Fix issue with disc area light editor not updating #1526

Author: FrancescoC-unity

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed error about layers when disabling emissive mesh for area lights.
 - Fixed issue with sun icon being clipped in the look dev window. 
 - Fixed lookdev toggling renderers that are set to non editable or are hidden in the inspector.
+- Fixed issue causing the editor field not updating the disc area light radius.
 
 ### Changed
 - Remove MSAA debug mode when renderpipeline asset has no MSAA

com.unity.render-pipelines.high-definition/Runtime/Lighting/Light/HDAdditionalLightData.cs

@@ -2684,7 +2684,9 @@ void UpdateShapeSize()
             shapeHeight = m_ShapeHeight;
 
 #if UNITY_EDITOR
-            legacyLight.areaSize = new Vector2(shapeWidth, shapeHeight);
+            // We don't want to update the disc area since their shape is largely handled by builtin.
+            if (GetLightTypeAndShape() != HDLightTypeAndShape.DiscArea)
+                legacyLight.areaSize = new Vector2(shapeWidth, shapeHeight);
 #endif
         }