From 7c3cc69d3f7890423f7c07a40bd1881ce36d2bda Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@users.noreply.github.com>
Date: Mon, 3 Jan 2022 19:06:39 +0100
Subject: [PATCH] Check for null visual parent. (#7298)

It shouldn't be possible to come across a null visual parent here because the visual should be attached to the visual tree, but according to #6930, it is. Because we don't have a repro here, defensively return a null value instead of throwing if we hit this case.
---
 src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
index c6cdf474bb..4989785b80 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
@@ -126,7 +126,12 @@ namespace Avalonia.Rendering.SceneGraph
 
             while (node == null && visual.IsVisible)
             {
-                visual = visual.VisualParent;
+                var parent = visual.VisualParent;
+
+                if (parent is null)
+                    return null;
+
+                visual = parent;
                 node = scene.FindNode(visual);
             }