Publishing as NativeAOT should not depend on AppHost

[MichalStrehovsky]

We currently need to build apphost because for some reason PublishAot ends up needing it in some of our test legs:

runtime/eng/pipelines/runtime.yml

Line 206 in cdb9f5f

buildArgs: -s clr.runtime+clr.aot+host.native+libs -rc $(_BuildConfig) -lc Release -hc Release

Without this line, the CI fails with:

Could not copy the file "/__w/1/s/artifacts/bin/trimmingTests/projects/System.Diagnostics.DiagnosticSource.NativeAotTests/DiagnosticSourceEventSourceTests/linux-x64/obj/Release/net8.0/linux-x64/apphost" because it was not found.

This is probably not just a test issue, but also a product issue. Historically the NativeAOT targets were just an addon to the SDK targets that hacked into the SDK (we e.g. delete outputs the SDK produces in publish and replace them with NativeAOTd stuff).

The SDK probably needs to become more aware of what NativeAOT does and suppress some behaviors.

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Issue Details

---

We currently need to build apphost because for some reason PublishAot ends up needing it in some of our test legs:

runtime/eng/pipelines/runtime.yml

Line 206 in cdb9f5f

buildArgs: -s clr.runtime+clr.aot+host.native+libs -rc $(_BuildConfig) -lc Release -hc Release

Without this line, the CI fails with:

Could not copy the file "/__w/1/s/artifacts/bin/trimmingTests/projects/System.Diagnostics.DiagnosticSource.NativeAotTests/DiagnosticSourceEventSourceTests/linux-x64/obj/Release/net8.0/linux-x64/apphost" because it was not found.

This is probably not just a test issue, but also a product issue. Historically the NativeAOT targets were just an addon to the SDK targets that hacked into the SDK (we e.g. delete outputs the SDK produces in publish and replace them with NativeAOTd stuff).

The SDK probably needs to become more aware of what NativeAOT does and suppress some behaviors.

Author:	MichalStrehovsky
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	8.0.0

[ViktorHofer]

That error can be avoided by setting <UseAppHost>false</UseAppHost> but that will then raise the next error:

C:\Program Files\dotnet\sdk\7.0.100\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.RuntimeIdentifierInference.targets(186
,5): error NETSDK1067: Self-contained applications are required to use the application host. Either set SelfContained t
o false or set UseAppHost to true. [C:\temp\useaphost\useaphost.csproj]

[MichalStrehovsky]

Yeah, the SDK needs to be taught that PublishAot is sort of like self contained, but it doesn't need an apphost. I probably should have opened this in the SDK repo because the main fix will likely be in the SDK, but SDK repo is where issues typically go die of neglect and loneliness.

[ViktorHofer]

I would imagine that with the following modifications in the SDK, we should be able to publish without the apphost requirement:

• Add '$(PublishAot)' != 'true' to this condition: https://github.com/dotnet/sdk/blob/main/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets#L200-L201
• Make UseAppHost default to false when '$(PublishAot)' == 'true': https://github.com/dotnet/sdk/blob/b6898d6622ea223cbf53e6a6041803213f67f73f/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.RuntimeIdentifierInference.targets#L144

[jkotas]

Make UseAppHost default to false when '$(PublishAot)' == 'true'

We do want to keep using app host for dotnet run or F5 in Visual Studio. I do not think we want to change the global default to false when PublishAot is set.