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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package errors implements functions to manipulate errors.
//
// The New function creates errors whose only content is a text message.
//
// The Unwrap, Is and As functions work on errors that may wrap other errors.
// An error wraps another error if its type has the method
//
// Unwrap() error
//
// If e.Unwrap() returns a non-nil error w, then we say that e wraps w.
//
// Unwrap unpacks wrapped errors. If its argument's type has an
// Unwrap method, it calls the method once. Otherwise, it returns nil.
//
// A simple way to create wrapped errors is to call fmt.Errorf and apply the %w verb
// to the error argument:
//
// errors.Unwrap(fmt.Errorf("... %w ...", ..., err, ...))
//
// returns err.
//
// Is unwraps its first argument sequentially looking for an error that matches the
// second. It reports whether it finds a match. It should be used in preference to
// simple equality checks:
//
// if errors.Is(err, fs.ErrExist)
//
// is preferable to
//
// if err == fs.ErrExist
//
// because the former will succeed if err wraps fs.ErrExist.
//
// As unwraps its first argument sequentially looking for an error that can be
// assigned to its second argument, which must be a pointer. If it succeeds, it
// performs the assignment and returns true. Otherwise, it returns false. The form
//
// var perr *fs.PathError
// if errors.As(err, &perr) {
// fmt.Println(perr.Path)
// }
//
// is preferable to
//
// if perr, ok := err.(*fs.PathError); ok {
// fmt.Println(perr.Path)
// }
//
// because the former will succeed if err wraps an *fs.PathError.
package errors
// New returns an error that formats as the given text.
// Each call to New returns a distinct error value even if the text is identical.
func New(text string) error {
return &errorString{text}
}
// errorString is a trivial implementation of error.
type errorString struct {
s string
}
func (e *errorString) Error() string {
return e.s
}
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