golang

A validation that only rejects self-parenting looks sufficient until a re-parent to your own descendant quietly forms a cycle in the category tree.

TL;DR: Moving A under B seemed fine but created a loop because B was already A's child. The old validation only blocked self-parenting, so the fix now walks up ancestors until it hits a root, a missing parent, or the original category. It uses the standard wrapped-error check and limits the walk to ten levels to handle legacy cycles safely.

Shipping nested categories with zero tests worked until the QA checklist asked for proof: the boot env is a contract, and constraint edges need a real MySQL.

TL;DR: Nested categories were live with no test coverage, and even the health check was broken since it missed required env vars. I patched the env setup and added three MySQL-backed integration tests for tricky deletes that mocks would hide. They run with the integration tag and -p 1 to avoid collisions on the shared test database.