Question: return execution policy after bootstrap.cmd?

[amirebrahimi]

Describe the bug question

In Building from Source the Windows section states that you need to run:

• pre-req (in PowerShell): Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

and that bootstrap.cmd is only needed once to set up the environment to develop property. I'm not well-versed on execution policies and wondering if it would be good to return the execution policy back to what it was prior to running bootstrap.cmd? Or, is the execution policy needed to continue developing with qsharp-runtime source?

To Reproduce

Follow installation instructions for Windows

Expected behavior

A quick explanation of what this step is for since Powershell warns against it and if it is worthwhile to return back to default after (with instructions).

Actual behavior

Describe the error that you see.
If applicable, add screenshots to help explain your problem.

System information

• OS: Windows Version 10.0.18363 Build 18363
• .NET Core Version: 3.1.301

[cgranade]

Thanks for the question! The context here is that when running on Windows, execution policies are helpful to prevent accidentally running harmful code from the internet. By default, Windows PowerShell and PowerShell Core running on Windows set that policy to disable running scripts entirely. When you set your Windows installation to developer mode, or run Set-ExecutionPolicy -Scope LocalMachine -ExecutionPolicy RemoteSigned, that default changes to only allowing running scripts that came from your local computer, or that came from the internet but are signed.

The line in the README that you highlighted suggests setting the execution policy to RemoteSigned at the user-level, so that the default execution policy isn't changed for other users, and as that's the tightest level that still allows running the build scripts provided with each of the Quantum Development Kit repositories.

It's a good suggestion to clarify that a bit more in the README, thanks for raising that!