Floodgate Loader constraint violation when using getLinkedPlayer() API method

When using the Floodgate API, if Geyser and Floodgate are both installed on the proxy, the following exception is thrown whenever getLinkedPlayer() is called:

[19:33:24 WARN]: Error dispatching event PostLoginEvent(player=.Kopo942) to listener com.djrapitops.extension.FloodgateBungeeListener@4b8a0d03
java.lang.LinkageError: loader constraint violation: when resolving interface method 'org.geysermc.floodgate.util.LinkedPlayer org.geysermc.floodgate.api.player.FloodgatePlayer.getLinkedPlayer()' the class loader net.md_5.bungee.api.plugin.PluginClassloader @74db12c2 of the current class, com/djrapitops/extension/FloodgateBungeeListener, and the class loader net.md_5.bungee.api.plugin.PluginClassloader @1286528d for the method's defining class, org/geysermc/floodgate/api/player/FloodgatePlayer, have different Class objects for the type org/geysermc/floodgate/util/LinkedPlayer used in the signature (com.djrapitops.extension.FloodgateBungeeListener is in unnamed module of loader net.md_5.bungee.api.plugin.PluginClassloader @74db12c2, parent loader 'app'; org.geysermc.floodgate.api.player.FloodgatePlayer is in unnamed module of loader net.md_5.bungee.api.plugin.PluginClassloader @1286528d, parent loader 'app')
        at com.djrapitops.extension.FloodgateBungeeListener.onLogin(FloodgateBungeeListener.java:62) ~[?:?]
        at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
        at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[?:?]
        at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
        at java.lang.reflect.Method.invoke(Method.java:567) ~[?:?]
        at net.md_5.bungee.event.EventHandlerMethod.invoke(EventHandlerMethod.java:19) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at net.md_5.bungee.event.EventBus.post(EventBus.java:48) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at net.md_5.bungee.api.plugin.PluginManager.callEvent(PluginManager.java:466) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at net.md_5.bungee.connection.InitialHandler$6$1.run(InitialHandler.java:549) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:497) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[waterfall-1.17-443.jar:git:Waterfall-Bootstrap:1.17-R0.1-SNAPSHOT:34188b3:443]
        at java.lang.Thread.run(Thread.java:831) [?:?]

As discussed on Discord, this seems to be a known issue. Probably not limited to the LinkedPlayer class, but instead to all classes in the org.geysermc.floodgate.util package.

Jul 14 '21 16:07 AnttiMK

This should have been fixed with https://github.com/GeyserMC/Geyser/commit/b2619fa7c79e58fea9e05c68a5bd7a9ecc2b5f46, are you not up to date?

Jul 15 '21 00:07 Chew

That commit did not fix that error message. It was ignored as I believe the error belongs in Floodgate. Conversation was had about the issue in #development earlier today.