FontFamily Exception：Value cannot be null. (Parameter 'name')

[plmm016]

Describe the bug
Some fonts may cause the app flash back，such as "小徐1599"

To Reproduce
TextBlock.Text = '小徐1599' or TextBox.Text = '小徐1599' or SelectableTextBlock..Text = '小徐1599'

Expected behavior
App don't flash back, and show fallback font with default string such as "小徐1599"

Screenshots
Exception Logs：

Fonts work fine in web：

Desktop (please complete the following information):

• OS: Windows 10
• Version: Avalonia 11.0.0

[JerryJian]

@Gillibald Has this issue been fixed by pull request #16120 ?

[Gillibald]

I am not sure what the actual issue is

[maxkatz6]

I am closing this issue. If it's still reproducible - let me know.

[JerryJian]

@maxkatz6 This problem occurred on my client's computer again, and I submit a PR (#16677) to fallback the font family to default when the fontFamilyName is null.

My exception is almost the same as the author's:

System.ArgumentNullException: Value cannot be null. (Parameter 'name')
   at Avalonia.Media.FontFamily..ctor(Uri baseUri, String name)
   at Avalonia.Media.FontFamily..ctor(String name)
   at Avalonia.Media.Typeface..ctor(String fontFamilyName, FontStyle style, FontWeight weight, FontStretch stretch)
   at Avalonia.Skia.FontManagerImpl.TryMatchCharacter(Int32 codepoint, FontStyle fontStyle, FontWeight fontWeight, FontStretch fontStretch, CultureInfo culture, Typeface& fontKey)
   at Avalonia.Media.FontManager.TryMatchCharacter(Int32 codepoint, FontStyle fontStyle, FontWeight fontWeight, FontStretch fontStretch, FontFamily fontFamily, CultureInfo culture, Typeface& typeface)
   at Avalonia.Media.TextFormatting.TextCharacters.CreateShapeableRun(ReadOnlyMemory`1 text, TextRunProperties defaultProperties, SByte biDiLevel, FontManager fontManager, TextRunProperties& previousProperties)
   at Avalonia.Media.TextFormatting.TextFormatterImpl.ShapeTextRuns(IReadOnlyList`1 textRuns, TextParagraphProperties paragraphProperties, FormattingObjectPool objectPool, FontManager fontManager, FlowDirection& resolvedFlowDirection)
   at Avalonia.Media.TextFormatting.TextFormatterImpl.FormatLine(ITextSource textSource, Int32 firstTextSourceIndex, Double paragraphWidth, TextParagraphProperties paragraphProperties, TextLineBreak previousLineBreak)
   at Avalonia.Media.TextFormatting.TextLayout.CreateTextLines()
   at Avalonia.Media.TextFormatting.TextLayout..ctor(ITextSource textSource, TextParagraphProperties paragraphProperties, TextTrimming textTrimming, Double maxWidth, Double maxHeight, Int32 maxLines)
   at Avalonia.Controls.TextBlock.CreateTextLayout(String text)
   at Avalonia.Controls.TextBlock.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Controls.StackPanel.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Controls.DockPanel.MeasureOverride(Size constraint)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.LayoutHelper.MeasureChild(Layoutable control, Size availableSize, Thickness padding, Thickness borderThickness)
   at Avalonia.Controls.Presenters.ContentPresenter.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Controls.VirtualizingStackPanel.RealizeElements(IReadOnlyList`1 items, Size availableSize, MeasureViewport& viewport)
   at Avalonia.Controls.VirtualizingStackPanel.MeasureOverride(Size availableSize)
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize)
   at Avalonia.Layout.Layoutable.Measure(Size availableSize)
   at Avalonia.Layout.LayoutManager.Measure(Layoutable control)
   at Avalonia.Layout.LayoutManager.ExecuteLayoutPass()
   at Avalonia.Media.MediaContext.FireInvokeOnRenderCallbacks()
   at Avalonia.Media.MediaContext.RenderCore()
   at Avalonia.Media.MediaContext.Render()
   at Avalonia.Threading.DispatcherOperation.InvokeCore()
   at Avalonia.Threading.DispatcherOperation.Execute()
   at Avalonia.Threading.Dispatcher.ExecuteJob(DispatcherOperation job)
   at Avalonia.Threading.Dispatcher.ExecuteJobsCore(Boolean fromExplicitBackgroundProcessingCallback)
   at Avalonia.Threading.Dispatcher.Signaled()
   at Avalonia.Win32.Win32Platform.WndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam)
   at Avalonia.Win32.Interop.UnmanagedMethods.DispatchMessage(MSG& lpmsg)
   at Avalonia.Win32.Win32DispatcherImpl.RunLoop(CancellationToken cancellationToken)
   at Avalonia.Threading.DispatcherFrame.Run(IControlledDispatcherImpl impl)
   at Avalonia.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at Avalonia.Threading.Dispatcher.MainLoop(CancellationToken cancellationToken)
   at Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(String[] args)