Set execution policy to Bypass when creating the initial runspace

This eliminates the need to have `SetExecutionPolicy` which is a slow function
that first queries a bunch of policies and then within PowerShell itself (as in,
using a cmdlet) sets it to `Bypass`. However, we just want the process scope
(AKA runspace scope) to have the execution policy set to `Bypass` all the time
so that we can import our bundled modules, such as PSReadLine.

Author: andyleejordan

src/PowerShellEditorServices/Services/PowerShellContext/PowerShellContextService.cs

@@ -11,6 +11,7 @@
 using System.Management.Automation.Remoting;
 using System.Management.Automation.Runspaces;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
@@ -281,6 +282,13 @@ public static Runspace CreateRunspace(PSHost psHost, PSLanguageMode languageMode
             // should have the same LanguageMode of whatever is set by the system.
             initialSessionState.LanguageMode = languageMode;
 
+            // We set the process scope's execution policy (which is really the
+            // runspace's scope) to Bypass so we can import our bundled modules.
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                initialSessionState.ExecutionPolicy = ExecutionPolicy.Bypass;
+            }
+
             Runspace runspace = RunspaceFactory.CreateRunspace(psHost, initialSessionState);
 
             // Windows PowerShell must be hosted in STA mode
@@ -408,11 +416,6 @@ public void Initialize(
             {
                 this.PromptContext = new LegacyReadLineContext(this);
             }
-
-            if (VersionUtils.IsWindows)
-            {
-                this.SetExecutionPolicy();
-            }
         }
 
         /// <summary>
@@ -2129,75 +2132,6 @@ private static string GetStringForPSCommand(PSCommand psCommand)
             return stringBuilder.ToString();
         }
 
-        private void SetExecutionPolicy()
-        {
-            this.logger.LogTrace("Setting execution policy...");
-
-            // We want to get the list hierarchy of execution policies
-            // Calling the cmdlet is the simplest way to do that
-            IReadOnlyList<PSObject> policies = this.powerShell
-                .AddCommand("Microsoft.PowerShell.Security\\Get-ExecutionPolicy")
-                    .AddParameter("-List")
-                .Invoke();
-
-            this.powerShell.Commands.Clear();
-
-            // The policies come out in the following order:
-            // - MachinePolicy
-            // - UserPolicy
-            // - Process
-            // - CurrentUser
-            // - LocalMachine
-            // We want to ignore policy settings, since we'll already have those anyway.
-            // Then we need to look at the CurrentUser setting, and then the LocalMachine setting.
-            //
-            // Get-ExecutionPolicy -List emits PSObjects with Scope and ExecutionPolicy note properties
-            // set to expected values, so we must sift through those.
-
-            ExecutionPolicy policyToSet = ExecutionPolicy.Bypass;
-            var currentUserPolicy = (ExecutionPolicy)policies[policies.Count - 2].Members["ExecutionPolicy"].Value;
-            if (currentUserPolicy != ExecutionPolicy.Undefined)
-            {
-                policyToSet = currentUserPolicy;
-            }
-            else
-            {
-                var localMachinePolicy = (ExecutionPolicy)policies[policies.Count - 1].Members["ExecutionPolicy"].Value;
-                if (localMachinePolicy != ExecutionPolicy.Undefined)
-                {
-                    policyToSet = localMachinePolicy;
-                }
-            }
-
-            // If there's nothing to do, save ourselves a PowerShell invocation
-            if (policyToSet == ExecutionPolicy.Bypass)
-            {
-                this.logger.LogTrace("Execution policy already set to Bypass. Skipping execution policy set");
-                return;
-            }
-
-            // Finally set the inherited execution policy
-            this.logger.LogTrace($"Setting execution policy to {policyToSet}");
-            try
-            {
-                this.powerShell
-                    .AddCommand("Microsoft.PowerShell.Security\\Set-ExecutionPolicy")
-                    .AddParameter("Scope", ExecutionPolicyScope.Process)
-                    .AddParameter("ExecutionPolicy", policyToSet)
-                    .AddParameter("Force")
-                    .Invoke();
-            }
-            catch (CmdletInvocationException e)
-            {
-                this.logger.LogHandledException(
-                    $"Error occurred calling 'Set-ExecutionPolicy -Scope Process -ExecutionPolicy {policyToSet} -Force'", e);
-            }
-            finally
-            {
-                this.powerShell.Commands.Clear();
-            }
-        }
-
         private SessionDetails GetSessionDetails(Func<PSCommand, PSObject> invokeAction)
         {
             try

test/PowerShellEditorServices.Test/Session/PowerShellContextTests.cs

@@ -147,10 +147,9 @@ await this.powerShellContext.ExecuteCommandAsync<string>(
         }
 
         [Trait("Category", "PSReadLine")]
-        [SkippableFact]
+        [Fact]
         public void CanGetPSReadLineProxy()
         {
-            Skip.If(IsWindows, "This test doesn't work on Windows for some reason.");
             Assert.True(PSReadLinePromptContext.TryGetPSReadLineProxy(
                 NullLogger.Instance,
                 PowerShellContextFactory.initialRunspace,