diff options
Diffstat (limited to 'vendor/github.com/go-errors/errors/join_unwrap_backward.go')
-rw-r--r-- | vendor/github.com/go-errors/errors/join_unwrap_backward.go | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/vendor/github.com/go-errors/errors/join_unwrap_backward.go b/vendor/github.com/go-errors/errors/join_unwrap_backward.go new file mode 100644 index 000000000..50c766976 --- /dev/null +++ b/vendor/github.com/go-errors/errors/join_unwrap_backward.go @@ -0,0 +1,71 @@ +//go:build !go1.20 +// +build !go1.20 + +package errors + +// Disclaimer: functions Join and Unwrap are copied from the stdlib errors +// package v1.21.0. + +// 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 +} + +// 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. +// +// Unwrap only calls a method of the form "Unwrap() error". +// In particular Unwrap does not unwrap errors returned by [Join]. +func Unwrap(err error) error { + u, ok := err.(interface { + Unwrap() error + }) + if !ok { + return nil + } + return u.Unwrap() +} |