateChanged(newOnesignalId: newOnesignalId, newExternalId: newExternalId)
     }
 }

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OneSignalUserManagerImpl.swift

@@ -447,9 +447,13 @@ public class OneSignalUserManagerImpl: NSObject, OneSignalUserManager {
 
         /*
          If Identity Verification is on, disable the push subscription.
+         Since the anonymous placeholder user will not be created to the backend,
+         fire the user observer here to represent "no user" in the SDK.
+         This is necessary so internal user observers can know when a user logs out and then back in.
          */
         if jwtConfig.isRequired == true {
             user.pushSubscriptionModel._isDisabledInternally = true
+            OSUserUtils.fireUserStateChanged(newOnesignalId: nil, newExternalId: nil)
         }
     }
 

iOS_SDK/OneSignalSDK/OneSignalUser/Source/Support/OSUserUtils.swift

@@ -71,4 +71,24 @@ class OSUserUtils {
         }
         return headers
     }
+
+    /**
+     Fires the user observer if `onesignal_id` OR `external_id` has changed from the previous snapshot (previous hydration).
+     */
+    static func fireUserStateChanged(newOnesignalId: String?, newExternalId: String?) {
+        let prevOnesignalId  = OneSignalUserDefaults.initShared().getSavedString(forKey: OS_SNAPSHOT_ONESIGNAL_ID, defaultValue: nil)
+        let prevExternalId = OneSignalUserDefaults.initShared().getSavedString(forKey: OS_SNAPSHOT_EXTERNAL_ID, defaultValue: nil)
+
+        guard prevOnesignalId != newOnesignalId || prevExternalId != newExternalId else {
+            return
+        }
+
+        OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_ONESIGNAL_ID, withValue: newOnesignalId)
+        OneSignalUserDefaults.initShared().saveString(forKey: OS_SNAPSHOT_EXTERNAL_ID, withValue: newExternalId)
+
+        let curUserState = OSUserState(onesignalId: newOnesignalId, externalId: newExternalId)
+        let changedState = OSUserChangedState(current: curUserState)
+
+        OneSignalUserManagerImpl.sharedInstance.userStateChangesObserver.notifyChange(changedState)
+    }
 }