Merge pull request #13934 from jasonmalinowski/fix-option-race

Fix option race causing crashes

src/Workspaces/Core/Portable/Options/GlobalOptionService.cs

@@ -143,6 +143,17 @@ public void RefreshOption(OptionKey optionKey, object newValue)
         {
             lock (_gate)
             {
+                object oldValue;
+
+                if (_currentValues.TryGetValue(optionKey, out oldValue))
+                {
+                    if (object.Equals(oldValue, newValue))
+                    {
+                        // Value is still the same, no reason to raise events
+                        return;
+                    }
+                }
+
                 _currentValues = _currentValues.SetItem(optionKey, newValue);
             }
 

src/Workspaces/Core/Portable/Options/OptionServiceFactory.cs

@@ -65,17 +65,16 @@ public void OnWorkspaceDisposed(Workspace workspace)
 
             private void OnGlobalOptionServiceOptionChanged(object sender, OptionChangedEventArgs e)
             {
-                var eventHandlers = GetEventHandlers();
-                if (eventHandlers.Length > 0)
+                _taskQueue?.ScheduleTask(() =>
                 {
-                    _taskQueue?.ScheduleTask(() =>
+                    // Ensure we grab the event handlers inside the scheduled task to prevent a race of people unsubscribing
+                    // but getting the event later on the UI thread
+                    var eventHandlers = GetEventHandlers();
+                    foreach (var handler in eventHandlers)
                     {
-                        foreach (var handler in eventHandlers)
-                        {
-                            handler(this, e);
-                        }
-                    }, "OptionsService.SetOptions");
-                }
+                        handler(this, e);
+                    }
+                }, "OptionsService.SetOptions");
             }
 
             private ImmutableArray<EventHandler<OptionChangedEventArgs>> GetEventHandlers()
@@ -98,7 +97,7 @@ private ImmutableArray<EventHandler<OptionChangedEventArgs>> GetEventHandlers()
 
                 remove
                 {
-                    lock(_gate)
+                    lock (_gate)
                     {
                         _eventHandlers = _eventHandlers.Remove(value);
                     }