fix: Retry IAM fetch when OneSignal ID becomes available

When getInAppMessagesFromServer is called early in the app lifecycle while users are changing (e.g., login is called after initialize), the OneSignal ID may not be available yet, causing the fetch to fail silently. This fix ensures in-app messages are eventually fetched by:

- Adding OSUserStateObserver to OSMessagingController
- Storing the subscription ID when fetch fails due to missing OneSignal ID
- Retrying the fetch when user state changes and OneSignal ID becomes available

This prevents in-app messages from never being fetched when users are identified early in the app startup lifecycle.

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalInAppMessages/Controller/OSMessagingController.h

@@ -39,7 +39,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @end
 
-@interface OSMessagingController : NSObject <OSInAppMessageViewControllerDelegate, OSTriggerControllerDelegate, OSMessagingControllerDelegate, OSPushSubscriptionObserver>
+@interface OSMessagingController : NSObject <OSInAppMessageViewControllerDelegate, OSTriggerControllerDelegate, OSMessagingControllerDelegate, OSPushSubscriptionObserver, OSUserStateObserver>
 
 @property (class, readonly) BOOL isInAppMessagingPaused;
 

iOS_SDK/OneSignalSDK/OneSignalInAppMessages/Controller/OSMessagingController.m

@@ -146,6 +146,9 @@ @interface OSMessagingController ()
 
 @property (nonatomic) BOOL calledLoadTags;
 
+/// set when we attempt getInAppMessagesFromServer and no onesignal ID is available yet
+@property (strong, nonatomic, nullable) NSString *shouldFetchOnUserChangeWithSubscriptionID;
+
 @end
 
 @implementation OSMessagingController
@@ -175,6 +178,7 @@ + (void)removeInstance {
 + (void)start {
     OSMessagingController *shared = OSMessagingController.sharedInstance;
     [OneSignalUserManagerImpl.sharedInstance.pushSubscriptionImpl addObserver:shared];
+    [OneSignalUserManagerImpl.sharedInstance addObserver:shared];
 }
 
 static BOOL _isInAppMessagingPaused = false;
@@ -254,8 +258,10 @@ - (void)getInAppMessagesFromServer:(NSString *)subscriptionId {
         OSConsistencyManager *consistencyManager = [OSConsistencyManager shared];
         NSString *onesignalId = OneSignalUserManagerImpl.sharedInstance.onesignalId;
 
+        // NOTE: Check for subscription ID above first, before checking for OneSignal ID next
         if (!onesignalId) {
-            [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"Failed to get in app messages due to no OneSignal ID"];
+            [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"Failed to get in app messages due to no OneSignal ID, will reattempt"];
+            self.shouldFetchOnUserChangeWithSubscriptionID = subscriptionId;
             return;
         }
 
@@ -1198,6 +1204,15 @@ - (void)onPushSubscriptionDidChangeWithState:(OSPushSubscriptionChangedState * _
     [self getInAppMessagesFromServer:state.current.id];
 }
 
+- (void)onUserStateDidChangeWithState:(OSUserChangedState * _Nonnull)state {
+    if (state.current.onesignalId != nil && self.shouldFetchOnUserChangeWithSubscriptionID) {
+        [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"OSMessagingController onUserStateDidChangeWithState: changed to new valid onesignal id"];
+        NSString *subscriptionID = self.shouldFetchOnUserChangeWithSubscriptionID;
+        self.shouldFetchOnUserChangeWithSubscriptionID = nil;
+        [self getInAppMessagesFromServer:subscriptionID];
+    }
+}
+
 - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self];
 }