CObblemon:CRZquiz

The bug was in RewardManager.giveRewards() — two issues:

1. transactionId was just the player's UUID (line 32): Since the transaction ID never changed between quizzes, the anti-dupe check at line 45 would permanently block the player after their first win.
2. cleanup() was called only at the end (line 86): When a player got blocked by the transaction check, the method returned early at line 47, so cleanup() was never reached and the stale entry was never removed.

Fix applied:

• Changed transactionId from playerId.toString() to playerId + "-" + System.currentTimeMillis(), making it unique per reward event instead of per player. This way the anti-dupe check only prevents the same reward call from being processed twice simultaneously, without blocking future quizzes.
• Moved cleanup() to the beginning of the method, before any checks, so stale entries are always cleared regardless of early returns.

English support

CRZquiz is a server-side Fabric mod for Minecraft 1.21.1 that runs an automatic Pokemon trivia quiz system with Cobblemon item rewards.

How it works:

• At a configurable interval (default: every 5 minutes), a random Pokemon question is broadcast to all online players
• Players answer by typing directly in chat (e.g. "Charmander")
• The first player to answer correctly wins prizes; wrong answers are tracked too
• If nobody answers within the time limit (default: 30 seconds), the correct answer is revealed

Rewards (Cobblemon items):

• Pokeballs (always) — weighted random selection from 12 types (Poke Ball, Great Ball, Ultra Ball, Premier, Luxury, etc.)
• Rare Candy — 10% chance per quiz win
• Relic Coins — 10% chance, random amount (1-64)

Features:

• 150+ Pokemon questions in 4 difficulty levels (Easy, Medium, Hard, Ultra)
• Per-player stats tracking (correct/wrong answers, accuracy %)
• Global leaderboard (/quiz top) with medals for top 3
• Sound effects on quiz start, correct answer, and timeout
• Anti-duplication system with cooldowns and transaction IDs
• Fully configurable via JSON files (intervals, rewards, messages, pokeball weights)

Commands:

• /quiz stats — View your personal quiz stats
• /quiz top — View the server leaderboard
• /quiz help — Show available commands
• /crzquiz start/stop — Start/stop the quiz system (OP only)
• /crzquiz force — Force-start a quiz immediately (OP only)
• /crzquiz reload — Reload all config files (OP only)