ASP.NET's global.json `tool\vs` section behaves poorly

[ericstj]

I was running into a situation where I my ASP.NET build was consistently failing to find FSharp targets when building.

aspnetcore/global.json

Lines 16 to 22 in 9a6b2eb

	"version": "17.13",
	"components": [
	"Microsoft.VisualStudio.Component.VC.ATL",
	"Microsoft.VisualStudio.Component.VC.ATL.ARM64",
	"Microsoft.VisualStudio.Component.VC.Tools.ARM64",
	"Microsoft.VisualStudio.Component.VC.Tools.x86.x64"
	]

I found the root cause was my devbox (VS Client SKU) had VC, ATL, x64 and ARM64 tools. I was missing ARM64 ATL libs - apparently wasn't part of the workflows installed.

The result was that ASPNETCore build decided to not use my installed VS, but instead decided to download the Xcopy-MSBuild package, which not only was missing all the VC components but also missing FSharp targets 🙃

Seems this isn't working as expected....

[ViktorHofer]

cc @wtgodbe

[wtgodbe]

We recommend running https://github.com/dotnet/aspnetcore/blob/main/eng/scripts/InstallVisualStudio.ps1 to get the necessary tools (this is mentioned in the startup docs) - does that solve the issue?

[ViktorHofer]

This is about a VMR build...

[wtgodbe]

It still seems to be an issue w/ missing components, right? I think running that script to get aspnetcore's required components installed would still fix the issue

[wtgodbe]

@ericstj did running the script I linked above fix the issue? Wondering if I can close this. More broadly, @ViktorHofer @mmitche does the VMR have docs about how to do local dev in each repo project? I imagine it'd just be something like "Read the repo-specific docs"

[ericstj]

I no longer have a good repro of this. I think trying a fresh devbox should reproduce the issue. A few folks have reported it.

Even if running that script fixes it, you need a much better failure mode. What it does right now by silently trying to download a nuget-based MSBuild and use that is completely wrong.

Also, my build would have worked fine with my machine-wide VS as I wasn't even trying to build ARM binaries.