CrossChat

Fixed

• Critical: players kicked with "A proxy plugin caused an illegal protocol state" on Minecraft 1.19.1+
  • Root cause: ChatResult.denied() cannot cancel a cryptographically-signed chat message at the proxy level (Velocity/Minecraft protocol restriction introduced in 1.19.1)
  • Fix: replaced ChatResult.denied() with ChatResult.message(text) which strips the signature (making the message "unsigned") instead of attempting to cancel it — this prevents the disconnect entirely

Added

• crosschat:suppress plugin-message channel — the proxy sends the sender's UUID to the backend over this channel immediately before forwarding the unsigned echo; the companion backend plugin uses this to silently cancel local display
• CrossChatBackend companion Paper plugin (backend/) — drop into each Paper/Purpur backend's plugins/ directory to suppress the local-chat echo of messages already broadcast globally:
  • Listens on crosschat:suppress
  • Cancels AsyncChatEvent for the flagged player via a one-shot ConcurrentHashMap set
  • Compatible with Paper 1.19.1+, Java 17+
  • If the backend plugin is absent, global broadcast still works but the message will also appear in local backend chat

Notes

• In config/paper-global.yml on each backend, ensure enforce-secure-profiles: false so that the signature-stripped message forwarded by Velocity is accepted rather than rejected with a "Chat message delivery failed" system message