[Bug]: Schema.types lazy initialization is not thread-safe

[Splatcrafter]

AI REVIEWED

Module: api
File: api/schema/Schema.java (~line 164-167)
Severity: High

Summary

The lazy initialization of Schema.types uses a bare null-check without synchronization:

if (this.types == null) {
    this.types = this.buildTypes();
}

Multiple threads calling types() concurrently could both pass the null-check and invoke buildTypes() simultaneously, leading to race conditions or duplicate initialization.

Expected Behavior

Thread-safe lazy initialization — buildTypes() should execute at most once regardless of concurrent access.

Actual Behavior

Data race: multiple threads can trigger buildTypes() concurrently.

Suggested Fix

Use one of:

• synchronized block on the method or a private lock object
• Double-checked locking with a volatile field
• Lazy holder idiom (static inner class)