Inconsistencies for `IsHost`, `IsClient`, `IsServer` between `NetworkBehavior` and `NetworkManager`

Description

The properties IsHost, IsClient, and IsServer of NetworkBehavior do not return the same value as the matching properties in NetworkManager if the associated NetworkObject has not yet been spawned.

Reproduce Steps

In a NetworkBehavior define the method:

// MyNetworkBehvaior.cs
public void AssertIsClient() {
    Debug.Assert(IsClient == NetworkManager.IsClient, "IsClient != NetworkManager.IsClient");
}

In the Start method of another component call

var instance = Instantiate(myNetworkBehaviorPrefab);
instance.GetComponent<MyNetworkBehavior>().AssertIsClient();

Actual Outcome

The assertion fails since the properties do not match.

Expected Outcome

The assertion passes because the properties are consistent between NetworkBehavior and NetworkManager.

Environment

• OS: Windows 10
• Unity Version: 2020.3
• Netcode Version: 1.2.0

Additional Context

It looks like the properties are assigned manually in UpdateNetworkProperties() during initialization. Is there are reason why the properties don’t just directly return the corresponding value from NetworkManager?

[RoxDevvv]

@NoelStephensUnity Very helpful thank you very much

[NoelStephensUnity]

@RoxDevvv I totally understand that it can be confusing initially, but maybe I can further explain to help better clarify why it is this way: When checking any netcode property within a NetworkBehaviour, you just need to think about the context of the check. Originally, those properties would default to using NetworkManager.Singleton which led to a different set of confusion if someone was checking just “IsHost” and making the assumption that you can then proceed to invoke RPCs or change NetworkVariables since the NetworkManager “is started”…but the context is within a NetworkBehaviour component that is tied/associated with a NetworkObject and the NetworkManager could be still connecting, still synchronizing with NetworkObjects, and various other states that IsServer, IsHost, or IsClient will not be enough information to assure your netcode script will be ok to execute. You can think of a NetworkObject, when it is not spawned but its associated GameObject is instantiated, as a not fully defined (“blank/generic”) object since it has no real network session state…which means it doesn’t know about the NetworkManager, who owns it, whether it is parented or not, and such. When a NetworkObject is spawned, it has been fully initialized and knows about such things.

Going back to just using something like an “!IsServer” (i.e. client only) check within a NetworkBehaviour could lead to other issues if the NetworkObject was not spawned and that value actually was set to a value…so in reality if IsClient, IsHost, and IsServer are all false then that translates to !IsSpawned (i.e. the NetworkManager has no defined role)… of course just those values by themselves could be a lot more confusing to use than just checking IsSpawned.

In the end, we were faced with either using a singleton reference within a “getter” accessor method for NetworkBehaviour properties (i.e. IsServer, IsHost, IsClient, and even NetworkManager itself) which could be expensive (processing wise) since those properties could potentially be used in many places within a NetworkBehavior component and there could be many instances of the same NetworkBehaviour component (assigned to unique NetworkObject instances)…we made the call to just not have NetworkBehaviour netcode related properties, especially those that were pulled from the NetworkManager, assigned until the NetworkObject itself was considered spawned and the NetworkBehaviour had its OnNetworkSpawn method invoked.

The best way to handle netcode specific script within a common update method (FixedUpdate, Update, and LateUpdate) is to just exit early if IsSpawned is false. This way, any checks for things like IsServer, IsHost, or IsClient that proceed the IsSpawned check (i.e. it is true/spawned) will be guaranteed to be set to the local NetworkManager’s current setting.