VMR Stage 2 Builds Failing in Runtime with Python not found

[Winniexu01]

Failing build in VMR (internal Microsoft link) failing in runtime with error:

/vmr/src/runtime/eng/python.targets(28,7): error : Python not found. Please add Python 3 to your path and try again. [/vmr/src/runtime/src/coreclr/System.Private.CoreLib/System.Private.CoreLib.csproj]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[Winniexu01]

The latest build is green, close the issue.

[Winniexu01]

Reopen this issue, the latest build in VMR fails.

[mthalman]

This is an odd issue. The behavior is very inconsistent. The logic which checks for Python installation hasn't been changed in a very long time. It just executes this command: command -v python3 || command -v python || command -v py. The container in which this executes definitely has Python installed and always has. The only possible explanation I have is that there is some weird MSBuild behavior where the command output isn't getting set correctly from the Exec task. /cc @rainersigwald

[mthalman]

[rainersigwald]

Almost certainly dotnet/msbuild#10378

cc @MichalPavlik

[akoeplinger]

Yes this Python not found error is what led me to filing that bug.