compat.go

package errors

import "errors"

// Is reports whether any error in err's chain matches target.
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error is considered to match a target if it is equal to that target or if
// it implements a method Is(error) bool such that Is(target) returns true.
//
// An error type might provide an Is method so it can be treated as equivalent
// to an existing error.
//
// This function is an alias to [errors.Is] in the standard library.
func Is(err, target error) bool { return errors.Is(err, target) }

// Unwrap returns the result of calling the Unwrap method on err, if err's
// type contains an Unwrap method returning error.
// Otherwise, Unwrap returns nil.
//
// This function is an alias to [errors.Unwrap] in the standard library.
func Unwrap(err error) error { return errors.Unwrap(err) }

// As finds the first error in err's chain that matches target, and if so, sets
// target to that error value and returns true. Otherwise, it returns false.
//
// The chain consists of err itself followed by the sequence of errors obtained by
// repeatedly calling Unwrap.
//
// An error matches target if the error's concrete value is assignable to the value
// pointed to by target, or if the error has a method As(interface{}) bool such that
// As(target) returns true. In the latter case, the As method is responsible for
// setting target.
//
// An error type might provide an As method so it can be treated as if it were a
// different error type.
//
// As panics if target is not a non-nil pointer to either a type that implements
// error, or to any interface type.
//
// This function is an alias to [errors.As] in the standard library.
func As(err error, target interface{}) bool { return errors.As(err, target) }