ARM/ARM64 not supported as values to --platform flag

[michael-hawker]

We need to build for ARM/ARM64 as platforms (as well as potentially other platforms names for different Android, iOS, etc... project types).

However, it appears that the list of values passed into the --platforms argument of the slngen tool is first scrubbed, and anything beyond x86, x64, any cpu is effectively scrubbed:

slngen/src/Microsoft.VisualStudio.SlnGen/SlnFile.cs

Lines 542 to 563 in f99e2e9

	private IEnumerable<string> GetValidSolutionPlatforms(IEnumerable<string> platforms)
	{
	List<string> values = platforms
	.Select(i => i.ToSolutionPlatform())
	.Select(platform =>
	{
	return platform.ToLowerInvariant() switch
	{
	"any cpu" => platform,
	"x64" => platform,
	"x86" => platform,
	"amd64" => "x64",
	"win32" => "x86",
	_ => null
	};
	})
	.Where(i => i != null)
	.OrderBy(i => i)
	.ToList();
	return values.Any() ? values : new List<string> { "Any CPU" };
	}

---

I assume this function is used by the slngen tool in addition to the msbuild target mode, as that's the behavior I'm seeing on the command line:

dotnet slngen --platform "ARM64"

---

This is a blocking issue for us adopting this tool in our workflow, everything else currently appears to be working fine.

The simplest solution would allow custom values by not making everything falling out of the switch statement go to null but instead pass through the original platform value.

[michael-hawker]

Here is a UWP project with a solution file showing ARM/ARM64 usage:

SettingsTest.zip

Here's an Uno project which shows other platform/configuration values:

UnoTestWASMAssemblyMetadata.zip

Don't think these are supposed to be a set list (if so that's not documented anywhere I think). They're almost like magic strings for some platforms it seems.

In either case, I think the default if a value isn't mapped it should just passthru as what was typed.

[michael-hawker]

Finally found some docs on this, wanted to post here for reference:

• https://learn.microsoft.com/en-us/visualstudio/msbuild/msbuild-target-framework-and-target-platform#target-platform (out-of-date)
• https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-options/output#platformtarget (up-to-date)