System.InvalidOperationException: Default font family name can't be null or empty

Version: 0.10-preview2

I upgraded project IPOCS.JMRI.CONTROL, located at https://github.com/GMJS/ipocs.jmri, to preview2 (not committed and pushed yet) and made a build for linux-arm using dotnet publish IPOCS.JMRI.CONTROL -c Release -r linux-arm. Upon trying to run this on a raspberry pi I’m getting the exception:

Unhandled exception. System.InvalidOperationException: Default font family name can't be null or empty.
   at Avalonia.Media.FontManager..ctor(IFontManagerImpl platformImpl)
   at Avalonia.Media.FontManager.get_Current()
   at Avalonia.Rendering.RendererBase..ctor(Boolean useManualFpsCounting)
   at Avalonia.Rendering.DeferredRenderer..ctor(IRenderRoot root, IRenderLoop renderLoop, ISceneBuilder sceneBuilder, IDispatcher dispatcher, IDeferredRendererLock rendererLock)
   at Avalonia.X11.X11Window.CreateRenderer(IRenderRoot root)
   at Avalonia.Controls.TopLevel..ctor(ITopLevelImpl impl, IAvaloniaDependencyResolver dependencyResolver)
   at Avalonia.Controls.WindowBase..ctor(IWindowBaseImpl impl, IAvaloniaDependencyResolver dependencyResolver)
   at Avalonia.Controls.WindowBase..ctor(IWindowBaseImpl impl)
   at Avalonia.Controls.Window..ctor(IWindowImpl impl)
   at Avalonia.Controls.Window..ctor()
   at IPOCS.JMRI.CONTROL.Views.MainWindow..ctor() in <path>\ipocs.jmri\IPOCS.JMRI.CONTROL\Views\MainWindow.axaml.cs:line 9
   at IPOCS.JMRI.CONTROL.App.OnFrameworkInitializationCompleted() in <path>t\ipocs.jmri\IPOCS.JMRI.CONTROL\App.axaml.cs:line 20
   at Avalonia.Controls.AppBuilderBase`1.Setup()
   at Avalonia.Controls.AppBuilderBase`1.SetupWithLifetime(IApplicationLifetime lifetime)
   at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime[T](T builder, String[] args, ShutdownMode shutdownMode)
   at IPOCS.JMRI.CONTROL.Program.Main(String[] args) in <path>\ipocs.jmri\IPOCS.JMRI.CONTROL\Program.cs:line 13

[ThePBone]

This issue is also happening when the system language is set to Korean or Japanese and probably any other language with non-Latin characters as well. (tested on a fresh Ubuntu 20.10 VM x86_64)

I can fix this font loading issue by launching my app with a modified locale environment variable:

LC_ALL=C ./YourAvaloniaExecutable

[vddCore]

i use arch btw ArchLinux here, same issue. Fixed by installing this package and running fc-cache --force.

All that package contains are fonts and licenses, and the fonts installed are as follows:

AndaleMo.TTF  Arialbd.TTF   Comic.TTF     Georgiab.TTF
Impact.TTF    Timesbi.TTF   Verdana.TTF   Verdanaz.TTF
courbd.ttf    trebuc.ttf    AriBlk.TTF    Arialbi.TTF  
Comicbd.TTF   Georgiai.TTF  Times.TTF     Timesi.TTF    
Verdanab.TTF  Webdings.TTF  courbi.ttf    trebucbi.ttf
Arial.TTF     Ariali.TTF    Georgia.TTF   Georgiaz.TTF  
Timesbd.TTF   Trebucbd.ttf  Verdanai.TTF  cour.ttf  
couri.ttf     trebucit.ttf

After further testing it looks like something in the font management chain really likes Verdana font for whatever reason, and if Verdana (all of its variants) goes missing it tries to look for any available variants of the Arial font, furthermore - when Arial is removed the previously mentioned InvalidOperationException is thrown.