When returning an error from a function, include contextual information. Use `fmt.Errorf` with `%w` (or similar error wrapping) to add a message while preserving the original error.
Providing context in errors (such as what operation failed) makes debugging easier. Wrapping errors with `%w` retains the original error for inspection (using errors.Is/As), so the root cause isn't lost. Without context, you might get a generic error with no clue of its origin.
Side-by-side examples engineers can pattern-match during review.
if err != nil {
return errors.New("operation failed") // loses original error context
}if err != nil {
return fmt.Errorf("operation failed: %w", err) // wraps original error
}if err != nil {
return errors.New("operation failed") // loses original error context
}if err != nil {
return fmt.Errorf("operation failed: %w", err) // wraps original error
}From the same buckets as this rule.
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.