Enable portable cross-arch source-building to unknown architectures.

[tmds]

The repository supports building for unknown rids to enable building for non-portable rids. This build configuration is under the '$(PortableBuild)' == 'false' condition.

This changes those conditions to '$(DotNetBuildSourceOnly)' == 'true' to enable building a portable configuration for an unknown portable rid. This configuration is used when cross-building for an architecture that is not yet known to the SDK, like linux-ppc64le or linux-s390x.

Fixes dotnet/source-build#3797.

@directhex @ViktorHofer @MichaelSimons ptal.

cc @Swapnali911 @omajid

[wtgodbe]

Assuming this was from a complete find/replace, LGTM

[directhex]

Amazing. Thanks Tom, I knew this was broken but just hadn't had a chance to look into it.

[tmds]

Assuming this was from a complete find/replace

Yes, it is.

[corngood]

This seems to have caused a regression of dotnet/source-build#3131

Previously I was able to build a source build with /p:PortableBuild=true, which caused aspnetcore to be built with /p:DotNetBuildSourceOnly=true /p:PortableBuild=true /p:TargetRuntimeIdentifier=linux-x64.

see dotnet/source-build#3131 (comment)

[tmds]

This seems to have caused a regression of dotnet/source-build#3131

I think #53528 fixed this. Do you see the issue when building the main branch?

[corngood]

I haven't tested main, but that does look like it might fix it. I'm currently trying to get 9.0.0-preview.2 building in nixpkgs. For now I've patched it to Condition=" '$(DotNetBuildSourceOnly)' == 'true' and '$(PortableBuild)' == 'false' ".

I'll test again when that change gets released. Thanks!

[tmds]

I'm curious why you need to do a portable build when building for nixpkgs?

[corngood]

It seemed to be the path of least resistance to get 8.0 working. I'll probably have to take another look at non-portable builds at some point, but:

• nixpkgs isn't an OS, so we'd need to change or bypass the /etc/os-release logic
• we need to support at least linux and darwin
• existing 'portable' packages won't actually work out of the box on nixos, and may not on other linux/darwin machines in the nix sandbox

[tmds]

I assume this means you want to provide pre-built binaries for install.

For that, you may want to set PortableBuild=true so they work across a large range of distros.
You also need to take care of the native dependencies, or the effective range of distros might be small.
For their portable builds Microsoft does it by building on an older distro.

For the nixpkgs "portable" binaries, you should still use a non-portable TargetRuntimeIdentifier that is distinct from Microsoft's.
This enables the SDK to distinguish between the nixpkgs artifacts and portable artifacts Microsoft provides through nuget.org.
That will also fix the .NET 9 previous 2 build issue you are seeing.

[corngood]

For the nixpkgs "portable" binaries, you should still use a non-portable TargetRuntimeIdentifier that is distinct from Microsoft's.

I think this might be tricky because we'd need variants for both linux and osx (and maybe bsd/windows in the future). I'll make a note to run some tests and open a more appropriate issue if I have trouble.