Fix a rare RC crash (#6556)

Author: paulb777

FirebaseRemoteConfig/CHANGELOG.md

@@ -1,3 +1,6 @@
+# v4.9.1
+- [fixed] Fix an `attempt to insert nil object` crash in `fetchWithExpirationDuration:`. (#6522)
+
 # v4.9.0
 - [fixed] Fixed `FirebaseApp.delete()` related crash in `RC Config Fetch`. (#6123)
 

FirebaseRemoteConfig/Sources/RCNConfigFetch.m

@@ -412,9 +412,9 @@ - (void)fetchWithUserProperties:(NSDictionary *)userProperties
         strongSelf->_settings.lastFetchError = FIRRemoteConfigErrorInternalError;
         NSDictionary<NSErrorUserInfoKey, id> *userInfo = @{
           NSLocalizedDescriptionKey :
-              (error ? [error localizedDescription]
-                     : [NSString
-                           stringWithFormat:@"Internal Error. Status code: %ld", (long)statusCode])
+              ([error localizedDescription]
+                   ?: [NSString
+                          stringWithFormat:@"Internal Error. Status code: %ld", (long)statusCode])
         };
         return [strongSelf
             reportCompletionOnHandler:completionHandler