Root cause: auto-save BG task queued before logout could acquire bgLock and write a stale snapshot AFTER the logout BG task had committed fresh data + online=0. On reconnect, the stale inventory was restored while the dropped ItemEntity remained on the ground -> duplication. Three-layer guard applied to onPlayerSaveToFile and onLivingDeath BG tasks: 1. Early skip if pendingLogoutSaves contains the player (before tryLock) 2. Re-check pendingLogoutSaves after acquiring bgLock (race window) 3. SELECT online from player_data before write; skip if online=0 Logout BG task now acquires bgLock via .lock() (blocking) so concurrent auto-save / death-save tasks using tryLock either skip cleanly or wait. removePlayerLock reordered before bgLock.unlock so late auto-save BGs see containsKey=false and skip. |
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| .github | ||
| compat-mods | ||
| gradle/wrapper | ||
| src/main | ||
| .gitattributes | ||
| .gitignore | ||
| build.gradle | ||
| docker-compose.yml | ||
| gradle.properties | ||
| gradlew | ||
| gradlew.bat | ||
| LICENSE | ||
| README.md | ||
| settings.gradle | ||
PlayerSync
PlayerSync is a Minecraft Forge mod that synchronizes player data across multiple servers using a MySQL backend. It allows players to maintain their inventory, equipment, experience, advancements, and more when moving between servers in a network.
Mod Support
Any other mods support is also possible.
Development Setup
Database Setup (Docker)
A docker-compose.yml file is provided for easily setting up a MariaDB database instance for development testing.
- Make sure Docker is installed.
- Inside your work directory run:
This will download the MariaDB image (if not already present) and start a database container in the background.docker compose up -d - Stoppinng the Database
docker compose down
Data Persistence: The database uses a Docker volume, ensuring your data persists even if you stop and restart the containers.
Database Management Tool
The docker-compose.yml also includes an Adminer service, a lightweight database management tool.
- Access Adminer in your web browser at http://localhost:8080.
- Log in using the server with
- username:
playersync - database:
playersync - password: see docker-compose.yml
- username:
For debugging purposes, you can enable use_legacy_serialization to have readable database fields. This can cause crashes and unintended side-effects. Do not enable this on a production server if not absolutely necessary!
Running the Mod
The project uses Gradle for building and running. Use the provided Gradle wrapper (gradlew for Linux/macOS, gradlew.bat for Windows).
- Make sure that the MySQL database you configured is running.
- Run the Server
or on Windows:./gradlew runServer
This task compiles the mod and starts a dedicated Minecraft server instance with the mod loaded in the.\gradlew.bat runServerrundirectory. - Run the Client
or on Windows:./gradlew runClient.\gradlew.bat runClient