Change debug launch handler to treat null/empty cwd to not change dir (#694)

* Change debug launch handler to treat null/empty cwd to not change dir

Fix for PowerShell/vscode-powershell#1330

Removes deprecated "Program" field from LaunchRequest class.
Simplifies working dir logic in HandleLaunchRequest.  Basically if the
launch request happens in the regular integrated console, a null/empty
cwd means "do not change the working dir".  If the request is using the
temp integrated console, there is no "existing" workng dir, so we use
the original logic to set the working dir.

* Address PR feedback, reorg to not execute working dir code unless used

* Get rid of unnecessary pragma warning disable

Author: rkeithhill

src/PowerShellEditorServices.Protocol/DebugAdapter/LaunchRequest.cs

@@ -18,12 +18,6 @@ public static readonly
 
     public class LaunchRequestArguments
     {
-        /// <summary>
-        /// Gets or sets the absolute path to the program to debug.
-        /// </summary>
-        [Obsolete("This property has been deprecated in favor of the Script property.")]
-        public string Program { get; set; }
-
         /// <summary>
         /// Gets or sets the absolute path to the script to debug.
         /// </summary>

src/PowerShellEditorServices.Protocol/Server/DebugAdapter.cs

@@ -254,55 +254,56 @@ protected async Task HandleLaunchRequest(
         {
             this.RegisterEventHandlers();
 
-            // Set the working directory for the PowerShell runspace to the cwd passed in via launch.json.
-            // In case that is null, use the the folder of the script to be executed.  If the resulting
-            // working dir path is a file path then extract the directory and use that.
-            string workingDir =
-                launchParams.Cwd ??
-                launchParams.Script ??
-#pragma warning disable 618
-                launchParams.Program;
-#pragma warning restore 618
-
-            // When debugging an "untitled" (unsaved) file - the working dir can't be derived
-            // from the Script path.  OTOH, if the launch params specifies a Cwd, use it.
-            if (ScriptFile.IsUntitledPath(workingDir) && string.IsNullOrEmpty(launchParams.Cwd))
+            // Determine whether or not the working directory should be set in the PowerShellContext.
+            if ((this.editorSession.PowerShellContext.CurrentRunspace.Location == RunspaceLocation.Local) &&
+                !this.editorSession.DebugService.IsDebuggerStopped)
             {
-                workingDir = null;
-            }
+                // Get the working directory that was passed via the debug config
+                // (either via launch.json or generated via no-config debug).
+                string workingDir = launchParams.Cwd;
 
-            if (!string.IsNullOrEmpty(workingDir))
-            {
-                workingDir = PowerShellContext.UnescapePath(workingDir);
-                try
+                // Assuming we have a non-empty/null working dir, unescape the path and verify
+                // the path exists and is a directory.
+                if (!string.IsNullOrEmpty(workingDir))
                 {
-                    if ((File.GetAttributes(workingDir) & FileAttributes.Directory) != FileAttributes.Directory)
+                    workingDir = PowerShellContext.UnescapePath(workingDir);
+                    try
                     {
-                        workingDir = Path.GetDirectoryName(workingDir);
+                        if ((File.GetAttributes(workingDir) & FileAttributes.Directory) != FileAttributes.Directory)
+                        {
+                            workingDir = Path.GetDirectoryName(workingDir);
+                        }
+                    }
+                    catch (Exception ex)
+                    {
+                        workingDir = null;
+                        Logger.Write(
+                            LogLevel.Error, 
+                            $"The specified 'cwd' path is invalid: '{launchParams.Cwd}'. Error: {ex.Message}");
                     }
                 }
-                catch (Exception ex)
-                {
-                    Logger.Write(LogLevel.Error, "cwd path is invalid: " + ex.Message);
-
-                    workingDir = null;
-                }
-            }
 
-            if (string.IsNullOrEmpty(workingDir))
-            {
+                // If we have no working dir by this point and we are running in a temp console, 
+                // pick some reasonable default.
+                if (string.IsNullOrEmpty(workingDir) && launchParams.CreateTemporaryIntegratedConsole)
+                {
 #if CoreCLR
-                workingDir = AppContext.BaseDirectory;
+                    //TODO: RKH 2018-06-26 .NET standard 2.0 has added Environment.CurrentDirectory - let's use it.
+                    workingDir = AppContext.BaseDirectory;
 #else
-                workingDir = Environment.CurrentDirectory;
+                    workingDir = Environment.CurrentDirectory;
 #endif
-            }
+                }
 
-            if (this.editorSession.PowerShellContext.CurrentRunspace.Location == RunspaceLocation.Local &&
-                !this.editorSession.DebugService.IsDebuggerStopped)
-            {
-                await editorSession.PowerShellContext.SetWorkingDirectory(workingDir, isPathAlreadyEscaped: false);
-                Logger.Write(LogLevel.Verbose, "Working dir set to: " + workingDir);
+                // At this point, we will either have a working dir that should be set to cwd in
+                // the PowerShellContext or the user has requested (via an empty/null cwd) that
+                // the working dir should not be changed.
+                if (!string.IsNullOrEmpty(workingDir))
+                {
+                    await editorSession.PowerShellContext.SetWorkingDirectory(workingDir, isPathAlreadyEscaped: false);
+                }
+
+                Logger.Write(LogLevel.Verbose, $"Working dir " + (string.IsNullOrEmpty(workingDir) ? "not set." : $"set to '{workingDir}'"));
             }
 
             // Prepare arguments to the script - if specified
@@ -315,9 +316,7 @@ protected async Task HandleLaunchRequest(
 
             // Store the launch parameters so that they can be used later
             this.noDebug = launchParams.NoDebug;
-#pragma warning disable 618
-            this.scriptToLaunch = launchParams.Script ?? launchParams.Program;
-#pragma warning restore 618
+            this.scriptToLaunch = launchParams.Script;
             this.arguments = arguments;
             this.IsUsingTempIntegratedConsole = launchParams.CreateTemporaryIntegratedConsole;