System.Windows.Markup.XamlParseException in System.Runtime when published trimmed

[Symbai]

Description

Publishing a WPF application using the trim unused assemblies option (VS -> Build dialog) throws a System.Windows.Markup.XamlParseException on start of the application. Publishing untrimmed works fine.

Configuration

Other information

 OS Name:     Windows
 OS Version:  10.0.19042
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.201\

Host (useful for support):
  Version: 5.0.4
  Commit:  f27d337295

System.Windows.Markup.XamlParseException: An exception was thrown by calling the constructor for type "Aaaa.MainWindow" that matches the specified binding restrictions.

 ---> System.TypeInitializationException: The type initializer for 'System.Windows.Window' threw an exception.
 ---> System.TypeInitializationException: The type initializer for 'System.Windows.FrameworkElement' threw an exception.
 ---> System.TypeInitializationException: The type initializer for 'System.Windows.Documents.TextElement' threw an exception.
 ---> System.TypeInitializationException: The type initializer for 'System.Windows.Documents.Typography' threw an exception.
 ---> System.IO.FileNotFoundException:

File name: 'System.Runtime, Version = 5.0.0.0, Culture = neutral, PublicKeyToken = b03f5f7f11d50a3a'
   at System.Windows.Media.TextFormatting.TextRunTypographyProperties.OnPropertiesChanged ()
   at MS.Internal.Text.TypographyProperties.ResetProperties ()
   at MS.Internal.Text.TypographyProperties..ctor ()
   at System.Windows.Documents.Typography..cctor ()
   --- End of inner exception stack trace ---
   at System.Windows.Documents.TextElement..cctor ()
   --- End of inner exception stack trace ---
   at System.Windows.FrameworkElement..cctor ()
   --- End of inner exception stack trace ---
   at System.Windows.Window..cctor ()
   --- End of inner exception stack trace ---
   at System.Windows.Window..ctor ()
   at Aaaa.MainWindow..ctor ()
   --- 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 System.Windows.Application.LoadBamlStreamWithSyncInfo (Stream stream, ParserContext pc)
   at System.Windows.Application.LoadComponent (Uri resourceLocator, Boolean bSkipJournaledProperties)
   at System.Windows.Application.DoStartup ()
   at System.Windows.Application. <. ctor> b__1_0 (Object unused)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall (Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen (Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

The trim feature has removed the following files, several of them sounds pretty much mandatory for EVERY app to me and shouldn't be trimmed:

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[Symbai]

@danmoseley Why has this been moved to WPF repo? The WPF team has nothing to do with the trimming feature and the issue is that the trimming feature has removed assemblies it shouldn't. It should get reviewed by the developers who are responsible for the logic of the trimming feature

[danmoseley]

My assumption was that this was due to WPF assemblies not supporting trimming because they have not been annotated ie they have linker warnings.

@eerhardt thoughts?

[ThomasGoulet73]

Here is the target I use to configure trimming in my WPF application:

<Target Name="ConfigureTrimming" BeforeTargets="PrepareForILLink">
  <ItemGroup>
    <ManagedAssemblyToLink Condition="'%(Filename)' == 'System.Runtime' Or '%(Filename)' == 'System.Runtime.Extensions' Or '%(Filename)' == 'System.Diagnostics.Debug'">
      <IsTrimmable>false</IsTrimmable>
    </ManagedAssemblyToLink>
  </ItemGroup>
</Target>

You can copy/paste it in your main csproj and if you still have an exception, you can add the trimmed assembly in the condition using Or '%(Filename)' == 'NAME_OF_YOUR_ASSEMBLY'.

[ThomasGoulet73]

@danmoseley If I understood the trimming correctly, the WPF assemblies are not trimmed but the assemblies from the BCL can be trimmed. That's why the exception is for an assembly from the BCL.

[Symbai]

Thank you but that just exclude the files manually and did not explain/solve the issue that the trimming feature is working absolutely incorrectly. Except for hello world applications I've never seen trimming feature that does not crash an application and in this case its deleting base assemblies. My code uses the File class literately everywhere and still its deleting System.File.IO. My code uses WebClient a lot and still its deleting System.Net. I have async code a lot still its deleting System.Threading.Task

Why is System.Data, System.Runtime or mscorlib deleted? I've never seen a .NET app running without these. There is some serious issue in the trimming feature logic that needs to be fixed.

Only third party assemblies or some "rare edge cases" devs should be told to manually exclude them. Otherwise its not a solution

//edit: Is the trimming feature meant to support WPF? Does it understand XAML binding, MVVM patterns? I have the horrible feeling it might not but I'm hoping I'm wrong.

See my comment below

[ThomasGoulet73]

Thank you but that just exclude the files manually and did not explain/solve the issue that the trimming feature is working absolutely incorrectly. Except for hello world applications I've never seen trimming feature that does not crash an application and in this case its deleting base assemblies. My code uses the File class literately everywhere and still its deleting System.File.IO. My code uses WebClient a lot and still its deleting System.Net. I have async code a lot still its deleting System.Threading.Task

Why is System.Data, System.Runtime or mscorlib deleted? I've never seen a .NET app running without these. There is some serious issue in the trimming feature logic that needs to be fixed.

Many of the dlls in your screenshot are only facades, they do not actually contain code. The code is in other assemblies, mostly System.Private.CoreLib. You can see it for yourself by peeking inside the content of a trimmed dll with a decompiler like dotPeek.

[ThomasGoulet73]

//edit: Is the trimming feature meant to support WPF? Does it understand XAML binding, MVVM patterns? I have the horrible feeling it might not but I'm hoping I'm wrong.

I don't think it's officially supported (See the "in preview" part in the publish profile), though a WPF or .Net team member can correct me.

I can say that I didn't really have any problem with trimming except for the target that I posted.

Also, I think there is an effort to annotate the BCL and frameworks like WPF for trimming in .Net 6. See #3811. These annotations can help the linker see what is not required, even with reflection.

Edit: I had success using MVVM, Bindings, Reflection, File IO and async Code using the linker. Even with <TrimMode>link</TrimMode>.

[Symbai]

I was wrong, I apologize. After adding your code the trimmed applications works perfectly fine (as far as I can tell). So yes there is a problem with detecting these 3(?) assemblies in the trimming logic only.

[eerhardt]

This is a bug in the trimming tool. These assemblies should not be trimmed. I believe this issue should be moved to the https://github.com/mono/linker/ repo.

Another interesting fact is that if you upgrade to 6.0, the app breaks even worse because TrimMode=link is now enabled by default. The first error I am getting in 6.0 is:

System.MissingMethodException: 'Method not found: 'Void System.Runtime.InteropServices.GCHandle.set_Target(System.Object)'.'

cc @marek-safar @vitek-karas @mateoatr @sbomer

[sbomer]

This issue was moved to dotnet/linker#1917