fix case 1244430 removing camera comp from prefab (#1953)

* fix case 1244430 removing camera comp from prefab

* Updated change log

Co-authored-by: sebastienlagarde <[email protected]>

Author: martint-unity

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

@@ -114,6 +114,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed a warning in materialevalulation
 - Fixed an error when building the player.
 - Fixed issue with box light not visible if range is below one and range attenuation is off.
+- Fixed an issue that caused a null reference when deleting camera component in a prefab. (case 1244430)
 
 ### Changed
 - Preparation pass for RTSSShadows to be supported by render graph.

com.unity.render-pipelines.high-definition/Editor/RenderPipeline/Camera/HDCameraEditor.cs

@@ -78,15 +78,32 @@ public void RemoveComponent(Camera camera, IEnumerable<Component> dependencies)
                 return;
             }
 
-            Undo.SetCurrentGroupName("Remove HD Camera");
-            var additionalCameraData = camera.GetComponent<HDAdditionalCameraData>();
-            if (additionalCameraData)
+            var isAssetEditing = EditorUtility.IsPersistent(camera);
+            try
             {
-                Undo.DestroyObjectImmediate(additionalCameraData);
+                if (isAssetEditing)
+                {
+                    AssetDatabase.StartAssetEditing();
+                }
+
+                Undo.SetCurrentGroupName("Remove HD Camera");
+                var additionalCameraData = camera.GetComponent<HDAdditionalCameraData>();
+                if (additionalCameraData != null)
+                {
+                    Undo.DestroyObjectImmediate(additionalCameraData);
+                }
+
+                Undo.DestroyObjectImmediate(camera);
+            }
+            finally
+            {
+                if (isAssetEditing)
+                {
+                    AssetDatabase.StopAssetEditing();
+                }
             }
-            Undo.DestroyObjectImmediate(camera);
         }
-        
+
         [MenuItem("CONTEXT/Camera/Reset", false, 0)]
         static void ResetCamera(MenuCommand menuCommand)
         {