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