Translate Infrastructure Errors at the Adapter, Not in Your Domain

Book: Decoupled PHP — Clean and Hexagonal Architecture for Applications That Outlive the Framework

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

You open the exception tracker on a Monday. The top error is SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry. It was thrown from inside RegisterUser, your use case. The stack trace climbs through PDO, through Doctrine, through the repository, and lands in a try/catch that someone wrote in the application layer to turn that SQLSTATE into a friendly message.