ShulkerProxyAgent fails to load on BungeeCord (VerifyError: Bad return type with Protobuf) #1116
Description
What happened?
When starting BungeeCord with ShulkerProxyAgent, the plugin fails to load with a java.lang.VerifyError.
It seems related to a Protobuf incompatibility (GeneratedMessage vs GeneratedMessageV3).
What components are involved in your issue?
Proxy Agent (BungeeCord)
Version
0.13.0
Kubernetes Version
1.33.1
Relevant log output
[init] Resolving type given BUNGEECORD
[mc-image-helper] 00:51:30.767 INFO : Downloaded /server/BungeeCord-1999.jar
[init] Setting initial memory to 512m and max to 512m
Sep 19, 2025 12:51:31 AM org.jline.utils.Log logr
WARNING: Unable to create a system terminal, creating a dumb terminal (enable debug logging for more information)
00:51:31 [INFO] Using mbed TLS based native cipher.
00:51:31 [INFO] Using zlib based native compressor.
00:51:31 [INFO] Enabled BungeeCord version git:BungeeCord-Bootstrap:1.21-R0.4-SNAPSHOT:01048b4:1999
00:51:31 [INFO] Not on Windows, attempting to use enhanced EpollEventLoop
00:51:31 [INFO] Epoll is working, utilising it!
00:51:31 [INFO] Discovered module: ModuleSpec(name=cmd_alert, file=modules/cmd_alert.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Discovered module: ModuleSpec(name=cmd_find, file=modules/cmd_find.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Discovered module: ModuleSpec(name=cmd_list, file=modules/cmd_list.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Discovered module: ModuleSpec(name=cmd_send, file=modules/cmd_send.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Discovered module: ModuleSpec(name=cmd_server, file=modules/cmd_server.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Discovered module: ModuleSpec(name=reconnect_yaml, file=modules/reconnect_yaml.jar, provider=JenkinsModuleSource())
00:51:31 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:31 [INFO] Attempting to Jenkins download module cmd_alert v1999
00:51:32 [INFO] Download complete
00:51:32 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:32 [INFO] Attempting to Jenkins download module cmd_find v1999
00:51:32 [INFO] Download complete
00:51:32 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:32 [INFO] Attempting to Jenkins download module cmd_list v1999
00:51:32 [INFO] Download complete
00:51:32 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:32 [INFO] Attempting to Jenkins download module cmd_send v1999
00:51:33 [INFO] Download complete
00:51:33 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:33 [INFO] Attempting to Jenkins download module cmd_server v1999
00:51:33 [INFO] Download complete
00:51:33 [INFO] Attempting to update plugin from null to ModuleVersion(build=1999, git=01048b4)
00:51:33 [INFO] Attempting to Jenkins download module reconnect_yaml v1999
00:51:33 [INFO] Download complete
00:51:33 [INFO] Loaded plugin reconnect_yaml version git:reconnect_yaml:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Loaded plugin cmd_find version git:cmd_find:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Loaded plugin cmd_server version git:cmd_server:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Loaded plugin ShulkerProxyAgent version 0.13.0 by Jérémy Levilain <[email protected]>
00:51:33 [INFO] Loaded plugin cmd_alert version git:cmd_alert:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Loaded plugin cmd_send version git:cmd_send:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Loaded plugin cmd_list version git:cmd_list:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [WARNING] Forced host server pvp is not defined
00:51:33 [INFO] Enabled plugin reconnect_yaml version git:reconnect_yaml:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Enabled plugin cmd_find version git:cmd_find:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Enabled plugin cmd_server version git:cmd_server:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [WARNING] Exception encountered when loading plugin: ShulkerProxyAgent
java.lang.VerifyError: Bad return type
Exception Details:
Location:
com/agones/dev/sdk/Empty.internalGetFieldAccessorTable()Lcom/google/protobuf/GeneratedMessage$FieldAccessorTable; @4: areturn
Reason:
Type 'com/google/protobuf/GeneratedMessageV3$FieldAccessorTable' (current frame, stack[0]) is not assignable to 'com/google/protobuf/GeneratedMessage$FieldAccessorTable' (from method signature)
Current Frame:
bci: @4
flags: { }
locals: { 'com/agones/dev/sdk/Empty' }
stack: { 'com/google/protobuf/GeneratedMessageV3$FieldAccessorTable' }
Bytecode:
0000000: 2ab6 008d b0
at com.agones.dev.sdk.AgonesSDKImpl.<clinit>(AgonesSDKImpl.java:16)
at io.shulkermc.proxyagent.ShulkerProxyAgentCommon.onProxyInitialization(ShulkerProxyAgentCommon.kt:53)
at io.shulkermc.proxyagent.bungeecord.ShulkerProxyAgentBungeeCord.onEnable(ShulkerProxyAgentBungeeCord.kt:18)
at net.md_5.bungee.api.plugin.PluginManager.enablePlugins(PluginManager.java:301)
at net.md_5.bungee.BungeeCord.start(BungeeCord.java:302)
at net.md_5.bungee.BungeeCordLauncher.main(BungeeCordLauncher.java:69)
at net.md_5.bungee.Bootstrap.main(Bootstrap.java:15)
00:51:33 [INFO] Enabled plugin cmd_alert version git:cmd_alert:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Enabled plugin cmd_send version git:cmd_send:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
00:51:33 [INFO] Enabled plugin cmd_list version git:cmd_list:1.21-R0.4-SNAPSHOT:01048b4:1999 by SpigotMC
>
00:51:33 [INFO] Listening on /0.0.0.0:25577
>00:52:46 [INFO[] Closing listener [id: 0x38faae85, L:/[0:0:0:0:0:0:0:0]:25577]
00:52:46 [INFO] Closing pending connections
00:52:46 [INFO] Disconnecting 0 connections
00:52:47 [INFO] Disabling plugins
00:52:47 [SEVERE] Exception disabling plugin ShulkerProxyAgent
kotlin.UninitializedPropertyAccessException: lateinit property cache has not been initialized
at io.shulkermc.proxyagent.ShulkerProxyAgentCommon.getCache(ShulkerProxyAgentCommon.kt:38)
at io.shulkermc.proxyagent.ShulkerProxyAgentCommon.shutdown(ShulkerProxyAgentCommon.kt:110)
at io.shulkermc.proxyagent.ShulkerProxyAgentCommon.onProxyShutdown(ShulkerProxyAgentCommon.kt:106)
at io.shulkermc.proxyagent.bungeecord.ShulkerProxyAgentBungeeCord.onDisable(ShulkerProxyAgentBungeeCord.kt:28)
at net.md_5.bungee.BungeeCord.independentThreadStop(BungeeCord.java:484)
at net.md_5.bungee.BungeeCord.access$000(BungeeCord.java:95)
at net.md_5.bungee.BungeeCord$3.run(BungeeCord.java:328)
00:52:47 [INFO] Closing IO threads
00:52:49 [INFO] Thank you and goodbye
stream closed EOF for shulker-test/public-n4hwk-lzlmf (proxy)Code of Conduct
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