DOTNET_INSTALL_DIR is corrupted if there are multiple dotnet CLI installs on the path

[analogrelay]

If the user has multiple dotnet CLIs on their path, the DOTNET_INSTALL_DIR value gets corrupted because this code doesn't properly select the first result:

https://github.com/dotnet/arcade-minimalci-sample/blob/a249ce8e79a9b71d5367d7bc59132121a7490d5b/eng/common/tools.ps1#L36-L38

On my machine, where the PATH search yields multiple results, DOTNET_INSTALL_DIR ends up being set to multiple directories:

This causes the search for the correct SDK version to fail, and Arcade changes to use a repo-local .dotnet directory, which is definitely not what I wanted :).

A simple patch to add | select -first 1 on the end fixes this for PowerShell. Haven't checked if this occurs in Bash as well.

[alexperovich]

That code is a bit odd. Why is it not just (Get-Command dotnet.exe).Path on windows and command -v dotnet on linux?

[markwilkie]

@anurse - thoughts on @alexperovich comment?

[analogrelay]

Sounds fine to me. I just want the script to find dotnet even when I have multiple on the PATH :)

[markwilkie]

The solution to #1253 likely makes this better.

[analogrelay]

Ping @chcosta @natemcmaster

[tmat]

I'll have a fix soon.