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errors ​

Helpers extending the standard errors package.

Import ​

go
import goerrors "github.com/foomo/go/errors"

API ​

AsAny ​

go
func AsAny(err error, targets ...any) bool

Reports whether err matches any of the targets via errors.As. Each target must be a non-nil pointer to either a type that implements error, or to any interface type.

IsAny ​

go
func IsAny(err error, targets ...error) bool

Reports whether err matches any of the targets via errors.Is.

AsAnyType ​

go
func AsAnyType(err error, targets ...any) bool

Reports whether err matches the concrete type of any of the targets via errors.As. Each target must be a pointer to the error type to match (e.g. &fs.PathError{}); unlike AsAny, the caller need not declare target variables and the matched value is discarded. nil targets are skipped.

Cause ​

go
func Cause(err error) error

Unwraps err through successive types.Causer implementations and returns the root cause. Stops if an error is not a Causer, or if Cause() returns the same error instance.

Examples ​

AsAny ​

go
var (
	pathErr *fs.PathError
	numErr  *strconv.NumError
)

_, err := os.Open("/nonexistent/path")
if goerrors.AsAny(err, &numErr, &pathErr) {
	// err unwrapped into one of the targets
}

IsAny ​

go
err := fmt.Errorf("wrapped: %w", io.EOF)
if goerrors.IsAny(err, context.Canceled, io.EOF) {
	// err matches one of the sentinels
}

AsAnyType ​

go
_, err := os.Open("/nonexistent/path")
if goerrors.AsAnyType(err, &fs.PathError{}, &strconv.NumError{}) {
	// err's concrete type matched one of the targets
}

Cause ​

go
type wrapErr struct {
	msg   string
	cause error
}

func (e *wrapErr) Error() string { return e.msg }
func (e *wrapErr) Cause() error  { return e.cause }

err := &wrapErr{msg: "outer", cause: &wrapErr{msg: "inner", cause: io.EOF}}
root := goerrors.Cause(err) // io.EOF