polish ConstrainedLanguage mode

module/PowerShellEditorServices/Commands/Public/Clear-Host.ps1

@@ -10,7 +10,9 @@ function Clear-Host {
     param()
 
     __clearhost
-    $psEditor.Window.Terminal.Clear()
+    if ($host.Runspace.LanguageMode -eq [System.Management.Automation.PSLanguageMode]::FullLanguage) {
+        $psEditor.Window.Terminal.Clear()
+    }
 }
 
 if (!$IsMacOS -or $IsLinux) {

src/PowerShellEditorServices.Hosting/Configuration/EditorServicesConfig.cs

@@ -113,7 +113,8 @@ public EditorServicesConfig(
         public ProfilePathConfig ProfilePaths { get; set; }
 
         /// <summary>
-        /// The language mode of the original runspace that we will inherit from.
+        /// The language mode inherited from the orginal PowerShell process.
+        /// This will be used when creating runspaces so that we honor the same language mode.
         /// </summary>
         public PSLanguageMode LanguageMode { get; internal set; }
 

src/PowerShellEditorServices.Hosting/Internal/EditorServicesRunner.cs

@@ -237,8 +237,8 @@ private HostStartupInfo CreateHostStartupInfo()
                 profilePaths,
                 _config.FeatureFlags,
                 _config.AdditionalModules,
-                _config.LogPath,
                 _config.LanguageMode,
+                _config.LogPath,
                 (int)_config.LogLevel,
                 consoleReplEnabled: _config.ConsoleRepl != ConsoleReplKind.None,
                 usesLegacyReadLine: _config.ConsoleRepl == ConsoleReplKind.LegacyReadLine);

src/PowerShellEditorServices/Hosting/HostStartupInfo.cs

@@ -91,7 +91,8 @@ public sealed class HostStartupInfo
         public string LogPath { get; }
 
         /// <summary>
-        /// The language mode of the original runspace that we will inherit from.
+        /// The language mode inherited from the orginal PowerShell process.
+        /// This will be used when creating runspaces so that we honor the same language mode.
         /// </summary>
         public PSLanguageMode LanguageMode { get; }
 
@@ -123,6 +124,7 @@ public sealed class HostStartupInfo
         /// <param name="currentUsersProfilePath">The path to the user specific profile.</param>
         /// <param name="featureFlags">Flags of features to enable.</param>
         /// <param name="additionalModules">Names or paths of additional modules to import.</param>
+        /// <param name="languageMode">The language mode inherited from the orginal PowerShell process. This will be used when creating runspaces so that we honor the same language mode.</param>
         /// <param name="logPath">The path to log to.</param>
         /// <param name="logLevel">The minimum log event level.</param>
         /// <param name="consoleReplEnabled">Enable console if true.</param>
@@ -135,8 +137,8 @@ public HostStartupInfo(
             ProfilePathInfo profilePaths,
             IReadOnlyList<string> featureFlags,
             IReadOnlyList<string> additionalModules,
-            string logPath,
             PSLanguageMode languageMode,
+            string logPath,
             int logLevel,
             bool consoleReplEnabled,
             bool usesLegacyReadLine)
@@ -148,8 +150,8 @@ public HostStartupInfo(
             ProfilePaths = profilePaths;
             FeatureFlags = featureFlags ?? Array.Empty<string>();
             AdditionalModules = additionalModules ?? Array.Empty<string>();
-            LogPath = logPath;
             LanguageMode = languageMode;
+            LogPath = logPath;
             LogLevel = logLevel;
             ConsoleReplEnabled = consoleReplEnabled;
             UsesLegacyReadLine = usesLegacyReadLine;

src/PowerShellEditorServices/Services/PowerShellContext/PowerShellContextService.cs

@@ -244,9 +244,7 @@ public static PowerShellContextService Create(
         /// </summary>
         /// <param name="hostDetails"></param>
         /// <param name="powerShellContext"></param>
-        /// <param name="hostUserInterface">
-        /// The EditorServicesPSHostUserInterface to use for this instance.
-        /// </param>
+        /// <param name="hostUserInterface">The EditorServicesPSHostUserInterface to use for this instance.</param>
         /// <param name="logger">An ILogger implementation to use for this instance.</param>
         /// <returns></returns>
         public static Runspace CreateRunspace(
@@ -266,7 +264,8 @@ public static Runspace CreateRunspace(
         /// <summary>
         ///
         /// </summary>
-        /// <param name="psHost"></param>
+        /// <param name="psHost">The PSHost that will be used for this Runspace.</param>
+        /// <param name="languageMode">The language mode inherited from the orginal PowerShell process. This will be used when creating runspaces so that we honor the same language mode.</param>
         /// <returns></returns>
         public static Runspace CreateRunspace(PSHost psHost, PSLanguageMode languageMode)
         {
@@ -277,8 +276,9 @@ public static Runspace CreateRunspace(PSHost psHost, PSLanguageMode languageMode
                 initialSessionState = InitialSessionState.CreateDefault2();
             }
 
-            // Create and initialize a new Runspace while honoring the LanguageMode.
-            Console.WriteLine(languageMode);
+            // Create and initialize a new Runspace while honoring the LanguageMode of the original runspace
+            // that started PowerShell Editor Services. This is because the PowerShell Integrated Console
+            // should have the same LanguageMode of whatever is set by the system.
             initialSessionState.LanguageMode = languageMode;
 
             Runspace runspace = RunspaceFactory.CreateRunspace(psHost, initialSessionState);
@@ -414,6 +414,8 @@ public void Initialize(
 
             if (powerShellVersion.Major >= 5 &&
                 this.isPSReadLineEnabled &&
+                // TODO: Figure out why PSReadLine isn't working in ConstrainedLanguage mode.
+                initialRunspace.SessionStateProxy.LanguageMode == PSLanguageMode.FullLanguage &&
                 PSReadLinePromptContext.TryGetPSReadLineProxy(logger, initialRunspace, out PSReadLineProxy proxy))
             {
                 this.PromptContext = new PSReadLinePromptContext(

test/PowerShellEditorServices.Test/PowerShellContextFactory.cs

@@ -46,8 +46,8 @@ public static PowerShellContextService Create(ILogger logger)
                 TestProfilePaths,
                 new List<string>(),
                 new List<string>(),
-                null,
                 PSLanguageMode.FullLanguage,
+                null,
                 0,
                 consoleReplEnabled: false,
                 usesLegacyReadLine: false);