Added ability to only remove composite part bindings and not binding itself

Assets/Tests/InputSystem/CoreTests_Actions.cs

@@ -3644,6 +3644,32 @@ public void Actions_CanAddBindingsToActions_ToExistingComposite()
                 .Property("path").EqualTo("<Keyboard>/rightArrow"));
     }
 
+    [Test]
+    [Category("Actions")]
+    public void Actions_CanRemovePartBindings_ButNotExistingComposite()
+    {
+        var keyboard = InputSystem.AddDevice<Keyboard>();
+
+        var action = new InputAction();
+        action.AddCompositeBinding("Axis")
+            .With("Negative", "<Keyboard>/a")
+            .With("Positive", "<Keyboard>/d");
+        action.ChangeCompositeBinding("Axis").Erase(onlyRemoveCompositeParts: true);
+
+        Assert.That(action.bindings, Has.Count.EqualTo(1));
+        Assert.That(action.controls, Has.Count.EqualTo(0));
+
+        try
+        {
+            action.AddBinding("<Keyboard>/a");
+            action.ChangeBinding(1).Erase(onlyRemoveCompositeParts: true);
+        }
+        catch (InvalidOperationException ex)
+        {
+            Assert.That(ex.Message, Is.EqualTo("Binding should be a composite binding"));
+        }
+    }
+
     [Serializable]
     public enum Modification
     {

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -14,6 +14,10 @@ however, it has to be formatted properly to pass verification tests.
 
 - Fixed unclosed profiler marker in `InvokeCallbacksSafe_AnyCallbackReturnsTrue` which would lead to eventually broken profiler traces in some cases like using `PlayerInput` (case ISXB-393).
 
+### Added
+
+- Added `Erase(onlyRemoveCompositeParts: true)` to be able to remove only binding parts of the composite binding but not the composite binding itself. Based on the user contribution from [steinbitglis](https://github.com/steinbitglis) in [#1360](https://github.com/Unity-Technologies/InputSystem/pull/1360).
+
 ## [1.5.0] - 2023-01-24
 
 ### Added

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

@@ -1564,19 +1564,26 @@ private BindingSyntax IteratePartBinding(bool next, string partName)
             /// that got erased was the last one in the array).
             /// </remarks>
             /// <exception cref="InvalidOperationException">The instance is not <see cref="valid"/>.</exception>
-            public void Erase()
+            public void Erase(bool onlyRemoveCompositeParts = false)
             {
                 if (!valid)
                     throw new InvalidOperationException("Instance not valid");
 
                 var isComposite = m_ActionMap.m_Bindings[m_BindingIndexInMap].isComposite;
-                ArrayHelpers.EraseAt(ref m_ActionMap.m_Bindings, m_BindingIndexInMap);
+                if (onlyRemoveCompositeParts && !isComposite)
+                    throw new InvalidOperationException("Binding should be a composite binding");
+
+                var index = m_BindingIndexInMap;
+                if (!onlyRemoveCompositeParts)
+                    ArrayHelpers.EraseAt(ref m_ActionMap.m_Bindings, index);
+                else
+                    index++;
 
                 // If it's a composite, also erase part bindings.
                 if (isComposite)
                 {
-                    while (m_BindingIndexInMap < m_ActionMap.m_Bindings.LengthSafe() && m_ActionMap.m_Bindings[m_BindingIndexInMap].isPartOfComposite)
-                        ArrayHelpers.EraseAt(ref m_ActionMap.m_Bindings, m_BindingIndexInMap);
+                    while (index < m_ActionMap.m_Bindings.LengthSafe() && m_ActionMap.m_Bindings[index].isPartOfComposite)
+                        ArrayHelpers.EraseAt(ref m_ActionMap.m_Bindings, index);
                 }
 
                 m_ActionMap.OnBindingModified();