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[BUG] Mod Fails to Initialize on Dedicated Server due to Client-Side Mixin

Summary

Hello, I'm experiencing an issue where the mod fails to properly initialize on a dedicated server, resulting in no trainers spawning. This happens even with a minimal installation (Fabric API, Architectury, Cloth Config, Cobblemon, RCT API, RCT Mod) normally I use the Cobbleverse modpack and I had the issue when starting a server. The issue seems to stem from a client-side mixin being applied on the server, which fails and puts the mod in a broken state. The log shows this sequence of errors: A WARN appears first: @mixin target net.minecraft.class_918 was not found rctmod.mixins.json:client.ItemRendererMixin from mod rctmod This is immediately followed by an ERROR: No data fixer registered for trainer and trainer_association. This indicates the ItemRendererMixin failure prevents the proper registration of trainers, leading to no natural spawns and Invalid trainer id errors when spawning them manually. The mod works perfectly in a single-player environment with the same setup. This appears to be a packaging issue where a client-only mixin is not disabled on the server side."

Steps to reproduce

launch a dedicated server with these versions of the mod :

Mods and Versions

architectury-13.0.8-fabric.jar Cobblemon_MegaShowdown-9.7.11-release-fabric.jar rctapi-fabric-1.21.1-0.13.6-beta.jar cloth-config-15.0.140-fabric.jar fabric-api-0.116.3+1.21.1.jar rctmod-fabric-1.21.1-0.16.5-beta.jar Cobblemon-fabric-1.6.1+1.21.1.jar ForgeConfigAPIPort-v21.1.3-1.21.1-Fabric.jar trinkets-3.10.0.jar

What is the current bug behavior?

I don't get the starter pack when choosing my starter and no trainers are loaded

What is the expected correct behavior?

the exact oposit

Relevant logs and/or screenshots

minecraft@mc-modded-server:~/1_CobbleVerse_Ultimate$ ./start.sh 
Starting net.fabricmc.loader.impl.game.minecraft.BundlerClassPathCapture
[15:29:47] [main/INFO]: Loading Minecraft 1.21.1 with Fabric Loader 0.16.14
[15:29:47] [main/WARN]: Warnings were found!
 - Mod 'Forge Config API Port' (forgeconfigapiport) 21.1.3 recommends any version of modmenu, which is missing!
	 - You should install any version of modmenu for the optimal experience.
[15:29:47] [main/INFO]: Loading 67 mods:
	- architectury 13.0.8
	- cloth-config 15.0.140
	   \-- cloth-basic-math 0.6.1
	- cobblemon 1.6.1+1.21.1
	   \-- fabric-language-kotlin 1.11.0+kotlin.2.0.0
	        |-- org_jetbrains_kotlin_kotlin-reflect 2.0.0
	        |-- org_jetbrains_kotlin_kotlin-stdlib 2.0.0
	        |-- org_jetbrains_kotlin_kotlin-stdlib-jdk7 2.0.0
	        |-- org_jetbrains_kotlin_kotlin-stdlib-jdk8 2.0.0
	        |-- org_jetbrains_kotlinx_atomicfu-jvm 0.24.0
	        |-- org_jetbrains_kotlinx_kotlinx-coroutines-core-jvm 1.8.1
	        |-- org_jetbrains_kotlinx_kotlinx-coroutines-jdk8 1.8.1
	        |-- org_jetbrains_kotlinx_kotlinx-datetime-jvm 0.6.0
	        |-- org_jetbrains_kotlinx_kotlinx-serialization-cbor-jvm 1.6.3
	        |-- org_jetbrains_kotlinx_kotlinx-serialization-core-jvm 1.6.3
	        \-- org_jetbrains_kotlinx_kotlinx-serialization-json-jvm 1.6.3
	- fabric-api 0.116.3+1.21.1
	   |-- fabric-api-base 0.4.42+6573ed8c19
	   |-- fabric-api-lookup-api-v1 1.6.71+b559734419
	   |-- fabric-biome-api-v1 13.0.31+d527f9fd19
	   |-- fabric-block-api-v1 1.1.0+0bc3503219
	   |-- fabric-block-view-api-v2 1.0.11+ebb2264e19
	   |-- fabric-blockrenderlayer-v1 1.1.52+0af3f5a719
	   |-- fabric-client-tags-api-v1 1.1.15+6573ed8c19
	   |-- fabric-command-api-v1 1.2.49+f71b366f19
	   |-- fabric-command-api-v2 2.2.28+6ced4dd919
	   |-- fabric-commands-v0 0.2.66+df3654b319
	   |-- fabric-content-registries-v0 8.0.19+b559734419
	   |-- fabric-convention-tags-v1 2.1.5+7f945d5b19
	   |-- fabric-convention-tags-v2 2.11.1+a406e79519
	   |-- fabric-crash-report-info-v1 0.2.29+0af3f5a719
	   |-- fabric-data-attachment-api-v1 1.4.5+6116a37819
	   |-- fabric-data-generation-api-v1 20.2.31+16c4ae2519
	   |-- fabric-dimensions-v1 4.0.0+6fc22b9919
	   |-- fabric-entity-events-v1 1.8.0+2b27e0a419
	   |-- fabric-events-interaction-v0 0.7.13+ba9dae0619
	   |-- fabric-game-rule-api-v1 1.0.53+6ced4dd919
	   |-- fabric-item-api-v1 11.1.1+d5debaed19
	   |-- fabric-item-group-api-v1 4.1.7+def88e3a19
	   |-- fabric-key-binding-api-v1 1.0.47+0af3f5a719
	   |-- fabric-keybindings-v0 0.2.45+df3654b319
	   |-- fabric-lifecycle-events-v1 2.6.0+0865547519
	   |-- fabric-loot-api-v2 3.0.15+3f89f5a519
	   |-- fabric-loot-api-v3 1.0.3+3f89f5a519
	   |-- fabric-message-api-v1 6.0.14+8aaf3aca19
	   |-- fabric-model-loading-api-v1 2.0.0+fe474d6b19
	   |-- fabric-networking-api-v1 4.3.0+c7469b2119
	   |-- fabric-object-builder-api-v1 15.2.1+40875a9319
	   |-- fabric-particles-v1 4.0.2+6573ed8c19
	   |-- fabric-recipe-api-v1 5.0.14+248df81c19
	   |-- fabric-registry-sync-v0 5.3.1+e3eddc2119
	   |-- fabric-renderer-api-v1 3.4.0+c705a49c19
	   |-- fabric-renderer-indigo 1.7.0+c705a49c19
	   |-- fabric-renderer-registries-v1 3.2.68+df3654b319
	   |-- fabric-rendering-data-attachment-v1 0.3.49+73761d2e19
	   |-- fabric-rendering-fluids-v1 3.1.6+1daea21519
	   |-- fabric-rendering-v0 1.1.71+df3654b319
	   |-- fabric-rendering-v1 5.0.5+df16efd019
	   |-- fabric-resource-conditions-api-v1 4.3.0+8dc279b119
	   |-- fabric-resource-loader-v0 1.3.1+5b5275af19
	   |-- fabric-screen-api-v1 2.0.25+8b68f1c719
	   |-- fabric-screen-handler-api-v1 1.3.90+b559734419
	   |-- fabric-sound-api-v1 1.0.23+6573ed8c19
	   |-- fabric-transfer-api-v1 5.4.3+c24bd99419
	   \-- fabric-transitive-access-wideners-v1 6.2.0+45b9699719
	- fabricloader 0.16.14
	   \-- mixinextras 0.4.1
	- forgeconfigapiport 21.1.3
	   |-- com_electronwill_night-config_core 3.8.0
	   \-- com_electronwill_night-config_toml 3.8.0
	- java 21
	- mega_showdown 9.7.11-release-fabric
	   \-- supermartijn642configlib 1.1.8
	- minecraft 1.21.1
	- rctapi 0.13.6-beta
	- rctmod 0.16.5-beta
	- trinkets 3.10.0
	   |-- cardinal-components-base 6.1.0
	   \-- cardinal-components-entity 6.1.0
[15:29:47] [main/INFO]: SpongePowered MIXIN Subsystem Version=0.8.7 Source=file:/home/minecraft/1_CobbleVerse_Ultimate/libraries/net/fabricmc/sponge-mixin/0.15.5+mixin.0.8.7/sponge-mixin-0.15.5+mixin.0.8.7.jar Service=Knot/Fabric Env=SERVER
[15:29:47] [main/INFO]: Compatibility level set to JAVA_16
[15:29:47] [main/INFO]: Compatibility level set to JAVA_21
[15:29:47] [main/WARN]: Reference map 'forgeconfigapiport.common.refmap.json' for forgeconfigapiport.common.mixins.json could not be read. If this is a development environment you can ignore this message
[15:29:48] [main/WARN]: Reference map 'supermartijn642configlib.mixins.refmap.json' for supermartijn642configlib.mixins.json could not be read. If this is a development environment you can ignore this message
[15:29:48] [main/WARN]: Error loading class: net/minecraft/class_350 (java.lang.ClassNotFoundException: net/minecraft/class_350)
[15:29:48] [main/WARN]: @Mixin target net.minecraft.class_350 was not found mixins.cobblemon-common.json:accessor.EntryListWidgetAccessor from mod cobblemon
[15:29:48] [main/WARN]: Error loading class: juuxel/adorn/block/variant/BlockVariantSets (java.lang.ClassNotFoundException: juuxel/adorn/block/variant/BlockVariantSets)
[15:29:48] [main/WARN]: @Mixin target juuxel.adorn.block.variant.BlockVariantSets was not found mixins.cobblemon-common.json:invoker.AdornRegisterInvoker from mod cobblemon
[15:29:48] [main/WARN]: Error loading class: net/minecraft/class_918 (java.lang.ClassNotFoundException: net/minecraft/class_918)
[15:29:48] [main/WARN]: @Mixin target net.minecraft.class_918 was not found rctmod.mixins.json:client.ItemRendererMixin from mod rctmod
[15:29:48] [main/INFO]: Initializing MixinExtras via com.llamalad7.mixinextras.service.MixinExtrasServiceImpl(version=0.4.1).
[15:29:56] [main/INFO]: Booting LaxPermissionValidator, permissions will be checked using Minecrafts permission level system, see https://minecraft.fandom.com/wiki/Permission_level
[15:29:57] [main/INFO]: Launching Cobblemon 1.6.1 
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:pokemon
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:empty_pokeball
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:boat
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:chest_boat
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:poke_bobber
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:generic_bedrock
[15:29:57] [main/ERROR]: No data fixer registered for cobblemon:npc
[15:29:58] [main/INFO]: Starting the Best Spawner...
[15:29:58] [main/INFO]: Loaded 7 spawning condition types.
[15:29:58] [main/INFO]: Loaded 6 spawning context types.
[15:29:58] [main/INFO]: Loaded 2 spawn detail types.
[15:29:58] [Cobblemon Showdown/INFO]: Starting showdown service...
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/data/moves.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/sim/battle-actions.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/sim/pokemon.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/data/abilities.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/sim/side.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/data/conditions.js
[15:29:58] [Cobblemon Showdown/INFO]: Loaded fallback file: ./showdown/index.js
[15:29:58] [Cobblemon Showdown/INFO]: All files are ready!
[15:30:00] [Cobblemon Showdown/INFO]: Showdown has been started!
[15:30:00] [main/INFO]: Note: Cobblemon data registries are only loaded once per server instance as Pokémon species are not safe to reload.
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/abilities registry
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/moves registry
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/conditions registry
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/held_items registry
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/typecharts registry
[15:30:00] [main/INFO]: Registered the mega_showdown:showdown/scripts registry
[15:30:00] [main/INFO]: Registered the cobblemon:molang registry
[15:30:00] [main/INFO]: Registered the cobblemon:species_features registry
[15:30:00] [main/INFO]: Registered the cobblemon:global_species_features registry
[15:30:00] [main/INFO]: Registered the cobblemon:species_feature_assignments registry
[15:30:00] [main/INFO]: Registered the cobblemon:action_effects registry
[15:30:00] [main/INFO]: Registered the cobblemon:moves registry
[15:30:00] [main/INFO]: Registered the cobblemon:abilities registry
[15:30:00] [main/INFO]: Registered the cobblemon:brain_presets registry
[15:30:00] [main/INFO]: Registered the cobblemon:species registry
[15:30:00] [main/INFO]: Registered the cobblemon:species_additions registry
[15:30:00] [main/INFO]: Registered the cobblemon:pokeballs registry
[15:30:00] [main/INFO]: Registered the cobblemon:properties_tab_completion registry
[15:30:00] [main/INFO]: Registered the cobblemon:spawn_detail_presets registry
[15:30:00] [main/INFO]: Registered the cobblemon:spawn_rules registry
[15:30:00] [main/INFO]: Registered the cobblemon:mechanics registry
[15:30:00] [main/INFO]: Registered the cobblemon:bag_items registry
[15:30:00] [main/INFO]: Registered the cobblemon:dialogues registry
[15:30:00] [main/INFO]: Registered the cobblemon:natural_materials registry
[15:30:00] [main/INFO]: Registered the cobblemon:fossils registry
[15:30:00] [main/INFO]: Registered the cobblemon:npc_preset registry
[15:30:00] [main/INFO]: Registered the cobblemon:npc registry
[15:30:00] [main/INFO]: Registered the cobblemon:dex_entries registry
[15:30:00] [main/INFO]: Registered the cobblemon:dex_entry_additions registry
[15:30:00] [main/INFO]: Registered the cobblemon:dexes registry
[15:30:00] [main/INFO]: Registered the cobblemon:dex_additions registry
[15:30:00] [main/INFO]: Registered the cobblemon:flows registry
[15:30:00] [main/INFO]: Registered the cobblemon:spawn_pool_world registry
[15:30:00] [main/INFO]: Registered the cobblemon:pokerods registry
[15:30:00] [main/INFO]: Registered the cobblemon:berries registry
[15:30:00] [main/INFO]: Registered the cobblemon:fishing_baits registry
[15:30:01] [cobblemon Datafixer Bootstrap/INFO]: 2 Datafixer optimizations took 9 milliseconds
[15:30:01] [main/ERROR]: No data fixer registered for trainer
[15:30:01] [main/ERROR]: No data fixer registered for trainer_association
[15:30:01] [main/INFO]: Environment: Environment[sessionHost=https://sessionserver.mojang.com, servicesHost=https://api.minecraftservices.com, name=PROD]
[15:30:02] [main/WARN]: Missing data pack badgebox
[15:30:02] [main/WARN]: Missing data pack balm
[15:30:02] [main/WARN]: Missing data pack beautify
[15:30:02] [main/WARN]: Missing data pack chipped
[15:30:02] [main/WARN]: Missing data pack cobblecuisine
[15:30:02] [main/WARN]: Missing data pack cobbledollars
[15:30:02] [main/WARN]: Missing data pack cobblefurnies
[15:30:02] [main/WARN]: Missing data pack cobblemonboxlink
[15:30:02] [main/WARN]: Missing data pack cobblenav
[15:30:02] [main/WARN]: Missing data pack cobbleride
[15:30:02] [main/WARN]: Missing data pack comforts
[15:30:02] [main/WARN]: Missing data pack cozyhome
[15:30:02] [main/WARN]: Missing data pack fightorflight
[15:30:02] [main/WARN]: Missing data pack handcrafted
[15:30:02] [main/WARN]: Missing data pack legendarymonuments
[15:30:02] [main/WARN]: Missing data pack lenientdeath
[15:30:02] [main/WARN]: Missing data pack lumymon
[15:30:02] [main/WARN]: Missing data pack pokeblocks
[15:30:02] [main/WARN]: Missing data pack porting_lib_item_abilities
[15:30:02] [main/WARN]: Missing data pack repurposed_structures
[15:30:02] [main/WARN]: Missing data pack server_translations_api
[15:30:02] [main/WARN]: Missing data pack sophisticatedbackpacks
[15:30:02] [main/WARN]: Missing data pack sophisticatedcore
[15:30:02] [main/WARN]: Missing data pack sophisticatedstorage
[15:30:02] [main/WARN]: Missing data pack tmcraft
[15:30:02] [main/WARN]: Missing data pack waystones
[15:30:02] [main/WARN]: Missing data pack cobblemon:repurposedstructurescobblemon
[15:30:03] [main/INFO]: No existing world data, creating new world
[15:30:03] [Worker-Main-1/WARN]: Found loot table element validation problem in {minecraft:loot_table/rctmod:generic/common}.pools[0].entries[6]: Unknown loot table called rctmod:generic/common/evolution
[15:30:03] [Worker-Main-1/WARN]: Found loot table element validation problem in {minecraft:loot_table/rctmod:generic/common}.pools[0].entries[5]: Unknown loot table called rctmod:generic/common/training
[15:30:04] [main/INFO]: Loaded 1975 recipes
[15:30:04] [main/INFO]: Loaded 2195 advancements
[15:30:04] [main/INFO]: Loaded 5 server scripts and 1 client scripts
[15:30:08] [main/INFO]: Loaded 936 moves
[15:30:08] [main/INFO]: Loaded 314 abilities
[15:30:09] [main/INFO]: Finished additions
[15:30:10] [main/INFO]: Imported 259 held item IDs from showdown
[15:30:10] [main/INFO]: Loaded 1025 Pokémon species
[15:30:10] [main/INFO]: Loaded 25 spawn detail presets.
[15:30:10] [main/INFO]: Starting dummy Showdown battle to force it to pre-load data.
[15:30:10] [main/INFO]: Loaded 15 fossils
[15:30:10] [main/ERROR]: Invalid path in mod resource-pack cobblemon: cobblemon:dex_entry_additions/README.md, ignoring
[15:30:10] [main/ERROR]: Invalid path in mod resource-pack cobblemon: cobblemon:dex_additions/README.md, ignoring
[15:30:10] [main/INFO]: Loaded 1 flows and 0 client flows
[15:30:11] [main/INFO]: Loaded 69 berries
[15:30:13] [main/INFO]: Applied 542 biome modifications to 64 of 64 new biomes in 20.99 ms
[15:30:13] [Server thread/INFO]: Starting minecraft server version 1.21.1
[15:30:13] [Server thread/INFO]: Loading properties
[15:30:13] [Server thread/INFO]: Default game type: SURVIVAL
[15:30:13] [Server thread/INFO]: Generating keypair
[15:30:13] [Server thread/INFO]: Starting Minecraft server on *:25565
[15:30:13] [Server thread/INFO]: Using epoll channel type
[15:30:13] [Server thread/INFO]: Preparing level "world"
[15:30:23] [Server thread/INFO]: Preparing start region for dimension minecraft:overworld
[15:30:23] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:24] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:24] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:24] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:25] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:25] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:26] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:26] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:27] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:28] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:28] [Worker-Main-1/INFO]: Preparing spawn area: 2%
[15:30:28] [Worker-Main-1/INFO]: Preparing spawn area: 4%
[15:30:29] [Worker-Main-1/INFO]: Preparing spawn area: 8%
[15:30:29] [Worker-Main-1/INFO]: Preparing spawn area: 8%
[15:30:30] [Worker-Main-1/INFO]: Preparing spawn area: 8%
[15:30:30] [Worker-Main-1/INFO]: Preparing spawn area: 8%
[15:30:31] [Worker-Main-1/INFO]: Preparing spawn area: 8%
[15:30:31] [Server thread/INFO]: Time elapsed: 8412 ms
[15:30:31] [Server thread/INFO]: Done (18.460s)! For help, type "help"
[15:30:31] [Server thread/INFO]: Data pack initialized: rctmod
[15:30:36] [Server thread/INFO]: Registered 1559 trainers