blob: be0d10d0c793dd8c2962300be806becfed3af273 [file] [log] [blame]
Matteo Scandoloa4285862020-12-01 18:10:10 -08001// +build go1.13
2
3package errors
4
5import (
6 stderrors "errors"
7)
8
9// Is reports whether any error in err's chain matches target.
10//
11// The chain consists of err itself followed by the sequence of errors obtained by
12// repeatedly calling Unwrap.
13//
14// An error is considered to match a target if it is equal to that target or if
15// it implements a method Is(error) bool such that Is(target) returns true.
16func Is(err, target error) bool { return stderrors.Is(err, target) }
17
18// As finds the first error in err's chain that matches target, and if so, sets
19// target to that error value and returns true.
20//
21// The chain consists of err itself followed by the sequence of errors obtained by
22// repeatedly calling Unwrap.
23//
24// An error matches target if the error's concrete value is assignable to the value
25// pointed to by target, or if the error has a method As(interface{}) bool such that
26// As(target) returns true. In the latter case, the As method is responsible for
27// setting target.
28//
29// As will panic if target is not a non-nil pointer to either a type that implements
30// error, or to any interface type. As returns false if err is nil.
31func As(err error, target interface{}) bool { return stderrors.As(err, target) }
32
33// Unwrap returns the result of calling the Unwrap method on err, if err's
34// type contains an Unwrap method returning error.
35// Otherwise, Unwrap returns nil.
36func Unwrap(err error) error {
37 return stderrors.Unwrap(err)
38}