From acdc366fd0c14b05b5d80e96216f65e05791d904 Mon Sep 17 00:00:00 2001
From: Pavlos Mavridis <pavlos.mavridis@unity3d.com>
Date: Mon, 12 Oct 2020 23:02:22 +0200
Subject: [PATCH 1/2] Fix null reference on undo callback

---
 .../Editor/Compositor/CompositorWindow.cs                       | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/com.unity.render-pipelines.high-definition/Editor/Compositor/CompositorWindow.cs b/com.unity.render-pipelines.high-definition/Editor/Compositor/CompositorWindow.cs
index 95215eeaad0..eee3264a789 100644
--- a/com.unity.render-pipelines.high-definition/Editor/Compositor/CompositorWindow.cs
+++ b/com.unity.render-pipelines.high-definition/Editor/Compositor/CompositorWindow.cs
@@ -206,6 +206,8 @@ void UndoCallback()
             s_SelectionIndex = m_Editor.selectionIndex;
 
             CompositionManager compositor = CompositionManager.GetInstance();
+            // The compositor might be null even if the CompositionManagerEditor is not (in case the user switches from a scene with a compositor to a scene without one)
+            if (compositor)
             {
                 // Some properties were changed, mark the profile as dirty so it can be saved if the user saves the scene
                 EditorUtility.SetDirty(compositor);

From 15a764e69d65f751f9c104588dfd690b07d985f1 Mon Sep 17 00:00:00 2001
From: Pavlos Mavridis <pavlos.mavridis@unity3d.com>
Date: Wed, 14 Oct 2020 09:54:54 +0200
Subject: [PATCH 2/2] Update changelog

---
 com.unity.render-pipelines.high-definition/CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/com.unity.render-pipelines.high-definition/CHANGELOG.md b/com.unity.render-pipelines.high-definition/CHANGELOG.md
index 4f44be46ea2..8c07cc3c1bd 100644
--- a/com.unity.render-pipelines.high-definition/CHANGELOG.md
+++ b/com.unity.render-pipelines.high-definition/CHANGELOG.md
@@ -161,6 +161,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed issue where multiple cameras would cause GC each frame.
 - Fixed after post process rendering pass options not showing for unlit ShaderGraphs.
 - Fixed a migration issue with the rendering queue in ShaderGraph when upgrading to 10.x;
+- Fixed null reference in the Undo callback of the graphics compositor 
 
 ### Changed
 - Preparation pass for RTSSShadows to be supported by render graph.