SetParent() on nested NetworkObject appears to work, but logs errors, when using PredictedOwner

[curiousdustin]

General
Unity version: 6000.0.41f1
Fish-Networking version: 4.6.7hf0R, 4.67.8R
Discord link: NetworkObject.SetParent() after PredictedOwner.TakeOwnership() causes Already Contains X errors

Screen Recording: Video
Sample Project: SetParentErrors.unitypackage.zip

Description
When PredictedOwner is used to TakeOwnership of a NetworkObject that is nested within another NetworkObject, SetParent is used to change the nesting, and RemoveOwnership is used to return ownership to the server, Already contains errors are logged even though the behavior seems to continue as expected.

These errors do not occur if either:

• RemoveOwnership is never called.
• The NetworkObjects involved are both on the root level.

Replication
Steps to reproduce the behavior:

1. Create the following NetworkObjects, in this hierarchy:
   -- MainParent (NetworkObject)
   ---- Square (NetworkObject, PredictedOwner, NetworkTransform (Synchronize Parent ☑))
   ---- Circle (NetworkObject, PredictedOwner, NetworkTransform (Synchronize Parent ☑))

2. Using default NetworkManager, load the scene as Host (Start Server, Start Client)

3. At runtime, execute the following code bits in order:

[ServerRpc(RequireOwnership = false)]
public void RpcReturnOwnershipToServer()
{
    RemoveOwnership();
}

// In my case, to start dragging an object
Circle.predictedOwner.TakeOwnership(true);

// In my case, when object is dropped on top of Sqaure
Circle.NetworkObject.SetParent(Square.NetworkObject);

// In my case, called immediately after SetParent
Circle.RpcReturnOwnershipToServer(); (Calls RemoveOwnership on Server)

4. Observe that Circle is indeed now nested within Sqaure.

5. However, Observe error:
   Already contains Circle

6. Observe similar error every time SetParent is called on either Square or Circle from here on.

Expected behavior
On the surface, the actual behavior appears to be fine. But I would expect no error to be logged.

Screenshots

[FirstGearGames]

Planned investigation shortly after the release of 4.6.9

[FirstGearGames]

Issue_906.zip

Thank you. I was able to reproduce in your test project.

I modified the test project slightly (and attached) to remove the offline scene as it did not seem to be needed.

Steps to reproduce:

• Open scene 906 in an Editor.
• Hit play (will run as Host).
• In the game window press and drag the top circle onto the square (observe error).

Issue does not happen when dragging lower circle.

There was something else that caught my attention though -- when I open a second editor as client-only, and this editor drags the top circle, there are no errors but the object is not nested either. Is the object expected to be nested if set by client-only?

[curiousdustin]

My intention for this is that YES, the parenting/nesting would be synchronized to other clients.

However, I am not sure if I am implementing this correctly in order for that to happen.

Network Transform has the Synchronize Parent option enabled.

The general flow is:

• mouse down: take ownership via predicted owner
• mouse move: update transform position
• mouse up: update parent/nesting, server RPC to return ownership

So, yes the parent is set by the client-only, but it has ownership, and network transform synchronize parent enabled. In this case I am expecting the nesting to sync, but maybe I'm not understanding something.

[FirstGearGames]

If using TakeOwnership and NT is client authoritative then yes, client-only should be able to update the parent. Sounds like this is also an issue to be addressed. I will need to address this after the 4.6.10 release but will have the error one resolved in 4.6.10.

…

On Fri, Jul 11, 2025, 12:26 PM Dustin Bahr ***@***.***> wrote: *curiousdustin* left a comment (FirstGearGames/FishNet#906) <#906 (comment)> My intention for this is that YES, the parenting/nesting would be synchronized to other clients. However, I am not sure if I am implementing this correctly in order for that to happen. Network Transform has the Synchronize Parent option enabled. The general flow is: - mouse down: take ownership via predicted owner - mouse move: update transform position - mouse up: update parent/nesting, server RPC to return ownership So, yes the parent is set by the client-only, but it has ownership, and network transform synchronize parent enabled. In this case I am expecting the nesting to sync, but maybe I'm not understanding something. — Reply to this email directly, view it on GitHub <#906 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGPJC3XMO7ANLPDHOKFMN633H7QUPAVCNFSM6AAAAAB5EGUDJKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTANRSHEZTCNRUGU> . You are receiving this because you commented.Message ID: ***@***.***>

[FirstGearGames]

Your issue is resolved in 4.6.10.

There is the other matter of SetParent failing silently on client-only. I've created a new issue here #940