Merge pull request #88465 from alvaroaleman/utilerrors-implement-errors-is

Utilerrors.Aggregate: Allow using with errors.Is()

Kubernetes-commit: c812375ed605dafa3a7802fc9e21165031de9034

Godeps/Godeps.json

@@ -352,7 +352,7 @@
 		},
 		{
 			"ImportPath": "k8s.io/apimachinery",
-			"Rev": "6584f51ae935"
+			"Rev": "003f3e63f669"
 		},
 		{
 			"ImportPath": "k8s.io/gengo",

go.mod

@@ -29,7 +29,7 @@ require (
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4
 	google.golang.org/appengine v1.5.0 // indirect
 	k8s.io/api v0.0.0-20200306002249-bf5c8537bc90
-	k8s.io/apimachinery v0.0.0-20200303201514-6584f51ae935
+	k8s.io/apimachinery v0.0.0-20200306042133-003f3e63f669
 	k8s.io/klog v1.0.0
 	k8s.io/utils v0.0.0-20200229041039-0a110f9eb7ab
 	sigs.k8s.io/yaml v1.2.0
@@ -39,5 +39,5 @@ replace (
 	golang.org/x/sys => golang.org/x/sys v0.0.0-20190813064441-fde4db37ae7a // pinned to release-branch.go1.13
 	golang.org/x/tools => golang.org/x/tools v0.0.0-20190821162956-65e3620a7ae7 // pinned to release-branch.go1.13
 	k8s.io/api => k8s.io/api v0.0.0-20200306002249-bf5c8537bc90
-	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20200303201514-6584f51ae935
+	k8s.io/apimachinery => k8s.io/apimachinery v0.0.0-20200306042133-003f3e63f669
 )

go.sum

@@ -183,7 +183,7 @@ gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 k8s.io/api v0.0.0-20200306002249-bf5c8537bc90/go.mod h1:EFuendCidCp9DUXAn3QXS0nWIaAgQYL8VaCqs8KTZBA=
-k8s.io/apimachinery v0.0.0-20200303201514-6584f51ae935/go.mod h1:5X8oEhnd931nEg6/Nkumo00nT6ZsCLp2h7Xwd7Ym6P4=
+k8s.io/apimachinery v0.0.0-20200306042133-003f3e63f669/go.mod h1:5X8oEhnd931nEg6/Nkumo00nT6ZsCLp2h7Xwd7Ym6P4=
 k8s.io/gengo v0.0.0-20190128074634-0689ccc1d7d6/go.mod h1:ezvh/TsK7cY6rbqRK0oQQ8IAqLxYwwyPxAX1Pzy0ii0=
 k8s.io/klog v0.0.0-20181102134211-b9b56d5dfc92/go.mod h1:Gq+BEi5rUBO/HRz0bTSXDUcqjScdoY3a9IHpCEIOOfk=
 k8s.io/klog v0.3.0/go.mod h1:Gq+BEi5rUBO/HRz0bTSXDUcqjScdoY3a9IHpCEIOOfk=

tools/clientcmd/validation.go

@@ -86,11 +86,41 @@ func (e errConfigurationInvalid) Error() string {
 	return fmt.Sprintf("invalid configuration: %v", utilerrors.NewAggregate(e).Error())
 }
 
-// Errors implements the AggregateError interface
+// Errors implements the utilerrors.Aggregate interface
 func (e errConfigurationInvalid) Errors() []error {
 	return e
 }
 
+// Is implements the utilerrors.Aggregate interface
+func (e errConfigurationInvalid) Is(target error) bool {
+	return e.visit(func(err error) bool {
+		return errors.Is(err, target)
+	})
+}
+
+func (e errConfigurationInvalid) visit(f func(err error) bool) bool {
+	for _, err := range e {
+		switch err := err.(type) {
+		case errConfigurationInvalid:
+			if match := err.visit(f); match {
+				return match
+			}
+		case utilerrors.Aggregate:
+			for _, nestedErr := range err.Errors() {
+				if match := f(nestedErr); match {
+					return match
+				}
+			}
+		default:
+			if match := f(err); match {
+				return match
+			}
+		}
+	}
+
+	return false
+}
+
 // IsConfigurationInvalid returns true if the provided error indicates the configuration is invalid.
 func IsConfigurationInvalid(err error) bool {
 	switch err.(type) {

tools/clientcmd/validation_test.go

@@ -17,6 +17,8 @@ limitations under the License.
 package clientcmd
 
 import (
+	"errors"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"strings"
@@ -569,3 +571,100 @@ func (c configValidationTest) testAuthInfo(authInfoName string, t *testing.T) {
 		}
 	}
 }
+
+type alwaysMatchingError struct{}
+
+func (_ alwaysMatchingError) Error() string {
+	return "error"
+}
+
+func (_ alwaysMatchingError) Is(_ error) bool {
+	return true
+}
+
+type someError struct{ msg string }
+
+func (se someError) Error() string {
+	if se.msg != "" {
+		return se.msg
+	}
+	return "err"
+}
+
+func TestErrConfigurationInvalidWithErrorsIs(t *testing.T) {
+	testCases := []struct {
+		name         string
+		err          error
+		matchAgainst error
+		expectMatch  bool
+	}{
+		{
+			name:         "no match",
+			err:          errConfigurationInvalid{errors.New("my-error"), errors.New("my-other-error")},
+			matchAgainst: fmt.Errorf("no entry %s", "here"),
+		},
+		{
+			name:         "match via .Is()",
+			err:          errConfigurationInvalid{errors.New("forbidden"), alwaysMatchingError{}},
+			matchAgainst: errors.New("unauthorized"),
+			expectMatch:  true,
+		},
+		{
+			name:         "match via equality",
+			err:          errConfigurationInvalid{errors.New("err"), someError{}},
+			matchAgainst: someError{},
+			expectMatch:  true,
+		},
+		{
+			name:         "match via nested aggregate",
+			err:          errConfigurationInvalid{errors.New("closed today"), errConfigurationInvalid{errConfigurationInvalid{someError{}}}},
+			matchAgainst: someError{},
+			expectMatch:  true,
+		},
+		{
+			name:         "match via wrapped aggregate",
+			err:          fmt.Errorf("wrap: %w", errConfigurationInvalid{errors.New("err"), someError{}}),
+			matchAgainst: someError{},
+			expectMatch:  true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := errors.Is(tc.err, tc.matchAgainst)
+			if result != tc.expectMatch {
+				t.Errorf("expected match: %t, got match: %t", tc.expectMatch, result)
+			}
+		})
+	}
+}
+
+type accessTrackingError struct {
+	wasAccessed bool
+}
+
+func (accessTrackingError) Error() string {
+	return "err"
+}
+
+func (ate *accessTrackingError) Is(_ error) bool {
+	ate.wasAccessed = true
+	return true
+}
+
+var _ error = &accessTrackingError{}
+
+func TestErrConfigurationInvalidWithErrorsIsShortCircuitsOnFirstMatch(t *testing.T) {
+	errC := errConfigurationInvalid{&accessTrackingError{}, &accessTrackingError{}}
+	_ = errors.Is(errC, &accessTrackingError{})
+
+	var numAccessed int
+	for _, err := range errC {
+		if ate := err.(*accessTrackingError); ate.wasAccessed {
+			numAccessed++
+		}
+	}
+	if numAccessed != 1 {
+		t.Errorf("expected exactly one error to get accessed, got %d", numAccessed)
+	}
+}