chainederrors

Go library which supports error chains so errors.Is() works with nested errors. The Wrap method is designed to replace fmt.Errorf and improve the limitation where the original error wrapped by fmt.Errorf is hidden.

var (
    errGetUserInfo = errors.New("get user info")
    errReadDocument = errors.New("read document")
    errNotFound = errors.New("document not found")
)

// wrap errors using fmt
nestedErr := fmt.Errorf("%w : %s", errReadDocument, errNotFound)
err := fmt.Errorf("%w : %s", errGetUserInfo, nestedErr)

// original error is hidden
fmt.Printf("errors.Is(err, errNotFound) = %t \n", errors.Is(err, errNotFound)) // false

// wrap errors using chainederrors
nestedErr = chainederrors.Wrap(errReadDocument, errNotFound)
err = chainederrors.Wrap(errGetUserInfo, nestedErr)

// original error is now nested and "checkable"
fmt.Printf("errors.Is(err, errNotFound) = %t \n", errors.Is(err, errNotFound)) // true

// nested error String() format
fmt.Printf("err.Error() = %s \n", err.Error()) // get user info : read document : document not found