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// Copyright 2022 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
// Join returns an error that wraps the given errors.
// Any nil error values are discarded.
// Join returns nil if every value in errs is nil.
// The error formats as the concatenation of the strings obtained
// by calling the Error method of each element of errs, with a newline
// between each string.
//
// A non-nil error returned by Join implements the Unwrap() []error method.
func Join(errs ...error) error {
n := 0
for _, err := range errs {
if err != nil {
n++
}
}
if n == 0 {
return nil
}
e := &joinError{
errs: make([]error, 0, n),
}
for _, err := range errs {
if err != nil {
e.errs = append(e.errs, err)
}
}
return e
}
type joinError struct {
errs []error
}
func (e *joinError) Error() string {
var b []byte
for i, err := range e.errs {
if i > 0 {
b = append(b, '\n')
}
b = append(b, err.Error()...)
}
return string(b)
}
func (e *joinError) Unwrap() []error {
return e.errs
}