PublishTrimmed trims too much (Could not load type 'System.Text.Json.JsonSerializer')

Steps to reproduce

• checkout https://github.com/VncDotnet/VncMatrix/tree/66fa86b446d2302ac4ae48723f8730e00dc720bd
• run dotnet publish -r win-x64 -c Debug /p:PublishSingleFile=true /p:PublishTrimmed=true --self-contained
• run the built binary: C:\Users\Benni\repositories\VncMatrix\VncMatrix\bin\Debug\netcoreapp3.0\win-x64\publish>VncMatrix.exe

Expected behavior

The program starts successfully.

Actual behavior

Note that this window only appears if you run the binary from a console - if I doubleclick it in an explorer window, the process exits without displaying that error window. Is that intended or a seperate bug? Shouldn’t it be the other way round?

Environment data

dotnet --info output:

PS C:\Users\Benni\repositories\VncMatrix\VncMatrix> dotnet --info                                                                                                                                                                                                               .NET Core SDK (gemäß "global.json"):                                                                                                                                                                                                                                             Version:   3.0.100
 Commit:    04339c3a26

Laufzeitumgebung:
 OS Name:     Windows
 OS Version:  10.0.18362
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.0.100\

Host (useful for support):
  Version: 3.0.0
  Commit:  7d57652f33

.NET Core SDKs installed:
  2.1.505 [C:\Program Files\dotnet\sdk]
  2.1.801 [C:\Program Files\dotnet\sdk]
  2.2.105 [C:\Program Files\dotnet\sdk]
  3.0.100-preview9-014004 [C:\Program Files\dotnet\sdk]
  3.0.100-rc1-014190 [C:\Program Files\dotnet\sdk]
  3.0.100 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview9.19424.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-rc1.19457.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview9-19423-09 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-rc1-19456-20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview9-19423-09 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.0.0-rc1-19456-20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

[Kinematics]

I’m having basically the same problem, but with the issue that I have no idea how to find what roots I need to include, since the failure is deep inside private WPF code.

The top of a ~90 line stack trace is:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.TypeInitializationException: The type initializer for 'MS.Internal.SystemXmlLinqExtension' threw an exception.
 ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at MS.Internal.SystemXmlLinqExtension..cctor()
   --- End of inner exception stack trace ---
   at MS.Internal.SystemXmlLinqExtension..ctor()
   --- End of inner exception stack trace ---
   at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean wrapExceptions, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& hasNoDefaultCtor)
   at System.RuntimeType.CreateInstanceDefaultCtorSlow(Boolean publicOnly, Boolean wrapExceptions, Boolean fillCache)
   at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, Boolean wrapExceptions)
   at System.Activator.CreateInstance(Type type, Boolean nonPublic, Boolean wrapExceptions)
   at System.Activator.CreateInstance(Type type)
   at MS.Internal.AssemblyHelper.LoadExtensionFor(String name)
   at MS.Internal.AssemblyHelper.ExtensionsForSystemXmlLinq(Boolean force)
   at MS.Internal.SystemXmlLinqHelper.IsXElement(Object item)

This is also an open issue in the Mono tracker (https://github.com/mono/linker/issues/712), which directed me at adding:

  <ItemGroup>
    <TrimmerRootAssembly Include="System" />
    <TrimmerRootAssembly Include="PresentationFramework-SystemXmlLinq" />
  </ItemGroup>

However that has no effect. The untrimmed version of the PresentationFramework-SystemXmlLinq.dll file is 18 KB, while the trimmed version (with or without the above directive) is 6 KB. Using dnSpy to look at the class constructor only sees GetType() reflection as anything likely to cause this problem, but making sure System.dll was included didn’t help.

Everything works fine with PublishTrimmed set to false.

Overall, between this and other bugs I’ve encountered, PublishTrimmed has been quite a headache.

[rewbot]

I’m running into a similar issue with a .NET Core 3.1 single file .exe that is using the PublishTrimmed option. When running it on a Windows 2008 R2 server (6.1.7601) I get the following error:

The type initializer for 'MS.Internal.SystemXmlLinqExtension' threw an exception.

The error does not occur when running the .exe locally on Windows 10 (Version 1909, OS build 18363.900)