NetworkVariable is written to, but doesn't know its NetworkBehaviour yet. Are you modifying a NetworkVariable before the NetworkObject is spawned?

[ezoray]

Description

I'm getting this warning when despawning a network object with Despawn(true) immediately after hiding the object from the client. It looks to relate to the fix that went in for #2143.

Reproduce Steps

Hide the object from client - object.NetworkObject.NetworkHide(clientId)
Despawn the object - object.NetworkObject.Despawn(true)

Actual Outcome

It looks like I get the above warning for each of the network variables in the object.

Expected Outcome

Object should despawn without warnings.

Environment

• OS: macOS Big Sur
• Unity Version: 2020 LTS
• Netcode Version: develop

Additional Context

There may be more at play than the above, I've not reproduced it in a test project.

[jeffreyrainy]

Thank you for the report! The quick iterations you are performing are really helpful.

I could repro in our test suite, with just:

m_NetSpawnedObject1.GetComponent<ShowHideObject>().MyNetworkVariable.Value++;
m_NetSpawnedObject1.Despawn();

It seems to occur if the object being despawned still has NetworkVariables that didn't get written yet. If the two lines above are done on different frames, then the issue(the warning log) doesn't show.

I'll fix it by cleaning up the pending NetworkVariable write, at Despawn time.

[ezoray]

@jeffreyrainy You're welcome. I just wanted to ask if it's possible to add an identifier like the netId to localise the error as the stack trace didn't give anything away so I had to do a bit digging to find the problem.

[jeffreyrainy]

add an identifier like the netId to localise the error as the stack trace didn't give anything away so I had to do a bit digging to find the problem

Sadly, no. I know how annoying this is (been there done that too). We're kind-of stuck with the NetworkVariableBase abstract base class that knows nothing of the context. The best I can suggest, while developing, in-editor, is to set a breakpoint on that warning, if you get it. When it hits, typically, in the callstack leading to it you'll have a NetworkObject writing to a NetworkVariable. The GameObject.Name property will help you figure which object it is.

But hopefully, after the next fix, you should simply not get that warning. :-)

[ezoray]

Ah okay, thanks for the tip. :)

[ashwinimurt]

Already has a PR with fix, no need to import to Jira