Book: The Complete Guide to Go Programming Also by me: Thinking in Go (2-book series) — Complete Guide to Go Programming + Hexagonal Architecture in Go My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub A junior engineer joins your team. Their first PR is a clean refactor of an error path. The CI passes. Two reviewers approve. It ships on a Friday afternoon and the on-call rotation gets paged on Saturday morning because a service that has run fine for two years suddenly starts panicking under load. Twelve lines in the diff. One of them is the bug. The fix takes one keyword: return the untyped nil keyword instead of a typed pointer through an error interface. If that sentence felt obvious, this post is not for you. If it did not, sit down, because this is the bug that bites most Go shops sooner or later and it is going to bite yours next. The Comparison That Lies Run this. It is the smallest version of the bug.…