NullReferenceException when right clicking in the Hierarchy window

[Edvinas01]

Versions

• Unity: 2020.3.20f1.
• Smart Hierarchy: 0.3.1.

Repro steps

• Create new scene.
• Open the scene.
• Right click in the Hierarchy window.
• Context menu doesn't open and an exception is thrown.

Exception

NullReferenceException: Object reference not set to an instance of an object
AV.Hierarchy.GenericMenuUtil.GetItems (UnityEditor.GenericMenu menu) (at Library/PackageCache/com.av.smart-hierarchy@0.3.1/Reflected/GenericMenuUtil.cs:21)
AV.Hierarchy.CopyPasteCommands.<OnInitialize>g__ReplaceMenuFunctions|6_2 (UnityEditor.GenericMenu menu) (at Library/PackageCache/com.av.smart-hierarchy@0.3.1/Base/Commands/CopyPasteCommands.cs:28)
AV.Hierarchy.CopyPasteCommands+<>c.<OnInitialize>b__6_0 (UnityEditor.GenericMenu menu, UnityEngine.GameObject o) (at Library/PackageCache/com.av.smart-hierarchy@0.3.1/Base/Commands/CopyPasteCommands.cs:21)
UnityEditor.SceneManagement.SceneHierarchyHooks.AddCustomGameObjectContextMenuItems (UnityEditor.GenericMenu menu, UnityEngine.GameObject gameObject) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchy.CreateGameObjectContextClick (UnityEditor.GenericMenu menu, System.Int32 contextClickedItemID) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchy.ContextClickOutsideItems () (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.IMGUI.Controls.TreeViewController.HandleUnusedEvents () (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (UnityEngine.Rect rect, System.Int32 keyboardControlID) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchy.DoTreeView (System.Single searchPathHeight) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchy.OnGUI (UnityEngine.Rect rect) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchyWindow.DoSceneHierarchy () (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.SceneHierarchyWindow.OnGUI () (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition, UnityEngine.Rect viewRect) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.DockArea.DrawView (UnityEngine.Rect viewRect, UnityEngine.Rect dockAreaRect) (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEditor.DockArea.OldOnGUI () (at <83a38f5397d94e36a22efa3369c82390>:0)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, UnityEngine.Matrix4x4 worldTransform, UnityEngine.Rect clippingRect, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Boolean canAffectFocus) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUIRaw (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUI (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.IMGUIContainer.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.MouseEventDispatchingStrategy.SendEventToRegularTarget (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.MouseEventDispatchingStrategy.SendEventToTarget (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.MouseEventDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel iPanel) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.EventDispatcher.ApplyDispatchingStrategies (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, System.Boolean imguiEventIsInitiallyUsed) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& eventHandled) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.UIEventRegistration.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.UIElements.UIEventRegistration+<>c.<.cctor>b__1_2 (System.Int32 i, System.IntPtr ptr) (at <4c8a9874288b4fb78fa7fdbcd8065b00>:0)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& result) (at <00a477ed1abf4030be646c3244bd3667>:0)

[alexanderameye]

Something like this should work

  #if UNITY_2021_2_OR_NEWER
        static PropertyInfo menuItemsField = typeof(GenericMenu).GetProperty("menuItems",
            BindingFlags.NonPublic |
            BindingFlags.Instance);
        #else
        static FieldInfo menuItemsField = typeof(GenericMenu).GetField("menuItems",
            BindingFlags.NonPublic |
            BindingFlags.Instance);
        #endif

in the GenericMenuUtil.cs script. I hope a fix for this can be added.