When compiling Blazor Hybrid app with NativeAOT, can't root System.Action generic

[jaedan]

Description

I've built a simple WinForms application with a single BlazorWebView and I'm compiling it with NativeAOT. This repo contains code that reproduces the issue: https://github.com/jaedan/WinFormsBlazorHybridAOT/
(Additionally, I've repeated this same example using Photino instead of WinForms here: https://github.com/jaedan/Photino.Blazor.Native and I get the same result)

The applications compile and produce a binary. But when a razor page makes a call back to the main c# code (which triggers the message passing) then the application crashes because it is missing this type:

System.Action`2[Microsoft.AspNetCore.Components.Routing.Router, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]

I can't find any way to get that type into rd.xml that actually works. I've tried this:

<Assembly Name="System.Private.CoreLib">
  <Type Name="System.Action`2[Microsoft.AspNetCore.Components.Routing.Router, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]" Dynamic="Required All" />
</Assembly>

And that fails as follows:

 Failed to load type 'Microsoft.AspNetCore.Components.Routing.Router' from assembly 'System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'

I've changed the assembly name to Microsoft.AspNetCore.Components, but that just changes it so that it fails to load System.Action instead.

Reproduction Steps

To get crash notifying of missing runtime type:

• Clone https://github.com/jaedan/WinFormsBlazorHybridAOT/
• dotnet publish -r win-x64 --self-contained
• Run executable

To get rd.xml problems:

• Modify rd.xml in the repo to add

    <Assembly Name="System.Private.CoreLib">
      <Type Name="System.Action`2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]" Dynamic="Required All" />
    </Assembly>

• dotnet publish -r win-x64 --self-contained

Expected behavior

Need to somehow root System.Action2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback1[Microsoft.AspNetCore.Components.Routing.NavigationContext]] so it stops getting trimmed.

Actual behavior

System.Action2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback1[Microsoft.AspNetCore.Components.Routing.NavigationContext]] gets trimmed

Regression?

I doubt anyone has ever tried this before.

Known Workarounds

Don't use NativeAOT

Configuration

• .net 7
• Win11
• x64
• Probably not specific to a configuration
• It's WebView2, so Edge.

Other information

Maybe this is related to #72833? It seems to me like it's trying to resolve the nested types within the parent assembly, but they're clearly in a different assembly so that behavior isn't correct. I'd love to be able to just root types more directly, without putting everything in an <Assembly> tag.

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Issue Details

---

Description

I've built a simple WinForms application with a single BlazorWebView and I'm compiling it with NativeAOT. This repo contains code that reproduces the issue: https://github.com/jaedan/WinFormsBlazorHybridAOT/
(Additionally, I've repeated this same example using Photino instead of WinForms here: https://github.com/jaedan/Photino.Blazor.Native and I get the same result)

The applications compile and produce a binary. But when a razor page makes a call back to the main c# code (which triggers the message passing) then the application crashes because it is missing this type:

System.Action`2[Microsoft.AspNetCore.Components.Routing.Router, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]

I can't find any way to get that type into rd.xml that actually works. I've tried this:

<Assembly Name="System.Private.CoreLib">
  <Type Name="System.Action`2[Microsoft.AspNetCore.Components.Routing.Router, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]" Dynamic="Required All" />
</Assembly>

And that fails as follows:

 Failed to load type 'Microsoft.AspNetCore.Components.Routing.Router' from assembly 'System.Private.CoreLib, Version=7.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'

I've changed the assembly name to Microsoft.AspNetCore.Components, but that just changes it so that it fails to load System.Action instead.

Reproduction Steps

To get crash notifying of missing runtime type:

• Clone https://github.com/jaedan/WinFormsBlazorHybridAOT/
• dotnet publish -r win-x64 --self-contained
• Run executable

To get rd.xml problems:

• Modify rd.xml in the repo to add

    <Assembly Name="System.Private.CoreLib">
      <Type Name="System.Action`2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]" Dynamic="Required All" />
    </Assembly>

• dotnet publish -r win-x64 --self-contained

Expected behavior

Need to somehow root System.Action2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback1[Microsoft.AspNetCore.Components.Routing.NavigationContext]] so it stops getting trimmed.

Actual behavior

System.Action2[Microsoft.AspNetCore.Components, Microsoft.AspNetCore.Components.EventCallback1[Microsoft.AspNetCore.Components.Routing.NavigationContext]] gets trimmed

Regression?

I doubt anyone has ever tried this before.

Known Workarounds

Don't use NativeAOT

Configuration

• .net 7
• Win11
• x64
• Probably not specific to a configuration
• It's WebView2, so Edge.

Other information

Maybe this is related to #72833? It seems to me like it's trying to resolve the nested types within the parent assembly, but they're clearly in a different assembly so that behavior isn't correct. I'd love to be able to just root types more directly, without putting everything in an <Assembly> tag.

Author:	jaedan
Assignees:	-
Labels:	untriaged, area-NativeAOT-coreclr
Milestone:	-

[kant2002]

I think that's related to dotnet/aspnetcore#45580 basically it's issue with how ASP.NET Core code is structure.

you have small issue in original rd.xml

<Assembly Name="System.Private.CoreLib">
  <Type Name="System.Action`2[[Microsoft.AspNetCore.Components.Routing.Router,Microsoft.AspNetCore.Components],[Microsoft.AspNetCore.Components.EventCallback`1[[Microsoft.AspNetCore.Components.Routing.NavigationContext,Microsoft.AspNetCore.Components]],Microsoft.AspNetCore.Components]]" Dynamic="Required All" />
</Assembly>

Notice that because Microsoft.AspNetCore.Components.Routing.Router is in different assembly then System.Private.CoreLib, you need specify assembly name when reference type name. Don't forget wrap in []. So

before

Microsoft.AspNetCore.Components.Routing.Router

after

[Microsoft.AspNetCore.Components.Routing.Router, Microsoft.AspNetCore.Components]

I think you can simplify rd.xml by just writing declaration like this

<Assembly Name="Microsoft.AspNetCore.Components">
  <Type Name="Microsoft.AspNetCore.Components.Routing.Router" Dynamic="Required All" />
  <Type Name="Microsoft.AspNetCore.Components.EventCallback`1[Microsoft.AspNetCore.Components.Routing.NavigationContext]]" Dynamic="Required All" />
</Assembly>

it's quite possible that you need to root just one class, because others are already detected. I can only recommend guessing here.

[jaedan]

Ok, I understand now how to get the rd.xml to find the types and that seems to be working. It doesn't fix the problems - I still get errors that MethodInfo.MakeGenericMethod() is not compatible with AOT compilation, and this must be related to the issue you posted. I think we can close this one and just track it in that issue instead.

Thanks for the help!