fix: client not tracking changes to layer weights [MTT-7166] (#2674)

* fix

This resolves the issue with clients not keep track of changes to the layer weights.

* test

Validates the fix to assure clients receive weight updates and track them in order to be able to apply changes when needed.

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -7,10 +7,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 Additional documentation and release notes are available at [Multiplayer Documentation](https://docs-multiplayer.unity3d.com).
 
 ## [Unreleased]
+### Added
 
 ### Fixed
 
-- Fixed "writing past the end of the buffer" error when calling ResetDirty() on managed network variables that are larger than 256 bytes when serialized.
+- Fixed issue where `NetworkAnimator` was not internally tracking changes to layer weights which prevented proper layer weight synchronization back to the original layer weight value. (#2674)
+- Fixed "writing past the end of the buffer" error when calling ResetDirty() on managed network variables that are larger than 256 bytes when serialized. (#2670)
+
+### Changed
 
 ## [1.5.2] - 2023-07-24
 

com.unity.netcode.gameobjects/Components/NetworkAnimator.cs

@@ -1137,6 +1137,7 @@ internal void UpdateAnimationState(AnimationState animationState)
                 if (m_LayerWeights[animationState.Layer] != animationState.Weight)
                 {
                     m_Animator.SetLayerWeight(animationState.Layer, animationState.Weight);
+                    m_LayerWeights[animationState.Layer] = animationState.Weight;
                 }
             }
 

testproject/Assets/Tests/Runtime/Animation/NetworkAnimatorTests.cs

@@ -495,17 +495,32 @@ public void WeightUpdateTests([Values] OwnerShipMode ownerShipMode, [Values] Aut
                 animatorTestHelper = AnimatorTestHelper.ServerSideInstance;
             }
 
+            var originalWeight = animatorTestHelper.GetLayerWeight(1);
+
             animatorTestHelper.SetLayerWeight(1, 0.75f);
             // Wait for all instances to update their weight value for layer 1
             success = WaitForConditionOrTimeOutWithTimeTravel(() => AllInstancesSameLayerWeight(ownerShipMode, 1, 0.75f));
             Assert.True(success, $"Timed out waiting for all instances to match weight 0.75 on layer 1!");
 
+            animatorTestHelper.SetLayerWeight(1, originalWeight);
+            // Wait for all instances to update their weight value for layer 1
+            success = WaitForConditionOrTimeOutWithTimeTravel(() => AllInstancesSameLayerWeight(ownerShipMode, 1, originalWeight));
+            Assert.True(success, $"Timed out waiting for all instances to match weight {originalWeight} on layer 1!");
+
+            // Now set the layer weight to 0
+            animatorTestHelper.SetLayerWeight(1, 0.0f);
+
             // Now late join a client
             CreateAndStartNewClientWithTimeTravel();
 
             // Verify the late joined client is synchronized to the changed weight
-            success = WaitForConditionOrTimeOutWithTimeTravel(() => AllInstancesSameLayerWeight(ownerShipMode, 1, 0.75f));
-            Assert.True(success, $"[Late-Join] Timed out waiting for all instances to match weight 0.75 on layer 1!");
+            success = WaitForConditionOrTimeOutWithTimeTravel(() => AllInstancesSameLayerWeight(ownerShipMode, 1, 0.0f));
+            Assert.True(success, $"[Late-Join] Timed out waiting for all instances to match weight 0 on layer 1!");
+
+            animatorTestHelper.SetLayerWeight(1, originalWeight);
+            // Wait for all instances to update their weight value for layer 1
+            success = WaitForConditionOrTimeOutWithTimeTravel(() => AllInstancesSameLayerWeight(ownerShipMode, 1, originalWeight));
+            Assert.True(success, $"Timed out waiting for all instances to match weight {originalWeight} on layer 1!");
 
             AnimatorTestHelper.IsTriggerTest = false;
             VerboseDebug($" ------------------ Weight Test [{ownerShipMode}] Stopping ------------------ ");