Version information

itemswapper-fabric-0.6.0-mc1.20.4

Other relevant installed mods

fabric-api-0.97.0+1.20.4

Expected Behavior

Login to Server with mod installed on both Client and Server

Actual Behavior

Crash with log error:

[17:09:55] [Server thread/ERROR]: Couldn't place player in world java.lang.RuntimeException: Cannot load class net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking$PlayChannelHandler in environment type SERVER at net.fabricmc.loader.impl.transformer.FabricTransformer.transform(FabricTransformer.java:59) ~[fabric-loader-0.15.10.jar:?] at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPreMixinClassByteArray(KnotClassDelegate.java:462) ~[fabric-loader-0.15.10.jar:?] at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:415) ~[fabric-loader-0.15.10.jar:?] at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.tryLoadClass(KnotClassDelegate.java:323) ~[fabric-loader-0.15.10.jar:?] at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.loadClass(KnotClassDelegate.java:218) ~[fabric-loader-0.15.10.jar:?] at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:119) ~[fabric-loader-0.15.10.jar:?] at java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[?:?] at net.minecraft.class_3324.handler$zij000$itemswapper$placeNewPlayer(class_3324.java:3011) ~[server-intermediary.jar:?] at net.minecraft.class_3324.method_14570(class_3324.java:282) ~[server-intermediary.jar:?] at net.minecraft.class_8610.method_52408(class_8610.java:128) ~[server-intermediary.jar:?] at net.minecraft.class_8736.method_53043(class_8736.java:20) ~[server-intermediary.jar:?] at net.minecraft.class_8736.method_11054(class_8736.java:7) ~[server-intermediary.jar:?] at net.minecraft.class_2600.method_11072(class_2600.java:24) ~[server-intermediary.jar:?] at net.minecraft.class_3738.run(class_3738.java:18) ~[server-intermediary.jar:?] at net.minecraft.class_1255.method_18859(class_1255.java:156) ~[server-intermediary.jar:?] at net.minecraft.class_4093.method_18859(class_4093.java:23) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_24306(MinecraftServer.java:797) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_18859(MinecraftServer.java:165) ~[server-intermediary.jar:?] at net.minecraft.class_1255.method_16075(class_1255.java:130) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_20415(MinecraftServer.java:779) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_16075(MinecraftServer.java:773) ~[server-intermediary.jar:?] at net.minecraft.class_1255.method_5383(class_1255.java:115) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_16208(MinecraftServer.java:757) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:687) ~[server-intermediary.jar:?] at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:270) ~[server-intermediary.jar:?] at java.lang.Thread.run(Thread.java:833) ~[?:?] [17:09:55] [Server thread/INFO]: ******** lost connection: Invalid player data

Reproduction Steps

Join Server with mod installed on both

Render engine

• Vanilla
• Sodium(optionally with Iris)
• Optifine
• VulkanMod
• Canvas
• Other

Additional information

No response

Releasing at 3:30 am, what could go wrong. But there were a few things horribly wrong in all versions.

Either you are missing the Fabric api on the server, or I messed something up.

Fabric API is on the server, Item Swapper works fine without the shulker support with it off the server and only on client.

Tested with Fabric Versions 0.15.7 and 0.15.10

only mods installed on client and server:

• fabric-api-0.97.0+1.20.4.jar
• itemswapper-fabric-0.6.0-mc1.20.4.jar

Then try downgrading the mod just on the server to the last version. Possible that I messed up something in the networking logic.
Edit:

Tested with Fabric Versions 0.15.7 and 0.15.10

Thats not the fabric API. Install Fabric Api 0.97.0+1.20.4 on it.

Correct, they are the Fabric Loader versions i tried testing with. the API is installed on both server and client.

With itemswapper-fabric-0.5.6-mc1.20.4.jar on server and itemswapper-fabric-0.6.0-mc1.20.4.jar on client it refuses to connect at all.

Ah I think I see what went wrong. I won't be able to fix that right now, spent the past 8 hours releasing versions and updating mods/plugins. 1.20.4 multiplayer you can just use the 0.5.6 version for now(but I heard something is off there too, networking sucks).

no problem, it works for my needs right now without it installed server side.

Thanks,

Oof I see what happened, I have the server and client util methods in the same class. oops. Will have to split that up.

Ok, turns out not only that is an issue, but something else also went horribly wrong. Time for an emergency fix before I go to bed 😅