FIX: Custom processors serialises enum by index rather than by value.

Assets/Tests/InputSystem.Editor/CustomProcessorEnumTest.cs

@@ -0,0 +1,113 @@
+#if UNITY_EDITOR && UNITY_INPUT_SYSTEM_PROJECT_WIDE_ACTIONS && UNITY_6000_0_OR_NEWER
+
+using System;
+using NUnit.Framework;
+using System.Collections;
+using System.Linq;
+using UnityEditor;
+using UnityEngine;
+using UnityEngine.InputSystem;
+using UnityEngine.InputSystem.Editor;
+using UnityEngine.TestTools;
+using UnityEngine.UIElements;
+
+public enum SomeEnum
+{
+    OptionA = 10,
+    OptionB = 20,
+    OptionC = 50,
+    OptionD = 100
+}
+
+#if UNITY_EDITOR
+[InitializeOnLoad]
+#endif
+public class CustomProcessor : InputProcessor<float>
+{
+    public SomeEnum SomeEnum;
+
+#if UNITY_EDITOR
+    static CustomProcessor()
+    {
+        Initialize();
+    }
+#endif
+
+    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
+    private static void Initialize()
+    {
+        InputSystem.RegisterProcessor<CustomProcessor>();
+    }
+
+    public override float Process(float value, InputControl control)
+    {
+        return value;
+    }
+}
+
+internal class CustomProcessorEnumTest : UIToolkitBaseTestWindow<InputActionsEditorWindow>
+{
+    InputActionAsset m_Asset;
+
+    public override void OneTimeSetUp()
+    {
+        base.OneTimeSetUp();
+        m_Asset = AssetDatabaseUtils.CreateAsset<InputActionAsset>();
+
+        var actionMap = m_Asset.AddActionMap("Action Map");
+
+         actionMap.AddAction("Action", InputActionType.Value, processors: "Custom(SomeEnum=10)");
+    }
+
+    public override void OneTimeTearDown()
+    {
+        AssetDatabaseUtils.Restore();
+        base.OneTimeTearDown();
+    }
+
+    public override IEnumerator UnitySetup()
+    {
+        m_Window = InputActionsEditorWindow.OpenEditor(m_Asset);
+        yield return base.UnitySetup();
+    }
+
+    [UnityTest]
+    public IEnumerator CustomProcessorEnum_SerialiseTheValue_InAsset()
+    {
+        var json = m_Window.currentAssetInEditor.ToJson();
+
+        Assert.That(json.Contains("Custom(SomeEnum=10)"), Is.True,
+            "Serialized JSON does not contain the expected custom processor string for OptionA.");
+
+        var dropdownList = m_Window.rootVisualElement.Query<DropdownField>().Where(d => d.choices != null && d.choices.Contains("OptionA") && d.choices.Contains("OptionB")).ToList();
+        Assume.That(dropdownList.Count > 0, Is.True, "Enum parameter dropdown not found in the UI.");
+
+        var dropdown = dropdownList.First();
+
+        var newIndex = dropdown.choices.IndexOf("OptionB"); 
+        var oldValue = dropdown.value;
+        var newValue = dropdown.choices[newIndex];
+
+        dropdown.Focus();
+        dropdown.value = newValue;
+
+        var changeEvent = ChangeEvent<Enum>.GetPooled(SomeEnum.OptionA, SomeEnum.OptionC);
+        changeEvent.target = dropdown;
+        dropdown.SendEvent(changeEvent);
+
+        var saveButton = m_Window.rootVisualElement.Q<Button>("save-asset-toolbar-button");
+        Assume.That(saveButton, Is.Not.Null, "Save Asset button not found in the UI.");
+        saveButton.Focus();
+        SimulateClickOn(saveButton);
+
+        Assert.That(dropdown.value, Is.EqualTo(newValue));
+
+        var updatedJson = m_Window.currentAssetInEditor.ToJson();
+
+        Assert.That(updatedJson.Contains("Custom(SomeEnum=20)"), Is.True, "Serialized JSON does not contain the updated custom processor string for OptionB.");
+
+        yield return null;
+    }
+}
+#endif
+

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -22,6 +22,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed Inspector Window being refreshed all the time when a PlayerInput component is present with Invoke Unity Events nofication mode chosen [ISXB-1448](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1448)
 - Fixed an issue where an action with a name containing a slash "/" could not be found via `InputActionAsset.FindAction(string,bool)`. [ISXB-1306](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1306).
 - Fixed Gamepad stick up/down inputs that were not recognized in WebGL. [ISXB-1090](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1090)
+- Fixed Action with custom processor serialises enums by index rather than by value. [ISXB-1474](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1474)
 
 ## [1.14.0] - 2025-03-20
 

Packages/com.unity.inputsystem/InputSystem/Editor/AssetEditor/ParameterListView.cs

@@ -278,10 +278,11 @@ void OnEditEnd()
 
                 if (parameter.isEnum)
                 {
-                    var intValue = parameter.value.value.ToInt32();
-                    var field = new DropdownField(label.text, parameter.enumNames.Select(x => x.text).ToList(), intValue);
+                    var currentEnumValue = parameter.value.value.ToInt32();   
+                    var selectedIndex = parameter.enumValues.IndexOf(currentEnumValue);
+                    var field = new DropdownField(label.text, parameter.enumNames.Select(x => x.text).ToList(), selectedIndex);
                     field.tooltip = label.tooltip;
-                    field.RegisterValueChangedCallback(evt => OnValueChanged(ref parameter, field.index, closedIndex));
+                    field.RegisterValueChangedCallback(evt => OnValueChanged(ref parameter, parameter.enumValues[field.index], closedIndex));
                     field.RegisterCallback<BlurEvent>(_ => OnEditEnd());
                     root.Add(field);
                 }