Fix FileNotFoundEx crash when Fold happens on untitled: scheme doc

Author: rkeithhill

src/PowerShellEditorServices.Protocol/Server/LanguageServer.cs

@@ -1376,15 +1376,24 @@ protected Task HandleEvaluateRequest(
 
         #region Event Handlers
 
-        private FoldingRange[] Fold(
-            string documentUri)
+        private FoldingRange[] Fold(string documentUri)
         {
             // TODO Should be using dynamic registrations
             if (!this.currentSettings.CodeFolding.Enable) { return null; }
+
+            // Avoid crash when using untitled: scheme or any other scheme where the document doesn't
+            // have a backing file.  https://github.com/PowerShell/vscode-powershell/issues/1676
+            // Perhaps a better option would be to parse the contents of the document as a string
+            // as opposed to reading a file but the senario of "no backing file" probably doesn't
+            // warrant the extra effort.
+            ScriptFile scriptFile = editorSession.Workspace.GetFile(documentUri);
+            if (scriptFile == null) { return null; }
+
             var result = new List<FoldingRange>();
-            foreach (FoldingReference fold in TokenOperations.FoldableRegions(
-                editorSession.Workspace.GetFile(documentUri).ScriptTokens,
-                this.currentSettings.CodeFolding.ShowLastLine))
+            FoldingReference[] foldableRegions = 
+                TokenOperations.FoldableRegions(scriptFile.ScriptTokens, this.currentSettings.CodeFolding.ShowLastLine);
+
+            foreach (FoldingReference fold in foldableRegions)
             {
                 result.Add(new FoldingRange {
                     EndCharacter   = fold.EndCharacter,
@@ -1394,6 +1403,7 @@ private FoldingRange[] Fold(
                     StartLine      = fold.StartLine
                 });
             }
+
             return result.ToArray();
         }
 

src/PowerShellEditorServices/Workspace/Workspace.cs

@@ -109,9 +109,11 @@ public ScriptFile GetFile(string filePath)
             string resolvedFilePath = this.ResolveFilePath(filePath);
             string keyName = resolvedFilePath.ToLower();
 
-            // Make sure the file isn't already loaded into the workspace
+            // Make sure the file isn't already loaded into the workspace and that the filePath isn't an "in-memory" path.
+            // There have been crashes caused by this method being called with an "untitled:" document uri. See:
+            // https://github.com/PowerShell/vscode-powershell/issues/1676
             ScriptFile scriptFile = null;
-            if (!this.workspaceFiles.TryGetValue(keyName, out scriptFile))
+            if (!this.workspaceFiles.TryGetValue(keyName, out scriptFile) && !IsPathInMemory(filePath))
             {
                 // This method allows FileNotFoundException to bubble up
                 // if the file isn't found.