From ee28f970aed1487e5dac94957de12063c42e20b4 Mon Sep 17 00:00:00 2001
From: Kitty Draper <kitty.draper@unity3d.com>
Date: Thu, 13 Jul 2023 11:52:57 -0500
Subject: [PATCH 1/3] fix: Add null check in TrySetParent

fixes #2621
---
 com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs b/com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs
index 3643d44a57..cd98c11e20 100644
--- a/com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs
+++ b/com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs
@@ -733,6 +733,12 @@ internal void SetNetworkParenting(ulong? latestParent, bool worldPositionStays)
         /// <returns>Whether or not reparenting was successful.</returns>
         public bool TrySetParent(Transform parent, bool worldPositionStays = true)
         {
+            // If we are removing ourself from a parent
+            if (parent == null)
+            {
+                return TrySetParent((NetworkObject)null, worldPositionStays);
+            }
+
             var networkObject = parent.GetComponent<NetworkObject>();
 
             // If the parent doesn't have a NetworkObjet then return false, otherwise continue trying to parent

From 76aa9bb2dbf2d48162c865ce10baa5d43b59f407 Mon Sep 17 00:00:00 2001
From: Kitty Draper <kitty.draper@unity3d.com>
Date: Thu, 13 Jul 2023 12:25:51 -0500
Subject: [PATCH 2/3] Added tests

---
 .../NetworkObjectParentingTests.cs            | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/testproject/Assets/Tests/Runtime/ObjectParenting/NetworkObjectParentingTests.cs b/testproject/Assets/Tests/Runtime/ObjectParenting/NetworkObjectParentingTests.cs
index 65fb476822..1b1257a6c3 100644
--- a/testproject/Assets/Tests/Runtime/ObjectParenting/NetworkObjectParentingTests.cs
+++ b/testproject/Assets/Tests/Runtime/ObjectParenting/NetworkObjectParentingTests.cs
@@ -309,6 +309,49 @@ public IEnumerator SetParentTryAPI()
                 Assert.That(m_Cube_NetObjs[setIndex + 1].parent, Is.EqualTo(m_Dude_LeftArm_NetObjs[setIndex + 1]));
                 Assert.That(m_Cube_NetBhvs[setIndex + 1].ParentNetworkObject, Is.EqualTo(m_Dude_LeftArm_NetObjs[setIndex + 1].GetComponent<NetworkObject>()));
             }
+
+            Transform nullTransform = null;
+            GameObject nullGameObject = null;
+            NetworkObject nullNetworkObject = null;
+
+
+            Assert.That(m_Cube_NetObjs[0].GetComponent<NetworkObject>().TrySetParent(nullTransform));
+            Assert.That(m_Cube_NetBhvs[0].ParentNetworkObject, Is.EqualTo(null));
+
+            nextFrameNumber = Time.frameCount + 2;
+            yield return new WaitUntil(() => Time.frameCount >= nextFrameNumber);
+
+            for (int setIndex = 0; setIndex < k_ClientInstanceCount; setIndex++)
+            {
+                Assert.That(m_Cube_NetObjs[setIndex + 1].parent, Is.EqualTo(null));
+                Assert.That(m_Cube_NetBhvs[setIndex + 1].ParentNetworkObject, Is.EqualTo(null));
+            }
+
+
+            Assert.That(m_Cube_NetObjs[0].GetComponent<NetworkObject>().TrySetParent(nullGameObject));
+            Assert.That(m_Cube_NetBhvs[0].ParentNetworkObject, Is.EqualTo(null));
+
+            nextFrameNumber = Time.frameCount + 2;
+            yield return new WaitUntil(() => Time.frameCount >= nextFrameNumber);
+
+            for (int setIndex = 0; setIndex < k_ClientInstanceCount; setIndex++)
+            {
+                Assert.That(m_Cube_NetObjs[setIndex + 1].parent, Is.EqualTo(null));
+                Assert.That(m_Cube_NetBhvs[setIndex + 1].ParentNetworkObject, Is.EqualTo(null));
+            }
+
+
+            Assert.That(m_Cube_NetObjs[0].GetComponent<NetworkObject>().TrySetParent(nullNetworkObject));
+            Assert.That(m_Cube_NetBhvs[0].ParentNetworkObject, Is.EqualTo(null));
+
+            nextFrameNumber = Time.frameCount + 2;
+            yield return new WaitUntil(() => Time.frameCount >= nextFrameNumber);
+
+            for (int setIndex = 0; setIndex < k_ClientInstanceCount; setIndex++)
+            {
+                Assert.That(m_Cube_NetObjs[setIndex + 1].parent, Is.EqualTo(null));
+                Assert.That(m_Cube_NetBhvs[setIndex + 1].ParentNetworkObject, Is.EqualTo(null));
+            }
         }
     }
 }

From 63f0369559f6d1ce4cbb2692b7b8682585f3eb71 Mon Sep 17 00:00:00 2001
From: Kitty Draper <kitty.draper@unity3d.com>
Date: Thu, 13 Jul 2023 12:27:22 -0500
Subject: [PATCH 3/3] Changelog

---
 com.unity.netcode.gameobjects/CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/com.unity.netcode.gameobjects/CHANGELOG.md b/com.unity.netcode.gameobjects/CHANGELOG.md
index 1a0dfaa2d6..72e40193c0 100644
--- a/com.unity.netcode.gameobjects/CHANGELOG.md
+++ b/com.unity.netcode.gameobjects/CHANGELOG.md
@@ -15,6 +15,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 
 - Fixed issue where `NetworkObject.SpawnWithObservers` was not being honored for late joining clients. (#2623)
 - Fixed issue where invoking `NetworkManager.Shutdown` multiple times, depending upon the timing, could cause an exception. (#2622)
+- Fixed a crash when calling TrySetParent with a null Transform (#2625)
 
 ## Changed