fix: resolve threading issues in src/VisualStudio

src/VisualStudio/Debugger.Support/RTLink/RtLink.cs

@@ -38,14 +38,16 @@ static RtLink()
         {
             AppDomain.CurrentDomain.AssemblyLoad += AssemblyLoadEventHandler;
             var loadedAssemblies = new HashSet<Assembly>(AppDomain.CurrentDomain.GetAssemblies());
-            do
+            lock (LoadedAssemblies)
             {
-                LoadedAssemblies.UnionWith(loadedAssemblies);
-                loadedAssemblies = new HashSet<Assembly>(AppDomain.CurrentDomain.GetAssemblies());
-                loadedAssemblies.RemoveWhere(a => a.IsDynamic);
-                loadedAssemblies.ExceptWith(LoadedAssemblies);
-            } while (loadedAssemblies.Count > 0);
-
+                do
+                {
+                    LoadedAssemblies.UnionWith(loadedAssemblies);
+                    loadedAssemblies = new HashSet<Assembly>(AppDomain.CurrentDomain.GetAssemblies());
+                    loadedAssemblies.RemoveWhere(a => a.IsDynamic);
+                    loadedAssemblies.ExceptWith(LoadedAssemblies);
+                } while (loadedAssemblies.Count > 0);
+            }
         }
 
 
@@ -64,7 +66,11 @@ private static void AssemblyLoadEventHandler(object sender, AssemblyLoadEventArg
         static Type FindType(string name, string asmName, out string error)
         {
             error = null;
-            var asm = LoadedAssemblies.First(a => a.FullName.ToLower().Contains(asmName.ToLower()));
+            Assembly asm;
+            lock (LoadedAssemblies)
+            {
+                asm = LoadedAssemblies.FirstOrDefault(a => a.FullName.ToLower().Contains(asmName.ToLower()));
+            }
             if (asm == null)
             {
                 error = string.Format(AssemblyNotFound, asmName);
@@ -100,8 +106,11 @@ static PropertyInfo FindProperty(this Type type, string Name, BindingFlags flags
         #endregion
         public static bool IsRTLoaded()
         {
-            return LoadedAssemblies.Any(a => a.FullName.ToLower().Contains("xsharp.rt")) &&
-                LoadedAssemblies.Any(a => a.FullName.ToLower().Contains("xsharp.core"));
+            lock (LoadedAssemblies)
+            {
+                return LoadedAssemblies.Any(a => a.FullName.ToLower().Contains("xsharp.rt")) &&
+                    LoadedAssemblies.Any(a => a.FullName.ToLower().Contains("xsharp.core"));
+            }
         }
 
         public static string GetGlobals()

src/VisualStudio/LanguageService/Classifier/XSharpClassifier.cs

@@ -62,8 +62,8 @@ public class XSharpClassifier : IClassifier
         private readonly List<String> _xtraKeywords;
         private XSharpLineState _lineState;
         private XSharpLineKeywords _lineKeywords;
-        private bool IsLexing = false;
-        private bool IsStarted = false;
+        private volatile bool IsLexing = false;
+        private volatile bool IsStarted = false;
         private bool _needsKeywords = false;
         private bool forceRepaint = false;
 

src/VisualStudio/LanguageService/XMLDoc/XSharpXMLDoc.cs

@@ -27,6 +27,7 @@ static public class XSharpXMLDocTools
         static IVsXMLMemberIndexService _XMLMemberIndexService ;
         static string coreLoc ;
         static IVsXMLMemberIndex coreIndex ;
+        static readonly object _initLock = new object();
         static XSharpXMLDocTools()
         {
             _memberIndexes = new Dictionary<string, IVsXMLMemberIndex>();
@@ -46,8 +47,12 @@ static void init()
 
         static bool GetIndex()
         {
-            if (_XMLMemberIndexService == null)
+            if (_XMLMemberIndexService != null)
+                return true;
+            lock (_initLock)
             {
+                if (_XMLMemberIndexService != null)
+                    return true;
                 ThreadHelper.JoinableTaskFactory.Run(async ( )=>
                 {
                     _XMLMemberIndexService = await VS.GetServiceAsync<SVsXMLMemberIndexService, IVsXMLMemberIndexService>();

src/VisualStudio/ProjectPackage/Commands/CommandEditProjectFile.cs

@@ -5,6 +5,7 @@
 using Microsoft.VisualStudio.Threading;
 
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -18,13 +19,14 @@ namespace XSharp.Project
     [Command(PackageIds.idEditProjectFile)]
     internal sealed class CommandEditProjectFile : BaseCommand<CommandEditProjectFile>
     {
-        static Dictionary<string, string> tempProjectFiles; // key is the project file, value is the temp file
+        static ConcurrentDictionary<string, string> tempProjectFiles; // key is the project file, value is the temp file
         static string tempProjectDir;
+        static volatile bool _eventsSubscribed = false;
         static CommandEditProjectFile()
         {
             tempProjectDir = Path.Combine(Path.GetTempPath(), "XSharp.Intellisense");
             Directory.CreateDirectory(tempProjectDir);
-            tempProjectFiles = new Dictionary<string, string>();
+            tempProjectFiles = new ConcurrentDictionary<string, string>(StringComparer.OrdinalIgnoreCase);
         }
         protected override void BeforeQueryStatus(EventArgs e)
         {
@@ -38,8 +40,14 @@ private async Task CheckAvailabilityAsync()
         protected override async Task ExecuteAsync(OleMenuCmdEventArgs e)
         {
             var project = await VS.Solutions.GetActiveProjectAsync();
-            VS.Events.DocumentEvents.Saved += DocumentEvents_Saved;
-            VS.Events.DocumentEvents.Closed += DocumentEvents_Closed;
+            // Unsubscribe before subscribing to prevent duplicate registrations
+            // if ExecuteAsync is called multiple times.
+            if (!_eventsSubscribed)
+            {
+                VS.Events.DocumentEvents.Saved += DocumentEvents_Saved;
+                VS.Events.DocumentEvents.Closed += DocumentEvents_Closed;
+                _eventsSubscribed = true;
+            }
 
 
             var projectNode = XSharpProjectNode.FindProject(project.FullPath);
@@ -82,17 +90,26 @@ private void DocumentEvents_Saved(string obj)
 
         private void DocumentEvents_Closed(string obj)
         {
+            // Find the matching key without modifying the collection during iteration.
+            string keyToRemove = null;
             foreach (var item in tempProjectFiles)
             {
-                if ( item.Value == obj)
+                if (item.Value == obj)
+                {
+                    keyToRemove = item.Key;
+                    break;
+                }
+            }
+            if (keyToRemove != null && tempProjectFiles.TryRemove(keyToRemove, out _))
+            {
+                File.Delete(obj);
+                // VS document events and commands all execute on the UI thread, so no other
+                // thread can insert a new entry between TryRemove and IsEmpty.
+                if (tempProjectFiles.IsEmpty)
                 {
-
-                    tempProjectFiles.Remove(item.Key);
                     VS.Events.DocumentEvents.Closed -= DocumentEvents_Closed;
                     VS.Events.DocumentEvents.Saved -= DocumentEvents_Saved;
-                    File.Delete(item.Value);
-                    break;
-
+                    _eventsSubscribed = false;
                 }
             }
         }

src/VisualStudio/ProjectPackage/List/ErrorList/ErrorListManager.cs

@@ -27,6 +27,7 @@ internal class ErrorListManager : ListManager<IErrorListItem>
         static ErrorListProvider _listprovider = null;
         static IErrorList _errorList = null;
         static ITableManager _manager = null;
+        static readonly object _initLock = new object();
 
 
         static ErrorListManager()
@@ -39,11 +40,16 @@ static void GetErrorList()
         {
             if (_errorList != null)
                 return;
-            _errorList = XSharpProjectPackage.XInstance.ErrorList;
-            if (_errorList != null)
+            lock (_initLock)
             {
-                _manager = _errorList.TableControl.Manager;
-                _listprovider = new ErrorListProvider(_manager);
+                if (_errorList != null)
+                    return;
+                _errorList = XSharpProjectPackage.XInstance.ErrorList;
+                if (_errorList != null)
+                {
+                    _manager = _errorList.TableControl.Manager;
+                    _listprovider = new ErrorListProvider(_manager);
+                }
             }
         }
         internal ErrorListManager(XSharpProjectNode node) : base(node)

src/VisualStudio/ProjectPackage/List/TaskList/TaskListManager.cs

@@ -28,17 +28,23 @@ internal class TaskListManager : ListManager<ITaskListItem>
         static ListProvider _listprovider = null;
         static ITaskList _taskList;
         static ITableManager _manager;
+        static readonly object _initLock = new object();
 
 
         static void GetTaskList()
         {
             if (_taskList != null)
                 return;
-            _taskList = XSharpProjectPackage.XInstance.TaskList;
-            if (_taskList != null)
+            lock (_initLock)
             {
-                _manager = _taskList.TableControl.Manager;
-                _listprovider = new TaskListProvider(_manager);
+                if (_taskList != null)
+                    return;
+                _taskList = XSharpProjectPackage.XInstance.TaskList;
+                if (_taskList != null)
+                {
+                    _manager = _taskList.TableControl.Manager;
+                    _listprovider = new TaskListProvider(_manager);
+                }
             }
         }
 

src/VisualStudio/ProjectPackage/Nodes/XSharpProjectNode.cs

@@ -51,16 +51,18 @@ public partial class XSharpProjectNode : XProjectNode, IVsSingleFileGeneratorFac
         static List<XSharpProjectNode> nodes = new List<XSharpProjectNode>();
         internal static XSharpProjectNode FindProject(string url)
         {
-            var file = System.IO.Path.GetFileName(url);
-            foreach (var proj in nodes)
+            lock (nodes)
             {
-                if (string.Compare(proj.FileName, url, true) == 0)
-                    return proj;
-                var pFile = System.IO.Path.GetFileName(proj.FileName);
-                if (string.Compare(pFile, url, true) == 0)
-                    return proj;
+                var file = System.IO.Path.GetFileName(url);
+                foreach (var proj in nodes)
+                {
+                    if (string.Compare(proj.FileName, url, true) == 0)
+                        return proj;
+                    var pFile = System.IO.Path.GetFileName(proj.FileName);
+                    if (string.Compare(pFile, url, true) == 0)
+                        return proj;
+                }
             }
-
             return null;
         }
 
@@ -86,7 +88,7 @@ static XSharpProjectNode()
             _changedProjectFiles = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
         }
         internal static IDictionary<string, string> ChangedProjectFiles => _changedProjectFiles;
-        internal static XSharpProjectNode[] AllProjects => nodes.ToArray();
+        internal static XSharpProjectNode[] AllProjects { get { lock (nodes) { return nodes.ToArray(); } } }
 
         #region Constants
         internal const string ProjectTypeName = XSharpConstants.LanguageName;