BindingExpressionBase.UpdateNotifyDataErrorValidationErrors throws NullReferenceException

[znakeeye]

Description

Targeting .NET 6. This happened twice, but I have no reliable way to reproduce it.

PresentationFramework.dll!System.Windows.Data.BindingExpressionBase.UpdateNotifyDataErrorValidationErrors(System.Collections.Generic.List<object> errors) Unknown
PresentationFramework.dll!System.Windows.Data.BindingExpression.UpdateNotifyDataErrors(System.ComponentModel.INotifyDataErrorInfo indei, string propertyName, object value)   Unknown
PresentationFramework.dll!System.Windows.Data.BindingExpression.OnErrorsChanged.AnonymousMethod__108_0(object arg)       Unknown
               PresentationFramework.dll!MS.Internal.Data.DataBindEngine.ProcessCrossThreadRequests()                Unknown
        WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs) Unknown
               WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.TryCatchWhen(object source, System.Delegate callback, object args, int numArgs, System.Delegate catchHandler)               Unknown
               WindowsBase.dll!System.Windows.Threading.DispatcherOperation.InvokeImpl()       Unknown
               WindowsBase.dll!MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(object obj)                Unknown
> System.Private.CoreLib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Line 179           C#
WindowsBase.dll!MS.Internal.CulturePreservingExecutionContext.Run(MS.Internal.CulturePreservingExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
               WindowsBase.dll!System.Windows.Threading.DispatcherOperation.Invoke()  Unknown
               WindowsBase.dll!System.Windows.Threading.Dispatcher.ProcessQueue()      Unknown
               WindowsBase.dll!System.Windows.Threading.Dispatcher.WndProcHook(nint hwnd, int msg, nint wParam, nint lParam, ref bool handled)             Unknown
               WindowsBase.dll!MS.Win32.HwndWrapper.WndProc(nint hwnd, int msg, nint wParam, nint lParam, ref bool handled)      Unknown
        WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate callback, object args, int numArgs) Unknown
               WindowsBase.dll!System.Windows.Threading.ExceptionWrapper.TryCatchWhen(object source, System.Delegate callback, object args, int numArgs, System.Delegate catchHandler)               Unknown
WindowsBase.dll!System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority priority, System.TimeSpan timeout, System.Delegate method, object args, int numArgs)         Unknown
               WindowsBase.dll!MS.Win32.HwndSubclass.SubclassWndProc(nint hwnd, int msg, nint wParam, nint lParam)              Unknown
               [Native to Managed Transition]          
               [Managed to Native Transition]          
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame) Unknown
               PresentationFramework.dll!System.Windows.Application.RunDispatcher(object ignore)                Unknown
               PresentationFramework.dll!System.Windows.Application.RunInternal(System.Windows.Window window)            Unknown

Reproduction Steps

No way to reproduce it. You will have to perform some static analysis...

Expected behavior

We should not get a NullReferenceException for each item in the rendered items control.

Actual behavior

A NullReferenceException is thrown for each item in our bound list.

Regression?

No response

Known Workarounds

No response

Impact

No response

Configuration

No response

Other information

We are using BindingOperations.EnableCollectionSynchronization() on our custom ObservableCollection, if that matters. (This code has been in production for several years, and we never encountere this prior to .NET Core migration.)

[himgoyalmicro]

@znakeeye Can you please provide more information about the use case where you are encountering the NRE exception?