tracking NullReferenceExceptions in sitecore

Question

i'm trying to track a NullReferenceException that shows up on sitecore 6.5 at loading any webpage:

[NullReferenceException: Object reference not set to an instance of an object.]
   Sitecore.Diagnostics.Log.Error(String message, Exception exception, Type ownerType) +133
   Sitecore.Diagnostics.Log.Error(String message, Type ownerType) +45
   Sitecore.Configuration.Factory.LoadAutoIncludeFiles(ConfigPatcher patcher, String folder) +680
   Sitecore.Configuration.Factory.LoadAutoIncludeFiles(XmlNode element) +63
   Sitecore.Configuration.Factory.GetConfiguration() +347
   Sitecore.Diagnostics.LoggerFactory..cctor() +67

[TypeInitializationException: The type initializer for 'Sitecore.Diagnostics.LoggerFactory' threw an exception.]
   Sitecore.Diagnostics.LoggerFactory.GetLogger(Type type) +17
   Sitecore.Diagnostics.Log.Error(String message, Exception exception, Type ownerType) +93
   Sitecore.Diagnostics.Log.Error(String message, Type ownerType) +45
   Sitecore.Configuration.Factory.LoadAutoIncludeFiles(ConfigPatcher patcher, String folder) +680
   Sitecore.Configuration.Factory.LoadAutoIncludeFiles(XmlNode element) +63
   Sitecore.Configuration.Factory.GetConfiguration() +347
   Sitecore.Configuration.Factory.GetConfigNode(String xpath, Boolean assert) +82
   Sitecore.Configuration.Factory.GetConfigNode(String xpath) +29
   Sitecore.Resources.Media.UploadWatcher.InitializeIgnoreList() +114
   Sitecore.Resources.Media.UploadWatcher..cctor() +51

[TypeInitializationException: The type initializer for 'Sitecore.Resources.Media.UploadWatcher' threw an exception.]
   Sitecore.Resources.Media.UploadWatcher..ctor() +0

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
   System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) +98
   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) +241
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +69
   System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +1136
   System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +111
   System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) +23
   System.Web.HttpRuntime.CreateNonPublicInstance(Type type, Object[] args) +60
   System.Web.HttpApplication.BuildIntegratedModuleCollection(List`1 moduleList) +231
   System.Web.HttpApplication.GetModuleCollection(IntPtr appContext) +1365
   Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleReflectionUtil.GetIntegratedModuleCollection(HttpApplication target, IntPtr appContext) +33
   Microsoft.Web.Infrastructure.DynamicModuleHelper.CriticalStatics.Init(HttpApplication context) +179
   Microsoft.Web.Infrastructure.DynamicModuleHelper.IntegratedDynamicModule.Init(HttpApplication context) +6
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +517
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +194
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +339
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +253

[HttpException (0x80004005): Exception has been thrown by the target of an invocation.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9087676
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +97
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +256

the interesting characteristics that make this error hard to track are the following:

1) i get the following error in the sitecore log:

Exception: System.InvalidOperationException
Message: 'analytics' connection string is not defined
Source: Sitecore.Kernel
   at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
   at Sitecore.Diagnostics.Assert.ResultNotNull[T](T result, String message)
   at Sitecore.Analytics.Data.DataAccess.DataAdapters.DataAdapterManager.ConnectionStrings.get_AnalyticsSettings()
   at Sitecore.Analytics.Data.DataAccess.DataAdapters.DataAdapterManager.ConnectionStrings.get_Analytics()
   at Sitecore.Analytics.Data.DataAccess.DataAdapters.Sql.SqlServer.SqlServerDataAdapterProvider..ctor()

however analytics is very well disabled:

<setting name="Analytics.DisableDatabase" value="true" />
...
<setting name="Analytics.Enabled" value="false" />

2) the error goes away when i debug with visual studio, attach to IIS, and hit at least one breakpoint (if i don't hit any breakpoint, the error stays)

3) the error shows up again when i do a build, or touch web.config. Haven't tried rebuild, as that will delete important sitecore dlls from Website/bin

more info about my environment: visual studio 2010, IIS 7, sitecore 6.5, windows 7

how would you track this error?

Answer 1

I had the exact same problem (my stack trace was the same as the one posted) and it turned out to be a malformed .config file in the App_Config\Include folder. Fixed the config and my site loaded without problems.

Answer 2

Looks like an "include" config file is missing from your setup. Decompile Sitecore.Resources.Media.UploadWatcher.InitializeIgnoreList to try to work out which one (sorry haven't got a decompiler handy). Reflector comes with a 30-day trial or Telerik Just Decompile is free.

EDIT I use a product called SlowCheetah which does XML transformations based on build configuration for any XML file, not just web.config like VS does. You can NuGet it. Highly Recommended.

Answer 3

I had the same problem, i found out if your config files don't have the <sitecore> node you will get a error like this!