Contractual way to obtain location of MSBuild in SDK

Today, various things parse Base Path: (.*) from dotnet --info and assume they can find MSBuild there. But we have long desired to move MSBuild apart from dotnet.dll in the base path.

Perhaps we should add a separate MSBuild Base Path: (.*) to dotnet --info to be used if/when MSBuild is moved. We would then advise people to prefer MSBuild Base Path over Base Path if present.

This could also be a different invocation than dotnet --info (say `dotnet --msbuild-path), which the client would try first. But that would have the downside of requiring two dotnet invocations instead of one when resolving MSBuild from a down-level .NET Core SDK.

[rainersigwald]

The only downside of JSON is that we’d probably want to parse it with a library, and wouldn’t want to take that dependency in MSBuildLocator.

[rainersigwald]

I think for MSBuildLocator I’d prefer plain text that can be parsed simply like the initial MSBuild Base Path: proposal. No objection to additionally providing JSON for other use cases, though.

Another option would be to have a light query syntax: dotnet info MSBuildBasePath and dotnet info Version for example. That’s probably more complex than is really needed, though.