| // 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 |
| } |