Golang Pitfalls: Error Handling

Source material: mistakes #48-54 from 100 Go Mistakes and How to Avoid Them (teivah/100-go-mistakes).

Apply these rules when handling errors in Go.

48. Panicking (#48)

• panic stops the normal flow. Use it sparingly, only for unrecoverable conditions:
  • Signaling a programmer error (e.g., sql.Register with a nil/already-registered driver).
  • Failing to create a mandatory dependency.
• In almost all other cases, return a proper error as the last return value instead of panicking.

49. Ignoring when to wrap an error (#49)

• Since Go 1.13, fmt.Errorf("...: %w", err) wraps an error, making the source error available to the caller.
• Wrap to add context (use %w) or to mark an error as a specific type (create a custom error type).
• Wrapping creates coupling — callers can unwrap/compare the source error. If that's unwanted, transform the error instead (fmt.Errorf("...: %v", err)).