Update PluginMessageMessenger.java

[ghost]

Verify the event is cancelled

[lucko]

Is this addressing a particular bug? It shouldn't be necessary to check for cancellations - other plugins should have no reason to cancel our messages - and if they do, then they should probably be cancelled via the LuckPerms events.

[linsaftw]

Hi, plugins like ExploitFixer limit the amount of PluginMessages because players can spam them with stuff like books/custompayload to cause the server to crash, and it is a good practice to always check that events are cancelled, it makes other developers life a pain when developers don't ignore on cancellation.

Cancellation is super important and has to be done before anything else is done, join event is important to be properly cancelled too as machines can be used to spam connections.

Anyways, why do you want to run LuckPerms when it's cancelled?

[lucko]

Messages sent from players are ignored:

https://github.com/lucko/LuckPerms/blob/7d47b31bcb0502e5137494910b4e061d7040be16/bungee/src/main/java/me/lucko/luckperms/bungee/messaging/PluginMessageMessenger.java#L96-L98

They're only accepted in the other "direction" - from the backend server. It would therefore not be possible for a malicious user to exploit/packet spam this system.

It is good practice to consider whether events are cancelled and how to react when that is the case. It is not good practice to blindly ignore cancelled events always - otherwise that would just be the default behaviour, wouldn't it?

The reason for not ignoring cancelled events in this case was explained in my previous response:

It shouldn't be necessary to check for cancellations - other plugins should have no reason to cancel our messages - and if they do, then they should probably be cancelled via the LuckPerms events.