lib/errors: add support for unwrapping go1.20 multi errors
This commit is contained in:
Nick Craig-Wood
parent
ca9182d6ae
commit
844e8fb8bd
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@ -17,8 +17,10 @@ type WalkFunc func(error) bool
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// The next error in the chain is determined by the following rules:
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//
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// the return value of this method is used.
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// - If the current error has a `Unwrap() error` method (golang.org/x/xerrors),
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// - If the current error has a `Unwrap() error` method
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// the return value of this method is used.
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// - If the current error has a `Unwrap() []error` method
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// the return values of this method is used.
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// - Common errors in the Go runtime that contain an Err field will use this value.
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func Walk(err error, f WalkFunc) {
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for prev := err; err != nil; prev = err {
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@ -27,6 +29,11 @@ func Walk(err error, f WalkFunc) {
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}
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switch e := err.(type) {
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case multiWrapper:
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for _, err = range e.Unwrap() {
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Walk(err, f)
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}
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return
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case causer:
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err = e.Cause()
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case wrapper:
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@ -62,3 +69,6 @@ type causer interface {
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type wrapper interface {
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Unwrap() error
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}
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type multiWrapper interface {
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Unwrap() []error
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}
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@ -1,4 +1,4 @@
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package errors_test
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package errors
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import (
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"errors"
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@ -6,86 +6,244 @@ import (
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"testing"
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"github.com/stretchr/testify/assert"
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liberrors "github.com/rclone/rclone/lib/errors"
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)
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func TestWalk(t *testing.T) {
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origin := errors.New("origin")
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var (
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e1 = errors.New("e1")
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e2 = errors.New("e2")
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e3 = errors.New("e3")
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)
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for _, test := range []struct {
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err error
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calls int
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last error
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err error
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want []error
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}{
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{causerError{nil}, 1, causerError{nil}},
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{wrapperError{nil}, 1, wrapperError{nil}},
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{reflectError{nil}, 1, reflectError{nil}},
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{causerError{origin}, 2, origin},
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{wrapperError{origin}, 2, origin},
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{reflectError{origin}, 2, origin},
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{causerError{reflectError{origin}}, 3, origin},
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{wrapperError{causerError{origin}}, 3, origin},
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{reflectError{wrapperError{origin}}, 3, origin},
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{causerError{reflectError{causerError{origin}}}, 4, origin},
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{wrapperError{causerError{wrapperError{origin}}}, 4, origin},
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{reflectError{wrapperError{reflectError{origin}}}, 4, origin},
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{stopError{nil}, 1, stopError{nil}},
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{stopError{causerError{nil}}, 1, stopError{causerError{nil}}},
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{stopError{wrapperError{nil}}, 1, stopError{wrapperError{nil}}},
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{stopError{reflectError{nil}}, 1, stopError{reflectError{nil}}},
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{causerError{stopError{origin}}, 2, stopError{origin}},
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{wrapperError{stopError{origin}}, 2, stopError{origin}},
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{reflectError{stopError{origin}}, 2, stopError{origin}},
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{causerError{reflectError{stopError{nil}}}, 3, stopError{nil}},
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{wrapperError{causerError{stopError{nil}}}, 3, stopError{nil}},
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{reflectError{wrapperError{stopError{nil}}}, 3, stopError{nil}},
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{
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causerError{nil}, []error{
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causerError{nil},
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},
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}, {
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wrapperError{nil}, []error{
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wrapperError{nil},
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},
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}, {
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reflectError{nil}, []error{
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reflectError{nil},
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},
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}, {
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causerError{e1}, []error{
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causerError{e1}, e1,
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},
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}, {
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wrapperError{e1}, []error{
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wrapperError{e1}, e1,
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},
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}, {
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reflectError{e1}, []error{
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reflectError{e1}, e1,
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},
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}, {
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causerError{reflectError{e1}}, []error{
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causerError{reflectError{e1}},
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reflectError{e1},
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e1,
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},
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}, {
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wrapperError{causerError{e1}}, []error{
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wrapperError{causerError{e1}},
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causerError{e1},
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e1,
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},
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}, {
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reflectError{wrapperError{e1}}, []error{
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reflectError{wrapperError{e1}},
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wrapperError{e1},
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e1,
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},
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}, {
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causerError{reflectError{causerError{e1}}}, []error{
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causerError{reflectError{causerError{e1}}},
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reflectError{causerError{e1}},
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causerError{e1},
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e1,
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},
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}, {
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wrapperError{causerError{wrapperError{e1}}}, []error{
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wrapperError{causerError{wrapperError{e1}}},
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causerError{wrapperError{e1}},
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wrapperError{e1},
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e1,
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},
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}, {
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reflectError{wrapperError{reflectError{e1}}}, []error{
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reflectError{wrapperError{reflectError{e1}}},
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wrapperError{reflectError{e1}},
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reflectError{e1},
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e1,
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},
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}, {
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stopError{nil}, []error{
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stopError{nil},
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},
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}, {
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stopError{causerError{nil}}, []error{
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stopError{causerError{nil}},
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},
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}, {
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stopError{wrapperError{nil}}, []error{
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stopError{wrapperError{nil}},
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},
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}, {
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stopError{reflectError{nil}}, []error{
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stopError{reflectError{nil}},
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},
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}, {
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causerError{stopError{e1}}, []error{
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causerError{stopError{e1}},
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stopError{e1},
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},
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}, {
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wrapperError{stopError{e1}}, []error{
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wrapperError{stopError{e1}},
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stopError{e1},
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},
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}, {
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reflectError{stopError{e1}}, []error{
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reflectError{stopError{e1}},
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stopError{e1},
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},
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}, {
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causerError{reflectError{stopError{nil}}}, []error{
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causerError{reflectError{stopError{nil}}},
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reflectError{stopError{nil}},
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stopError{nil},
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},
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}, {
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wrapperError{causerError{stopError{nil}}}, []error{
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wrapperError{causerError{stopError{nil}}},
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causerError{stopError{nil}},
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stopError{nil},
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},
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}, {
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reflectError{wrapperError{stopError{nil}}}, []error{
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reflectError{wrapperError{stopError{nil}}},
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wrapperError{stopError{nil}},
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stopError{nil},
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},
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}, {
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multiWrapperError{[]error{e1}}, []error{
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multiWrapperError{[]error{e1}},
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e1,
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},
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}, {
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multiWrapperError{[]error{}}, []error{
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multiWrapperError{[]error{}},
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},
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}, {
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multiWrapperError{[]error{e1, e2, e3}}, []error{
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multiWrapperError{[]error{e1, e2, e3}},
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e1,
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e2,
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e3,
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},
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}, {
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multiWrapperError{[]error{reflectError{e1}, wrapperError{e2}, stopError{e3}}}, []error{
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multiWrapperError{[]error{reflectError{e1}, wrapperError{e2}, stopError{e3}}},
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reflectError{e1},
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e1,
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wrapperError{e2},
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e2,
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stopError{e3},
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},
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},
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} {
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var last error
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calls := 0
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liberrors.Walk(test.err, func(err error) bool {
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calls++
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last = err
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var got []error
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Walk(test.err, func(err error) bool {
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got = append(got, err)
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_, stop := err.(stopError)
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return stop
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})
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assert.Equal(t, test.calls, calls)
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assert.Equal(t, test.last, last)
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assert.Equal(t, test.want, got, test.err)
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}
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}
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type causerError struct {
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err error
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}
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type wrapperError struct {
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err error
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}
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type reflectError struct {
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Err error
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}
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type stopError struct {
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err error
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}
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func (e causerError) Error() string {
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return fmt.Sprintf("causerError(%s)", e.err)
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}
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func (e causerError) Cause() error {
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return e.err
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}
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var (
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_ error = causerError{nil}
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_ causer = causerError{nil}
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)
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type wrapperError struct {
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err error
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}
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func (e wrapperError) Unwrap() error {
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return e.err
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}
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func (e wrapperError) Error() string {
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return fmt.Sprintf("wrapperError(%s)", e.err)
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}
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var (
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_ error = wrapperError{nil}
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_ wrapper = wrapperError{nil}
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)
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type multiWrapperError struct {
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errs []error
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}
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func (e multiWrapperError) Unwrap() []error {
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return e.errs
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}
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func (e multiWrapperError) Error() string {
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return fmt.Sprintf("multiWrapperError(%s)", e.errs)
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}
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var (
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_ error = multiWrapperError{nil}
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_ multiWrapper = multiWrapperError{nil}
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)
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type reflectError struct {
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Err error
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}
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func (e reflectError) Error() string {
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return fmt.Sprintf("reflectError(%s)", e.Err)
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}
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var (
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_ error = reflectError{nil}
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)
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type stopError struct {
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err error
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}
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func (e stopError) Error() string {
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return fmt.Sprintf("stopError(%s)", e.err)
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}
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func (e stopError) Cause() error {
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return e.err
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}
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var (
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_ error = stopError{nil}
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_ causer = stopError{nil}
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)
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