Hotload breaks games that use Network

[PolSpock]

Describe the bug

Hi,

Since the resolution of https://github.com/sboxgame/issues/issues/4066, the hotload for games that used [Net] var was fixed. However, as @MrBrax notices, hotload recently restarting creates errors.

Now it's generally random but I've been able to recreate a scenario for having the error frequently. See below.

To Reproduce

I've been able to bring you an easy way to reproduce : 1) Download & mount sbox-gunfight https://github.com/Facepunch/sbox-gunfight/ 2) Start "FFA - Small Town" 3) Hotload the game by editing & saving a GameResource extended class. Like sbox-gunfight-main\code\WeaponSystem\WeaponDefinition.cs, just add a function to the class :

public void Hello()
{
    Log.Info( "I will break the game" );
}

4) The game starts to be crazy: you cannot play anymore with this spamming console error :

Could not proxy var 196671 as it does not exist in the network table
   at Sandbox.Internal.VarClass`1.Read(NetRead reader)
   at Sandbox.Internal.Var.Read()
   at Sandbox.NetworkTable.ReadAll(PredictionDataStore prediction)
   at Sandbox.Entity.UpdateFromNetwork()
   at Sandbox.Entity.PredictionStore(Int32 slot, Int32 command_num, Boolean network, Boolean variables)
   at Managed.SourceClient.Exports.Sandbox_Entity_PredictionStore(UInt32 self, Int32 slot, Int32 command, Int32 network, Int32 notnetworked)
   at NativeEngine.EngineGlobal.SourceEngineFrame(CMaterialSystem2AppSystemDict appDict, Double currentTime, Double previousTime)
   at Sandbox.EngineLoop.RunFrame(CMaterialSystem2AppSystemDict appDict, Boolean& wantsQuit)
   at Sandbox.SourceEngineApp.RunFrame() in C:\build\_work\sbox\sbox\engine\Launcher\SourceEngineApp.cs:line 46
   at Sandbox.SourceEngineApp.RunLoop() in C:\build\_work\sbox\sbox\engine\Launcher\SourceEngineApp.cs:line 37
   at Sandbox.Program.LaunchGame() in C:\build\_work\sbox\sbox\engine\Launcher\Launcher.cs:line 108
   at Sandbox.Program.Main() in C:\build\_work\sbox\sbox\engine\Launcher\Launcher.cs:line 58

And the HUD of GameMenu will be broken

The sandbox game doesn't have this issue, so i conclude that network replication on hotload is currently broken

Expected behavior

Hotload must not breaking game

Media/Files

No response

Additional context

No response

[MrBrax]

Now it's even worse, completely breaking input and spamming the server console

[PolSpock]

Something has changed since this update, is more stable for me

[MrBrax]

Same. Network vars seem to be fixed but menu still breaks.

[Xartrick]

Same. Network vars seem to be fixed but menu still breaks.

Menu breaking on hotload is something I experienced. Here is how I fixed it.

1. OnAfterTreeRender(true) is not called when hotloading, something to keep in mind ;
2. @ref might be null on reload, you must manually check them ;
3. Check if your input variables are not null by using "guards".

Minimal example with a random component that expects a Player input :

@using Sandbox;
@using Sandbox.UI;

// guard
@if (Player == null) {
    return;
}

<root>
    <h1>@(Player.Name)</h1>
    <div @ref=ProgressBar></div>
</root>

@code
{
    // inputs
    public Player Player { get; set; }

    // references
    private Panel ProgressBar { get; set; }

    // properties
    private bool IsInitialized => ProgressBar != null;

    public override void Tick()
    {
        if (!IsInitialized) {
            return;
        }

        var progress = 0f; // calculate some progress
        ProgressBar.Style.Width = Length.Percent(progress);
    }
}