From 4f660317140fc6b939be8aee27bc324a470b68be Mon Sep 17 00:00:00 2001
From: Falk David <falk@blender.org>
Date: Thu, 10 Aug 2023 16:05:17 +0200
Subject: [PATCH] GPv3: Fix TreeNode::parent_group() for root group

For the root group, the parent is `nullptr` so calling `parent_group()`
would fail. This fixes the issue by adding a null check and returning
`nullptr` otherwise.
---
 source/blender/blenkernel/intern/grease_pencil.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/source/blender/blenkernel/intern/grease_pencil.cc b/source/blender/blenkernel/intern/grease_pencil.cc
index cb43d0f83ac..1ef2e95d950 100644
--- a/source/blender/blenkernel/intern/grease_pencil.cc
+++ b/source/blender/blenkernel/intern/grease_pencil.cc
@@ -481,7 +481,10 @@ Layer &TreeNode::as_layer_for_write()
 
 LayerGroup *TreeNode::parent_group() const
 {
-  return &this->parent->wrap();
+  if (this->parent) {
+    return &this->parent->wrap();
+  }
+  return nullptr;
 }
 
 LayerMask::LayerMask()