remove retain_previous_user flag

* No longer accepted by the server when transferring a push subscription.
* Server checks anonymous user for whether it has any aliases set. If so, we’ll keep the user. If there aren’t aliases, we’ll remove it. Done behind the scenes in Perseus.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalCore/Source/OneSignalCommonDefines.h

@@ -278,7 +278,6 @@ typedef enum {GET, POST, HEAD, PUT, DELETE, OPTIONS, CONNECT, TRACE, PATCH} HTTP
 #define OS_ONESIGNAL_ID                                                     @"onesignal_id"
 #define OS_EXTERNAL_ID                                                      @"external_id"
 
-#define OS_RETAIN_PREVIOUS_USER                                             @"retain_previous_user"
 #define OS_ON_USER_WILL_CHANGE                                              @"OS_ON_USER_WILL_CHANGE"
 
 // Models and Model Stores

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSUserRequests.swift

@@ -382,13 +382,12 @@ class OSUserExecutor {
         }
     }
 
-    static func transferPushSubscriptionTo(aliasLabel: String, aliasId: String, retainPreviousUser: Bool?) {
+    static func transferPushSubscriptionTo(aliasLabel: String, aliasId: String) {
         // TODO: Where to get pushSubscriptionModel for this request
         let request = OSRequestTransferSubscription(
             subscriptionModel: OneSignalUserManagerImpl.sharedInstance.user.pushSubscriptionModel,
             aliasLabel: aliasLabel,
-            aliasId: aliasId,
-            retainPreviousUser: retainPreviousUser // Need to update logic to determine this, for now, default to true
+            aliasId: aliasId
         )
 
         appendToQueue(request)
@@ -1036,9 +1035,6 @@ class OSRequestTransferSubscription: OneSignalRequest, OSUserRequest {
     func prepareForExecution() -> Bool {
         if let subscriptionId = subscriptionModel.subscriptionId, let appId = OneSignalConfigManager.getAppId() {
             self.path = "apps/\(appId)/subscriptions/\(subscriptionId)/owner"
-            // Check alias pair
-            // parameters should be set in init(), so not optional
-            self.parameters?["identity"] = [aliasLabel: aliasId]
             // TODO: self.addJWTHeader(identityModel: identityModel) ??
             return true
         } else {
@@ -1049,20 +1045,18 @@ class OSRequestTransferSubscription: OneSignalRequest, OSUserRequest {
 
     /**
      Must pass an Alias pair to identify the User.
-     If `retainPreviousUser` flag is not passed in, it defaults to `true`.
      */
     init(
         subscriptionModel: OSSubscriptionModel,
         aliasLabel: String,
-        aliasId: String,
-        retainPreviousUser: Bool?
+        aliasId: String
     ) {
         self.subscriptionModel = subscriptionModel
         self.aliasLabel = aliasLabel
         self.aliasId = aliasId
         self.stringDescription = "OSRequestTransferSubscription"
         super.init()
-        self.parameters = [OS_RETAIN_PREVIOUS_USER: retainPreviousUser ?? true]
+        self.parameters = ["identity": [aliasLabel: aliasId]]
         self.method = PATCH
         _ = prepareForExecution() // sets the path property
     }