InvalidOperationException from valid PathFigure definition

• .NET Core Version: 6.0.9
• Windows version: 10.0.19044 Build 19044
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes
• Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc…)? No
• Security issues and bugs should be reported privately, learn more via our responsible disclosure guidelines.

Problem description:

The program throws an exception rather than running.

Actual behavior:

System.Windows.Markup.XamlParseException: 'Set property 'System.Windows.Shapes.Path.Data' threw an exception.' Line number '14' and line position '19'. ---> System.InvalidOperationException: Current local value enumeration is outdated because one or more local values have been set since its creation.
   at System.Windows.DependencyObject.InsertEntry(EffectiveValueEntry entry, UInt32 entryIndex)
   at System.Windows.DependencyObject.SetEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, Int32 targetIndex, PropertyMetadata metadata, Object value, BaseValueSourceInternal valueSource)
   at System.Windows.UncommonField`1.SetValue(DependencyObject instance, T value)
   at System.Windows.DependencyObject.UpdateSourceDependentLists(DependencyObject d, DependencyProperty dp, DependencySource[] sources, Expression expr, Boolean add)
   at System.Windows.DependencyObject.ChangeExpressionSources(Expression expr, DependencyObject d, DependencyProperty dp, DependencySource[] newSources)
   at System.Windows.Data.BindingExpressionBase.ChangeSources(WeakDependencySource[] newSources)
   at MS.Internal.Data.ClrBindingWorker.ReplaceDependencySources()
   at MS.Internal.Data.ClrBindingWorker.NewValueAvailable(Boolean dependencySourcesChanged, Boolean initialValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.PropertyPathWorker.UpdateSourceValueState(Int32 k, ICollectionView collectionView, Object newValue, Boolean isASubPropertyChange)
   at MS.Internal.Data.ClrBindingWorker.AttachDataItem()
   at System.Windows.Data.BindingExpression.Activate(Object item)
   at System.Windows.Data.BindingExpression.AttachToContext(AttachAttempt attempt)
   at System.Windows.Data.BindingExpression.OnInheritanceContextChanged(Object sender, EventArgs e)
   at System.Windows.WeakEventManager.ListenerList`1.DeliverEvent(Object sender, EventArgs e, Type managerType)
   at System.Windows.WeakEventManager.DeliverEvent(Object sender, EventArgs args)
   at System.Windows.DependencyObject.OnInheritanceContextChanged(EventArgs args)
   at System.Windows.Media.PathSegmentCollection.OnInheritanceContextChangedCore(EventArgs args)
   at System.Windows.DependencyObject.OnInheritanceContextChanged(EventArgs args)
   at System.Windows.Media.PathFigureCollection.OnInheritanceContextChangedCore(EventArgs args)
   at System.Windows.DependencyObject.OnInheritanceContextChanged(EventArgs args)
   at System.Windows.Freezable.AddInheritanceContext(DependencyObject context, DependencyProperty property)
   at System.Windows.DependencyObject.ProvideSelfAsInheritanceContext(DependencyObject doValue, DependencyProperty dp)
   at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType)
   at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, Boolean coerceWithCurrentValue, OperationType operationType, Boolean isInternal)
   at System.Windows.Baml2006.WpfKnownMemberInvoker.SetValue(Object instance, Object value)
   at MS.Internal.Xaml.Runtime.ClrObjectRuntime.SetValue(Object inst, XamlMember property, Object value)
   --- End of inner exception stack trace ---
   at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
   at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
   at PathFigureRepro.MainWindow.InitializeComponent() in C:\Users\Lyndon.G\Desktop\PathFigureRepro\PathFigureRepro\MainWindow.xaml:line 1
   at PathFigureRepro.MainWindow..ctor() in C:\Users\Lyndon.G\Desktop\PathFigureRepro\PathFigureRepro\MainWindow.xaml.cs:line 25

Expected behavior:

Program runs

Minimal repro:

<Path Stroke="HotPink" StrokeThickness="1">
    <Path.Data>
        <PathGeometry>
            <PathFigure x:Name="StartFigure">
                <LineSegment Point="{Binding StartPoint, ElementName=StartFigure}" />
            </PathFigure>
        </PathGeometry>
    </Path.Data>
</Path>

PathFigureRepro.zip

(Stolen from MSDN Forums after experiencing a similar exception)

[LyndonGingerich]

Here’s an MRE from the Behavior I was writing when I encountered this exception.

PathFigureRepro.zip

[LyndonGingerich]

(just in case, PathFigure has IsClosed for this purpose)

True. This is a mere MRE. If you want a more convincing use case, I’ll post my Behavior code.

I am guessing not the easiest one to fix 😃

Bummer.