initial support of constrainedlanguage mode

Author: TylerLeonhardt

src/PowerShellEditorServices.Hosting/Commands/StartEditorServicesCommand.cs

@@ -11,6 +11,7 @@
 using System.Management.Automation;
 using System.Reflection;
 using SMA = System.Management.Automation;
+using System.Management.Automation.Runspaces;
 using Microsoft.PowerShell.EditorServices.Hosting;
 using System.Globalization;
 using System.Collections;
@@ -358,6 +359,7 @@ private EditorServicesConfig CreateConfigObject()
                 AdditionalModules = AdditionalModules,
                 LanguageServiceTransport = GetLanguageServiceTransport(),
                 DebugServiceTransport = GetDebugServiceTransport(),
+                LanguageMode = Runspace.DefaultRunspace.SessionStateProxy.LanguageMode,
                 ProfilePaths = new ProfilePathConfig
                 {
                     AllUsersAllHosts = GetProfilePathFromProfileObject(profile, ProfileUserKind.AllUsers, ProfileHostKind.AllHosts),

src/PowerShellEditorServices.Hosting/Configuration/EditorServicesConfig.cs

@@ -4,6 +4,7 @@
 //
 
 using System.Collections.Generic;
+using System.Management.Automation;
 using System.Management.Automation.Host;
 
 namespace Microsoft.PowerShell.EditorServices.Hosting
@@ -111,6 +112,11 @@ public EditorServicesConfig(
         /// </summary>
         public ProfilePathConfig ProfilePaths { get; set; }
 
+        /// <summary>
+        /// The language mode of the original runspace that we will inherit from.
+        /// </summary>
+        public PSLanguageMode LanguageMode { get; internal set; }
+
         public string StartupBanner { get; set; } = @"
 
                   =====> PowerShell Integrated Console <=====

src/PowerShellEditorServices.Hosting/EditorServicesLoader.cs

@@ -190,8 +190,6 @@ public Task LoadAndRunEditorServicesAsync()
             // Make sure the .NET Framework version supports .NET Standard 2.0
             CheckNetFxVersion();
 #endif
-            // Ensure the language mode allows us to run
-            CheckLanguageMode();
 
             // Add the bundled modules to the PSModulePath
             UpdatePSModulePath();
@@ -250,19 +248,6 @@ private void CheckNetFxVersion()
         }
 #endif
 
-        /// <summary>
-        /// PSES currently does not work in Constrained Language Mode, because PSReadLine script invocations won't work in it.
-        /// Ideally we can find a better way so that PSES will work in CLM.
-        /// </summary>
-        private void CheckLanguageMode()
-        {
-            _logger.Log(PsesLogLevel.Diagnostic, "Checking that PSES is running in FullLanguage mode");
-            if (Runspace.DefaultRunspace.SessionStateProxy.LanguageMode != PSLanguageMode.FullLanguage)
-            {
-                throw new InvalidOperationException("Cannot start PowerShell Editor Services in Constrained Language Mode");
-            }
-        }
-
         private void UpdatePSModulePath()
         {
             if (string.IsNullOrEmpty(_hostConfig.BundledModulePath))

src/PowerShellEditorServices.Hosting/Internal/EditorServicesRunner.cs

@@ -238,6 +238,7 @@ private HostStartupInfo CreateHostStartupInfo()
                 _config.FeatureFlags,
                 _config.AdditionalModules,
                 _config.LogPath,
+                _config.LanguageMode,
                 (int)_config.LogLevel,
                 consoleReplEnabled: _config.ConsoleRepl != ConsoleReplKind.None,
                 usesLegacyReadLine: _config.ConsoleRepl == ConsoleReplKind.LegacyReadLine);

src/PowerShellEditorServices/Hosting/HostStartupInfo.cs

@@ -5,6 +5,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Management.Automation;
 using System.Management.Automation.Host;
 
 namespace Microsoft.PowerShell.EditorServices.Hosting
@@ -89,6 +90,11 @@ public sealed class HostStartupInfo
         /// </summary>
         public string LogPath { get; }
 
+        /// <summary>
+        /// The language mode of the original runspace that we will inherit from.
+        /// </summary>
+        public PSLanguageMode LanguageMode { get; }
+
         /// <summary>
         /// The minimum log level of log events to be logged.
         /// </summary>
@@ -130,6 +136,7 @@ public HostStartupInfo(
             IReadOnlyList<string> featureFlags,
             IReadOnlyList<string> additionalModules,
             string logPath,
+            PSLanguageMode languageMode,
             int logLevel,
             bool consoleReplEnabled,
             bool usesLegacyReadLine)
@@ -142,6 +149,7 @@ public HostStartupInfo(
             FeatureFlags = featureFlags ?? Array.Empty<string>();
             AdditionalModules = additionalModules ?? Array.Empty<string>();
             LogPath = logPath;
+            LanguageMode = languageMode;
             LogLevel = logLevel;
             ConsoleReplEnabled = consoleReplEnabled;
             UsesLegacyReadLine = usesLegacyReadLine;

src/PowerShellEditorServices/Services/PowerShellContext/PowerShellContextService.cs

@@ -213,7 +213,7 @@ public static PowerShellContextService Create(
                     hostUserInterface,
                     logger);
 
-            Runspace initialRunspace = PowerShellContextService.CreateRunspace(psHost);
+            Runspace initialRunspace = PowerShellContextService.CreateRunspace(psHost, hostStartupInfo.LanguageMode);
             powerShellContext.Initialize(hostStartupInfo.ProfilePaths, initialRunspace, true, hostUserInterface);
 
             powerShellContext.ImportCommandsModuleAsync();
@@ -260,15 +260,15 @@ public static Runspace CreateRunspace(
             var psHost = new EditorServicesPSHost(powerShellContext, hostDetails, hostUserInterface, logger);
             powerShellContext.ConsoleWriter = hostUserInterface;
             powerShellContext.ConsoleReader = hostUserInterface;
-            return CreateRunspace(psHost);
+            return CreateRunspace(psHost, hostDetails.LanguageMode);
         }
 
         /// <summary>
         ///
         /// </summary>
         /// <param name="psHost"></param>
         /// <returns></returns>
-        public static Runspace CreateRunspace(PSHost psHost)
+        public static Runspace CreateRunspace(PSHost psHost, PSLanguageMode languageMode)
         {
             InitialSessionState initialSessionState;
             if (Environment.GetEnvironmentVariable("PSES_TEST_USE_CREATE_DEFAULT") == "1") {
@@ -277,6 +277,10 @@ public static Runspace CreateRunspace(PSHost psHost)
                 initialSessionState = InitialSessionState.CreateDefault2();
             }
 
+            // Create and initialize a new Runspace while honoring the LanguageMode.
+            Console.WriteLine(languageMode);
+            initialSessionState.LanguageMode = languageMode;
+
             Runspace runspace = RunspaceFactory.CreateRunspace(psHost, initialSessionState);
 
             // Windows PowerShell must be hosted in STA mode

test/PowerShellEditorServices.Test/PowerShellContextFactory.cs

@@ -12,6 +12,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Management.Automation;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -46,6 +47,7 @@ public static PowerShellContextService Create(ILogger logger)
                 new List<string>(),
                 new List<string>(),
                 null,
+                PSLanguageMode.FullLanguage,
                 0,
                 consoleReplEnabled: false,
                 usesLegacyReadLine: false);