7 Errors In Go

Go treats errors as ordinary values, which keeps failure handling explicit and close to the code that may fail. Functions usually return an error as the last result, and callers check whether it is nil before continuing. This approach favors clarity over hidden control flow, making it easy to see which operations can fail and to decide right away whether to return, retry, log, or otherwise respond.

The chapter shows how to create and use errors in several ways, starting with simple messages from errors.New and formatted context from fmt.Errorf. It then moves to sentinel errors, which are reusable named values that represent common conditions such as conflicts or missing data, and explains how errors.Is helps detect them even when errors are wrapped. It also demonstrates custom error types that carry extra information, such as a list of missing keys, and how errors.As can extract that underlying type for more detailed handling.

For reporting, the text emphasizes adding context when logging or rewrapping errors so that failures are easier to diagnose. It then discusses exceptional situations with panic and recover, using them only when a program cannot safely continue or when an unrecoverable internal state demands an immediate stop. In most cases, the guidance is to avoid panic, prefer ordinary error returns, and handle problems as early and clearly as possible.