automatically ignore known forwarded addresses, fixes #64

vendor/go.mau.fi/util/exerrors/dualerror.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package exerrors
+
+import (
+	"errors"
+	"fmt"
+)
+
+type DualError struct {
+	High error
+	Low  error
+}
+
+func NewDualError(high, low error) DualError {
+	return DualError{high, low}
+}
+
+func (err DualError) Is(other error) bool {
+	return errors.Is(other, err.High) || errors.Is(other, err.Low)
+}
+
+func (err DualError) Unwrap() error {
+	return err.Low
+}
+
+func (err DualError) Error() string {
+	return fmt.Sprintf("%v: %v", err.High, err.Low)
+}