FIX: ISXB-895 Fixed an issue where InputActionAsset.FindAction would unexpectedly throw System.NullReferenceException. (#1937)

* FIX: Fixed an issue where InputActionAsset.FindAction would throw even if throwIfNotFound is false.

Author: ekcoh

Assets/Tests/InputSystem/CoreTests_Actions.cs

@@ -7861,6 +7861,19 @@ public void Actions_CanLookUpMapInAssetById_UsingOldBracedFormat()
         Assert.That(asset.FindActionMap($"{{{Guid.NewGuid().ToString()}}}"), Is.Null);
     }
 
+    [Test]
+    [Category("Actions")]
+    [Description("ISXB-895 Can attempt to lookup non-existent action in asset by path")]
+    public void Actions_CanAttemptToLookUpNonExistentActionInAssetByPath()
+    {
+        var asset = ScriptableObject.CreateInstance<InputActionAsset>();
+
+        Assert.That(asset.FindAction("Map/Action1"), Is.Null);
+
+        var map = asset.AddActionMap("Map");
+        Assert.That(asset.FindAction("Map/Action1"), Is.Null); // ISXB-895 using a path to find non-existent (NullReferenceException)
+    }
+
     [Test]
     [Category("Actions")]
     public void Actions_CanLookUpActionInAssetByName()

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -18,6 +18,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed prefabs and missing default control scheme used by PlayerInput component are now correctly shown in the inspector [ISXB-818](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-818).
 - Fixed error thrown when Cancelling Control Scheme creation in Input Actions Editor.
 - Fixed Scheme Name in Control Scheme editor menu that gets reset when editing devices [ISXB-763](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-763).
+- Fixed an issue where `InputActionAsset.FindAction(string, bool)` would throw `System.NullReferenceException` instead of returning `null` if searching for a non-existent action with an explicit action path and using `throwIfNotFound: false`, e.g. searching for "Map/Action" when `InputActionMap` "Map" exists but no `InputAction` named "Action" exists within that map [ISXB-895](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-895).
 
 ## [1.8.2] - 2024-04-29
 

Packages/com.unity.inputsystem/InputSystem/Actions/InputActionAsset.cs

@@ -570,14 +570,16 @@ public InputAction FindAction(string actionNameOrId, bool throwIfNotFound = fals
                             continue;
 
                         var actions = map.m_Actions;
-                        for (var n = 0; n < actions.Length; ++n)
+                        if (actions != null)
                         {
-                            var action = actions[n];
-                            if (Substring.Compare(action.name, actionName,
-                                StringComparison.InvariantCultureIgnoreCase) == 0)
-                                return action;
+                            for (var n = 0; n < actions.Length; ++n)
+                            {
+                                var action = actions[n];
+                                if (Substring.Compare(action.name, actionName,
+                                    StringComparison.InvariantCultureIgnoreCase) == 0)
+                                    return action;
+                            }
                         }
-
                         break;
                     }
                 }