FIX: Input Actions editor window throws a "Failed to load asset" exception on startup when its layout is restored in a different project [UUM-144318]

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 
 - Fixed an `OverflowException` when creating a control scheme (or other named item) whose all-numeric name exceeds `Int32.MaxValue`, which previously discarded the entered name and fell back to the default [UUM-145766](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-145766)
+- Fixed the Input Actions editor window logging a "Failed to load asset" exception on editor startup when its saved window layout was restored in a project where the referenced asset GUID did not resolve; the window now closes quietly instead [UUM-144318](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-144318)
 - Empty foldouts are no longer shown for processors and interactions that have no settings (e.g. "Invert") [UUM-144325](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-144325)
 - Fixed the Input Actions editor toolbar buttons being clipped when the Action Properties panel grew tall enough to show a scrollbar
 - Fixed the Control Schemes dropdown in the Input Actions editor continuing to display a deleted scheme's name after the last control scheme was removed, instead of resetting to "No Control Schemes" until the asset was saved or the editor reopened. [UUM-141563](https://issuetracker.unity3d.com/product/unity/issues/guid/UUM-141563)

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs

@@ -208,7 +208,12 @@ private void CreateGUI() // Only domain reload
                     var asset = AssetDatabase.LoadAssetAtPath<InputActionAsset>(assetPath);
 
                     if (asset == null)
-                        throw new Exception($"Failed to load asset \"{assetPath}\". The file may have been deleted or moved.");
+                    {
+                        // Can happen when an asset is deleted while the window is open.
+                        // Delay the closure to avoid null-refs on repaint.
+                        EditorApplication.delayCall += Close;
+                        return;
+                    }
 
                     m_AssetJson = InputActionsEditorWindowUtils.ToJsonWithoutName(asset);