JAR hell
- HexNicks
This is an error they need to fix, as explained below.
Your Minecraft server comes with many utility libraries. Some plugin developers use them in writing their plugins, however they include them in their plugin jar in a wrong way, causing conflicts.
For example, the Adventure library is shipped since Paper 1.16 in the server jar. Its Java package, the unique location, is "net.kyori.adventure".
When you're developing a plugin, there's no need to include Adventure if you only plan to support Paper 1.16. However, should you wish to support Spigot, or legacy Minecraft versions, you need to bundle the library in your jar.
However, if you bundle it as-is, meaning you don't relocate its package to for example "me.myname.net.kyori.adventure" but leave it as "net.kyori.adventure", and the server already comes with the library with its original location of "net.kyori.adventure", bad things will happen, called "JAR hell".
The Java compiler will not be able to determine which version of the library it's being called should another plugin use it and cause conflicts. This is made worse by developers even shipping an outdated library in their plugin without relocation, which can crash ChatControl.
Here is an example of ChatControl loading with HexNicks plugin on legacy server version, this is how a crash will appear in the game console:
Upon decompiling HexNicks, we found it shaded an outdated Adventure library without relocation (the path "net.kyori.adventure" should have been changed). Java compiler has thus given ChatControl the outdated library to use, leading to its crash:
Here is an example of DiscordSRV, a well-made plugin shading the Adventure library in a relocated package, meaning ChatControl will properly use the official version of the library and Java knows that it should only serve DiscordSRV the library it ships with:
Plugin developers need to configure their favorite tool like Maven or Gradle to relocate the dependencies they shade into a unique package, ideally prefixed with their own package name.
- Maven class relocation: https://maven.apache.org/plugins/maven-shade-plugin/examples/class-relocation.html
- Gradle task relocation: https://gradleup.com/shadow/configuration/relocation/