[PM-16482]NullReferenceException in CustomerUpdatedHandler due to uninitialized dependency (#5349)

* Changes to throw exact errors

* Add some logging to each error state

Signed-off-by: Cy Okeke <cokeke@bitwarden.com>

---------

Signed-off-by: Cy Okeke <cokeke@bitwarden.com>

src/Billing/Services/Implementations/CustomerUpdatedHandler.cs

@@ -14,19 +14,22 @@ public class CustomerUpdatedHandler : ICustomerUpdatedHandler
     private readonly ICurrentContext _currentContext;
     private readonly IStripeEventService _stripeEventService;
     private readonly IStripeEventUtilityService _stripeEventUtilityService;
+    private readonly ILogger<CustomerUpdatedHandler> _logger;
 
     public CustomerUpdatedHandler(
         IOrganizationRepository organizationRepository,
         IReferenceEventService referenceEventService,
         ICurrentContext currentContext,
         IStripeEventService stripeEventService,
-        IStripeEventUtilityService stripeEventUtilityService)
+        IStripeEventUtilityService stripeEventUtilityService,
+        ILogger<CustomerUpdatedHandler> logger)
     {
-        _organizationRepository = organizationRepository;
+        _organizationRepository = organizationRepository ?? throw new ArgumentNullException(nameof(organizationRepository));
         _referenceEventService = referenceEventService;
         _currentContext = currentContext;
         _stripeEventService = stripeEventService;
         _stripeEventUtilityService = stripeEventUtilityService;
+        _logger = logger;
     }
 
     /// <summary>
@@ -35,25 +38,76 @@ public class CustomerUpdatedHandler : ICustomerUpdatedHandler
     /// <param name="parsedEvent"></param>
     public async Task HandleAsync(Event parsedEvent)
     {
-        var customer = await _stripeEventService.GetCustomer(parsedEvent, true, ["subscriptions"]);
+        if (parsedEvent == null)
-        if (customer.Subscriptions == null || !customer.Subscriptions.Any())
         {
+            _logger.LogError("Parsed event was null in CustomerUpdatedHandler");
+            throw new ArgumentNullException(nameof(parsedEvent));
+        }
+
+        if (_stripeEventService == null)
+        {
+            _logger.LogError("StripeEventService was not initialized in CustomerUpdatedHandler");
+            throw new InvalidOperationException($"{nameof(_stripeEventService)} is not initialized");
+        }
+
+        var customer = await _stripeEventService.GetCustomer(parsedEvent, true, ["subscriptions"]);
+        if (customer?.Subscriptions == null || !customer.Subscriptions.Any())
+        {
+            _logger.LogWarning("Customer or subscriptions were null or empty in CustomerUpdatedHandler. Customer ID: {CustomerId}", customer?.Id);
             return;
         }
 
         var subscription = customer.Subscriptions.First();
 
+        if (subscription.Metadata == null)
+        {
+            _logger.LogWarning("Subscription metadata was null in CustomerUpdatedHandler. Subscription ID: {SubscriptionId}", subscription.Id);
+            return;
+        }
+
+        if (_stripeEventUtilityService == null)
+        {
+            _logger.LogError("StripeEventUtilityService was not initialized in CustomerUpdatedHandler");
+            throw new InvalidOperationException($"{nameof(_stripeEventUtilityService)} is not initialized");
+        }
+
         var (organizationId, _, providerId) = _stripeEventUtilityService.GetIdsFromMetadata(subscription.Metadata);
 
         if (!organizationId.HasValue)
         {
+            _logger.LogWarning("Organization ID was not found in subscription metadata. Subscription ID: {SubscriptionId}", subscription.Id);
             return;
         }
 
+        if (_organizationRepository == null)
+        {
+            _logger.LogError("OrganizationRepository was not initialized in CustomerUpdatedHandler");
+            throw new InvalidOperationException($"{nameof(_organizationRepository)} is not initialized");
+        }
+
         var organization = await _organizationRepository.GetByIdAsync(organizationId.Value);
+
+        if (organization == null)
+        {
+            _logger.LogWarning("Organization not found. Organization ID: {OrganizationId}", organizationId.Value);
+            return;
+        }
+
         organization.BillingEmail = customer.Email;
         await _organizationRepository.ReplaceAsync(organization);
 
+        if (_referenceEventService == null)
+        {
+            _logger.LogError("ReferenceEventService was not initialized in CustomerUpdatedHandler");
+            throw new InvalidOperationException($"{nameof(_referenceEventService)} is not initialized");
+        }
+
+        if (_currentContext == null)
+        {
+            _logger.LogError("CurrentContext was not initialized in CustomerUpdatedHandler");
+            throw new InvalidOperationException($"{nameof(_currentContext)} is not initialized");
+        }
+
         await _referenceEventService.RaiseEventAsync(
             new ReferenceEvent(ReferenceEventType.OrganizationEditedInStripe, organization, _currentContext));
     }