xDupe

# xDupe **xDupe** is a lightweight, open-source Paper plugin that brings back the classic piston-item frame duplication mechanic for anarchy servers. Originally patched by both Mojang and Paper, this mechanic is carefully re-implemented to bypass modern anti-dupe protections while keeping full NBT integrity. Fully configurable via both file and in-game commands. - **Author:** EMIRLQQ1 - **Language:** Java 17+ - **Platform:** Paper 1.20 – 1.21.x (Spigot API) - **License:** MIT --- ## Table of Contents - (#features) - (#how-it-works) - (#installation) - (#configuration) - (#commands) - (#permissions) - (#building-from-source) - (#supported-versions) - (#troubleshooting) - (#faq) - (#notes) - (#license) --- ## Features - **Classic Dupe Mechanic** – Piston extends into an item frame → item is duplicated. Works exactly like the pre-1.20 vanilla behavior, but better. - **Glow Item Frame Support** – Fully compatible with both normal item frames and glow item frames. - **Full NBT Preservation** – Enchantments, custom names, lore, attributes, potion effects, and all other NBT data are preserved on every duplicated item. - **Configurable Chance** – Set the duplication success rate from 0% to 100%. When the chance fails, the item frame breaks naturally as if nothing happened. - **Configurable Amount** – Control how many extra copies are dropped. Set to 0 for no duplication at all, or set high values for extreme duplication. - **Configurable Frame Drop** – Choose whether the item frame itself drops as an item when broken. - **In-Game Configuration** – Change all settings on the fly with simple commands. No server restarts required. - **Tab Completion** – Full tab completion support for every command and value. - **Anti-Anti-Dupe** – Runs at `EventPriority.LOWEST` and removes the item frame instantly to prevent anti-cheat plugins from interfering. - **Performance Optimized** – Uses `getNearbyEntities` with bounding box filtering instead of scanning the entire world. Minimal overhead. - **Adventure API** – Built with Paper's modern Adventure API for reliable cross-version chat formatting. --- ## How It Works ``` ┌─────────────────────┐ │ Piston Extends │ └──────────┬──────────┘ │ ┌──────────v──────────┐ │ Item Frame Found │ │ in front of piston │ └──────────┬──────────┘ │ ┌──────────v──────────┐ │ Frame has item? │ └──────┬──────────┬───┘ │ │ yes no │ │ ┌──────────v──┐ │ │ Chance │ │ │ Check │ │ └──────┬──────┘ │ │ │ ┌───────┴───────┐ │ │ │ │ success failed │ │ │ │ ┌───────v───────┐ │ │ │ Drop original │ │ │ │ + extra copies │ │ │ │ (+ frame if │ │ │ │ enabled) │ │ │ └───────┬───────┘ │ │ │ │ │ ┌───────v───────┐ │ │ │ Remove frame │ │ │ │ from world │ │ │ └───────┬───────┘ │ │ │ │ │ └──────┬───────┘ │ │ │ ┌──────v──────┐ │ │ Done │ │ └────────────┘ │ ┌──────────v──────────┐ │ Natural Break │ │ (vanilla behavior) │ └─────────────────────┘ ``` ### Technical Details When a piston extends, the server fires a `BlockPistonExtendEvent`. xDupe listens at `EventPriority.LOWEST` — before any anti-cheat or anti-dupe plugin has a chance to cancel the event. At this point: 1. The plugin calculates the block position the piston head will occupy. 2. It searches for item frames at that exact block location using a bounding box query (`getNearbyEntities` with 0.75 radius). 3. If an item frame with an item is found, the configured chance is rolled. 4. On success: the item is cloned with `ItemStack.clone()`, which copies all NBT data including enchantments, custom n