Merge pull request #108532 from cbandy/status-cause

Use errors.As to detect wrapping in StatusCause

staging/src/k8s.io/apimachinery/pkg/api/errors/errors.go

@@ -87,21 +87,21 @@ func (e *StatusError) DebugError() (string, []interface{}) {
 
 // HasStatusCause returns true if the provided error has a details cause
 // with the provided type name.
+// It supports wrapped errors and returns false when the error is nil.
 func HasStatusCause(err error, name metav1.CauseType) bool {
 	_, ok := StatusCause(err, name)
 	return ok
 }
 
 // StatusCause returns the named cause from the provided error if it exists and
-// the error is of the type APIStatus. Otherwise it returns false.
+// the error unwraps to the type APIStatus. Otherwise it returns false.
 func StatusCause(err error, name metav1.CauseType) (metav1.StatusCause, bool) {
-	apierr, ok := err.(APIStatus)
+	status, ok := err.(APIStatus)
-	if !ok || apierr == nil || apierr.Status().Details == nil {
+	if (ok || errors.As(err, &status)) && status.Status().Details != nil {
-		return metav1.StatusCause{}, false
+		for _, cause := range status.Status().Details.Causes {
-	}
+			if cause.Type == name {
-	for _, cause := range apierr.Status().Details.Causes {
+				return cause, true
-		if cause.Type == name {
+			}
-			return cause, true
 		}
 	}
 	return metav1.StatusCause{}, false
@@ -757,7 +757,8 @@ func IsRequestEntityTooLargeError(err error) bool {
 // and may be the result of another HTTP actor.
 // It supports wrapped errors and returns false when the error is nil.
 func IsUnexpectedServerError(err error) bool {
-	if status := APIStatus(nil); errors.As(err, &status) && status.Status().Details != nil {
+	status, ok := err.(APIStatus)
+	if (ok || errors.As(err, &status)) && status.Status().Details != nil {
 		for _, cause := range status.Status().Details.Causes {
 			if cause.Type == metav1.CauseTypeUnexpectedServerResponse {
 				return true
@@ -770,8 +771,8 @@ func IsUnexpectedServerError(err error) bool {
 // IsUnexpectedObjectError determines if err is due to an unexpected object from the master.
 // It supports wrapped errors and returns false when the error is nil.
 func IsUnexpectedObjectError(err error) bool {
-	uoe := &UnexpectedObjectError{}
+	uoe, ok := err.(*UnexpectedObjectError)
-	return err != nil && errors.As(err, &uoe)
+	return err != nil && (ok || errors.As(err, &uoe))
 }
 
 // SuggestsClientDelay returns true if this error suggests a client delay as well as the
@@ -780,7 +781,8 @@ func IsUnexpectedObjectError(err error) bool {
 // request delay without retry.
 // It supports wrapped errors and returns false when the error is nil.
 func SuggestsClientDelay(err error) (int, bool) {
-	if t := APIStatus(nil); errors.As(err, &t) && t.Status().Details != nil {
+	t, ok := err.(APIStatus)
+	if (ok || errors.As(err, &t)) && t.Status().Details != nil {
 		switch t.Status().Reason {
 		// this StatusReason explicitly requests the caller to delay the action
 		case metav1.StatusReasonServerTimeout:
@@ -798,14 +800,14 @@ func SuggestsClientDelay(err error) (int, bool) {
 // It supports wrapped errors and returns StatusReasonUnknown when
 // the error is nil or doesn't have a status.
 func ReasonForError(err error) metav1.StatusReason {
-	if status := APIStatus(nil); errors.As(err, &status) {
+	if status, ok := err.(APIStatus); ok || errors.As(err, &status) {
 		return status.Status().Reason
 	}
 	return metav1.StatusReasonUnknown
 }
 
 func reasonAndCodeForError(err error) (metav1.StatusReason, int32) {
-	if status := APIStatus(nil); errors.As(err, &status) {
+	if status, ok := err.(APIStatus); ok || errors.As(err, &status) {
 		return status.Status().Reason, status.Status().Code
 	}
 	return metav1.StatusReasonUnknown, 0

staging/src/k8s.io/apimachinery/pkg/api/errors/errors_test.go

@@ -625,3 +625,81 @@ func TestIsErrorTypesByReasonAndCode(t *testing.T) {
 
 	}
 }
+
+func TestStatusCauseSupportsWrappedErrors(t *testing.T) {
+	err := &StatusError{ErrStatus: metav1.Status{
+		Details: &metav1.StatusDetails{
+			Causes: []metav1.StatusCause{{Type: "SomeCause"}},
+		},
+	}}
+
+	if cause, ok := StatusCause(nil, "SomeCause"); ok {
+		t.Errorf("expected no cause for nil, got %v: %#v", ok, cause)
+	}
+	if cause, ok := StatusCause(errors.New("boom"), "SomeCause"); ok {
+		t.Errorf("expected no cause for wrong type, got %v: %#v", ok, cause)
+	}
+
+	if cause, ok := StatusCause(err, "Other"); ok {
+		t.Errorf("expected no cause for wrong name, got %v: %#v", ok, cause)
+	}
+	if cause, ok := StatusCause(err, "SomeCause"); !ok || cause != err.ErrStatus.Details.Causes[0] {
+		t.Errorf("expected cause, got %v: %#v", ok, cause)
+	}
+
+	wrapped := fmt.Errorf("once: %w", err)
+	if cause, ok := StatusCause(wrapped, "SomeCause"); !ok || cause != err.ErrStatus.Details.Causes[0] {
+		t.Errorf("expected cause when wrapped, got %v: %#v", ok, cause)
+	}
+
+	nested := fmt.Errorf("twice: %w", wrapped)
+	if cause, ok := StatusCause(nested, "SomeCause"); !ok || cause != err.ErrStatus.Details.Causes[0] {
+		t.Errorf("expected cause when nested, got %v: %#v", ok, cause)
+	}
+}
+
+func BenchmarkIsAlreadyExistsWrappedErrors(b *testing.B) {
+	err := NewAlreadyExists(schema.GroupResource{}, "")
+	wrapped := fmt.Errorf("once: %w", err)
+
+	b.Run("Nil", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsAlreadyExists(nil)
+		}
+	})
+
+	b.Run("Bare", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsAlreadyExists(err)
+		}
+	})
+
+	b.Run("Wrapped", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsAlreadyExists(wrapped)
+		}
+	})
+}
+
+func BenchmarkIsNotFoundWrappedErrors(b *testing.B) {
+	err := NewNotFound(schema.GroupResource{}, "")
+	wrapped := fmt.Errorf("once: %w", err)
+
+	b.Run("Nil", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsNotFound(nil)
+		}
+	})
+
+	b.Run("Bare", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsNotFound(err)
+		}
+	})
+
+	b.Run("Wrapped", func(b *testing.B) {
+		for i := 0; i < b.N; i++ {
+			IsNotFound(wrapped)
+		}
+	})
+}