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Mixin Blacklisting

Mixin Helper provides three levels of blacklisting, each suited for different situations. All blacklisting is configured in the blacklist section of config/mixinhelper.json.

Overview​

LevelWhat It BlocksWhen to Use
Individual MixinsA single mixin classYou know exactly which mixin causes the problem
Mixin ConfigsAll mixins from a config fileYou want to disable an entire mod's mixins
Target ClassesAll mixins targeting a classYou want to protect a specific Minecraft class

Individual Mixin Blacklisting​

Block a specific mixin class by its fully qualified name.

Configuration​

"blacklist": {
  "mixins": [
    "com.example.mod.mixin.MixinLevelRenderer"
  ]
}

How to Find the Mixin Class Name​

  1. Enable the audit log
  2. Launch the game
  3. Open config/mixinhelper-report.json
  4. Search for the mod name or the target class you're investigating
  5. Copy the fully qualified class name from the report

When to Use​

  • A specific mixin from one mod conflicts with another mod
  • You want to disable a single feature without removing the entire mod
  • You've identified the exact mixin causing a crash or bug

Mixin Config Blacklisting​

Block all mixins registered by an entire mixin config file. Most mods have one or two config files (e.g., modid.mixins.json, modid.client.mixins.json).

Configuration​

"blacklist": {
  "mixinConfigs": [
    "examplemod.mixins.json"
  ]
}

How to Find Config Names​

The audit report lists every loaded mixin config by name:

{
  "name": "examplemod.mixins.json",
  "packageName": "com.example.examplemod.mixin",
  "priority": 1000,
  "mixins": [
    {"className": "com.example.examplemod.mixin.MixinOne", "side": "common"},
    {"className": "com.example.examplemod.mixin.MixinTwo", "side": "common"},
    {"className": "com.example.examplemod.mixin.MixinThree", "side": "client"}
  ]
}

The name field is what you add to the blacklist.

When to Use​

  • A mod's mixins are broadly incompatible with your modpack
  • You want to disable all of a mod's behavior modifications at once
  • The mod has many mixins and blacklisting them individually would be tedious
note

Blacklisting a mixin config does not uninstall the mod. The mod's other features (items, blocks, etc.) will still load — only its mixin-based behavior modifications are disabled.

Target Class Blacklisting​

Prevent any mixin — from any mod — from applying to specific Minecraft classes.

Configuration​

"blacklist": {
  "targetClasses": [
    "net.minecraft.world.level.Level",
    "net.minecraft.client.renderer.LevelRenderer"
  ]
}

When to Use​

  • Multiple mods conflict when they all mixin into the same class
  • You want to protect a vanilla class from all modifications
  • You're debugging which class is causing instability
Broad Impact

Target class blacklisting affects all mods. If Mod A and Mod B both mixin into Level, blacklisting Level blocks both. For finer control, use individual mixin blacklisting instead.

Combining Blacklists​

All three blacklist levels work together. You can use them in any combination:

"blacklist": {
  "mixins": [
    "com.moda.mixin.MixinSpecificProblem"
  ],
  "mixinConfigs": [
    "problematicmod.mixins.json"
  ],
  "targetClasses": [
    "net.minecraft.world.level.Level"
  ]
}

A mixin is blocked if it matches any of the three blacklists.

Verifying Blacklists​

To confirm your blacklist is working:

  1. Set debug.logBlacklistActions to true (it's on by default)
  2. Launch the game
  3. Check the game log for [MixinHelper] messages confirming each blacklisted mixin
[MixinHelper] Blacklisted mixin: com.moda.mixin.MixinSpecificProblem
[MixinHelper] Blacklisted mixin config: problematicmod.mixins.json

Next Steps​