Finish PowerShell v3 and v4 support

src/PowerShellEditorServices.Protocol/Server/DebugAdapter.cs

@@ -295,7 +295,14 @@ protected Task HandlePauseRequest(
             object pauseParams,
             RequestContext<object> requestContext)
         {
-            editorSession.DebugService.Break();
+            try
+            {
+                editorSession.DebugService.Break();
+            }
+            catch (NotSupportedException e)
+            {
+                return requestContext.SendError(e.Message);
+            }
 
             // This request is responded to by sending the "stopped" event
             return Task.FromResult(true);

src/PowerShellEditorServices/PowerShellEditorServices.csproj

@@ -98,8 +98,12 @@
     <Compile Include="Console\ChoiceDetails.cs" />
     <Compile Include="Session\EditorSession.cs" />
     <Compile Include="Console\IConsoleHost.cs" />
+    <Compile Include="Session\IVersionSpecificOperations.cs" />
     <Compile Include="Session\OutputType.cs" />
     <Compile Include="Session\OutputWrittenEventArgs.cs" />
+    <Compile Include="Session\PowerShell3Operations.cs" />
+    <Compile Include="Session\PowerShell4Operations.cs" />
+    <Compile Include="Session\PowerShell5Operations.cs" />
     <Compile Include="Session\PowerShellExecutionResult.cs" />
     <Compile Include="Session\PowerShellContext.cs" />
     <Compile Include="Session\PowerShellContextState.cs" />

src/PowerShellEditorServices/Session/EditorSession.cs

@@ -5,9 +5,11 @@
 
 using Microsoft.PowerShell.EditorServices.Console;
 using Microsoft.PowerShell.EditorServices.Utility;
+using System;
 using System.IO;
 using System.Management.Automation;
 using System.Management.Automation.Runspaces;
+using System.Reflection;
 using System.Threading;
 
 namespace Microsoft.PowerShell.EditorServices
@@ -66,17 +68,34 @@ public void StartSession()
             this.DebugService = new DebugService(this.PowerShellContext);
             this.ConsoleService = new ConsoleService(this.PowerShellContext);
 
-            // AnalysisService will throw FileNotFoundException if
-            // Script Analyzer binaries are not included.
-            try
+            // Only enable the AnalysisService if the machine has PowerShell
+            // v5 installed.  Script Analyzer works on earlier PowerShell
+            // versions but our hard dependency on their binaries complicates
+            // the deployment and assembly loading since we would have to
+            // conditionally load the binaries for v3/v4 support.  This problem
+            // will be solved in the future by using Script Analyzer as a
+            // module rather than an assembly dependency.
+            if (this.PowerShellContext.PowerShellVersion.Major >= 5)
             {
-                this.AnalysisService = new AnalysisService();
+                // AnalysisService will throw FileNotFoundException if
+                // Script Analyzer binaries are not included.
+                try
+                {
+                    this.AnalysisService = new AnalysisService();
+                }
+                catch (FileNotFoundException)
+                {
+                    Logger.Write(
+                        LogLevel.Warning,
+                        "Script Analyzer binaries not found, AnalysisService will be disabled.");
+                }
             }
-            catch (FileNotFoundException)
+            else
             {
                 Logger.Write(
-                    LogLevel.Warning,
-                    "Script Analyzer binaries not found, AnalysisService will be disabled.");
+                    LogLevel.Normal,
+                    "Script Analyzer cannot be loaded due to unsupported PowerShell version " +
+                    this.PowerShellContext.PowerShellVersion.ToString());
             }
 
             // Create a workspace to contain open files

src/PowerShellEditorServices/Session/IVersionSpecificOperations.cs

@@ -0,0 +1,25 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+using System.Management.Automation;
+using System.Management.Automation.Runspaces;
+
+namespace Microsoft.PowerShell.EditorServices.Session
+{
+    internal interface IVersionSpecificOperations
+    {
+        void ConfigureDebugger(Runspace runspace);
+
+        void PauseDebugger(Runspace runspace);
+
+        IEnumerable<TResult> ExecuteCommandInDebugger<TResult>(
+            PowerShellContext powerShellContext,
+            Runspace currentRunspace,
+            PSCommand psCommand,
+            bool sendOutputToHost);
+    }
+}
+

src/PowerShellEditorServices/Session/PowerShell3Operations.cs

@@ -0,0 +1,62 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Management.Automation;
+using System.Management.Automation.Runspaces;
+
+namespace Microsoft.PowerShell.EditorServices.Session
+{
+    internal class PowerShell3Operations : IVersionSpecificOperations
+    {
+        public void ConfigureDebugger(Runspace runspace)
+        {
+            // The debugger has no SetDebugMode in PowerShell v3.
+        }
+
+        public void PauseDebugger(Runspace runspace)
+        {
+            // The debugger cannot be paused in PowerShell v3.
+            throw new NotSupportedException("Debugger cannot be paused in PowerShell v3");
+        }
+
+        public IEnumerable<TResult> ExecuteCommandInDebugger<TResult>(
+            PowerShellContext powerShellContext,
+            Runspace currentRunspace,
+            PSCommand psCommand,
+            bool sendOutputToHost)
+        {
+            IEnumerable<TResult> executionResult = null;
+
+            using (var nestedPipeline = currentRunspace.CreateNestedPipeline())
+            {
+                foreach (var command in psCommand.Commands)
+                {
+                    nestedPipeline.Commands.Add(command);
+                }
+
+                executionResult =
+                    nestedPipeline
+                        .Invoke()
+                        .Select(pso => pso.BaseObject)
+                        .Cast<TResult>();
+            }
+
+            // Write the output to the host if necessary
+            if (sendOutputToHost)
+            {
+                foreach (var line in executionResult)
+                {
+                    powerShellContext.WriteOutput(line.ToString(), true);
+                }
+            }
+
+            return executionResult;
+        }
+    }
+}
+

src/PowerShellEditorServices/Session/PowerShell4Operations.cs

@@ -0,0 +1,65 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Management.Automation;
+using System.Management.Automation.Runspaces;
+
+namespace Microsoft.PowerShell.EditorServices.Session
+{
+    internal class PowerShell4Operations : IVersionSpecificOperations
+    {
+        public void ConfigureDebugger(Runspace runspace)
+        {
+#if !PowerShellv3
+            runspace.Debugger.SetDebugMode(DebugModes.LocalScript | DebugModes.RemoteScript);
+#endif
+        }
+
+        public virtual void PauseDebugger(Runspace runspace)
+        {
+            // The debugger cannot be paused in PowerShell v4.
+            throw new NotSupportedException("Debugger cannot be paused in PowerShell v4");
+        }
+
+        public IEnumerable<TResult> ExecuteCommandInDebugger<TResult>(
+            PowerShellContext powerShellContext,
+            Runspace currentRunspace,
+            PSCommand psCommand,
+            bool sendOutputToHost)
+        {
+            PSDataCollection<PSObject> outputCollection = new PSDataCollection<PSObject>();
+
+#if !PowerShellv3
+            if (sendOutputToHost)
+            {
+                outputCollection.DataAdded +=
+                    (obj, e) =>
+                    {
+                        for (int i = e.Index; i < outputCollection.Count; i++)
+                        {
+                            powerShellContext.WriteOutput(
+                                outputCollection[i].ToString(),
+                                true);
+                        }
+                    };
+            }
+
+            DebuggerCommandResults commandResults =
+                currentRunspace.Debugger.ProcessCommand(
+                    psCommand,
+                    outputCollection);
+#endif
+
+            return
+                outputCollection
+                    .Select(pso => pso.BaseObject)
+                    .Cast<TResult>();
+        }
+    }
+}
+

src/PowerShellEditorServices/Session/PowerShell5Operations.cs

@@ -0,0 +1,20 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Management.Automation.Runspaces;
+
+namespace Microsoft.PowerShell.EditorServices.Session
+{
+    internal class PowerShell5Operations : PowerShell4Operations
+    {
+        public override void PauseDebugger(Runspace runspace)
+        {
+#if !PowerShellv3 && !PowerShellv4
+            runspace.Debugger.SetDebuggerStepMode(true);
+#endif
+        }
+    }
+}
+