Cancelling static graph-based restore does not end the restore process

[jeffkl]

NuGet Product Used

MSBuild.exe, dotnet.exe

Product Version

All

Worked before?

No response

Impact

It bothers me. A fix would be nice

Repro Steps & Context

Static graph-based restore launches an external process and waits for it to return:

https://github.com/NuGet/NuGet.Client/blob/dev/src/NuGet.Core/NuGet.Build.Tasks/StaticGraphRestoreTaskBase.cs#L184

However, the code passes a cancellation token which is fired when the user cancels a build via CTRL+C. The catch code is there to return true so that cancelled builds don't "fail" but it does not kill the process.

https://github.com/NuGet/NuGet.Client/blob/dev/src/NuGet.Core/NuGet.Build.Tasks/StaticGraphRestoreTaskBase.cs#L211-L217

The try...catch which handles cancellation should be moved to surround just the Semaphore.Wait() since that's the only call that would throw an OperationCanceledException. The proceeding code would then kill the process and return true in the case where the user canceled the build.

Verbose Logs

No response