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mirror of https://github.com/rclone/rclone synced 2024-11-23 00:06:55 +01:00
rclone/backend/union/errors.go
Nick Craig-Wood 31773ecfbf union: allow errors to be unwrapped for inspection
Before this change the Errors type in the union backend produced
errors which could not be Unwrapped to test their type.

This adds the (go1.20) Unwrap method to the Errors type which allows
errors.Is to work on these errors.

It also adds unit tests for the Errors type and fixes a couple of
minor bugs thrown up in the process.

See: https://forum.rclone.org/t/failed-to-set-modification-time-1-error-pcloud-cant-set-modified-time/38596
2023-06-10 14:39:41 +01:00

77 lines
1.4 KiB
Go

package union
import (
"bytes"
"fmt"
)
// The Errors type wraps a slice of errors
type Errors []error
// Map returns a copy of the error slice with all its errors modified
// according to the mapping function. If mapping returns nil,
// the error is dropped from the error slice with no replacement.
func (e Errors) Map(mapping func(error) error) Errors {
s := make([]error, len(e))
i := 0
for _, err := range e {
nerr := mapping(err)
if nerr == nil {
continue
}
s[i] = nerr
i++
}
return Errors(s[:i])
}
// FilterNil returns the Errors without nil
func (e Errors) FilterNil() Errors {
ne := e.Map(func(err error) error {
return err
})
return ne
}
// Err returns an error interface that filtered nil,
// or nil if no non-nil Error is presented.
func (e Errors) Err() error {
ne := e.FilterNil()
if len(ne) == 0 {
return nil
}
return ne
}
// Error returns a concatenated string of the contained errors
func (e Errors) Error() string {
var buf bytes.Buffer
if len(e) == 0 {
buf.WriteString("no error")
} else if len(e) == 1 {
buf.WriteString("1 error: ")
} else {
fmt.Fprintf(&buf, "%d errors: ", len(e))
}
for i, err := range e {
if i != 0 {
buf.WriteString("; ")
}
if err != nil {
buf.WriteString(err.Error())
} else {
buf.WriteString("nil error")
}
}
return buf.String()
}
// Unwrap returns the wrapped errors
func (e Errors) Unwrap() []error {
return e
}