Spawn Recursion Guard

Spawn Recursion Guard (Forge 1.20.1)

Spawn Recursion Guard is a lightweight Forge utility mod designed to protect modded worlds from recursive entity spawn loops — a class of bugs where entity spawn logic unintentionally triggers itself repeatedly, leading to server crashes such as StackOverflowError or “Exception ticking world”.

This mod does not change normal mob spawning, difficulty scaling, or gameplay balance.
It only activates when a spawn occurs during an active spawn call chain, preventing infinite recursion while allowing the original spawn to complete normally.

What this mod does

• Adds a low-level re-entrancy guard to entity spawning

• Prevents “spawn → spawn → spawn → …” recursion loops

• Works automatically — no configuration required

• Safe to add to existing worlds

• Server-side only (clients do not need it)

What this mod does not do

• Does not limit normal spawn rates

• Does not cap mob counts

• Does not disable features from other mods

• Does not modify or redistribute any other mod’s code

When should you use this?

This mod is useful if you experience crashes involving:

• EntityJoinLevelEvent

• /summon being called repeatedly

• Stack traces that repeat spawn-related methods

• Interactions between multiple difficulty / AI / mob enhancement mods

It is especially helpful in large or experimental modpacks where many mods react to entity spawns.

Compatibility & Ethics

• This mod contains only original code

• It does not bundle or modify any other mod

• It uses standard Forge and Mixin techniques at runtime

• Not affiliated with or endorsed by any other mod authors