Allow for errors.As() to see the underlying AMQP error (#329)

You can now do errors.As() and grab the amqp.Error{} out of Link/Session/ConnErrors.

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Release History
 
+## 1.1.0 (2024-08-20)
+
+### Features Added
+
+* ConnError, SessionError and LinkError now work with errors.As(), making it easier to write generalized error handling code that wants to deal with *amqp.Error's.
+
 ## 1.0.5 (2024-03-04)
 
 ### Bugs Fixed

errors.go

@@ -65,6 +65,15 @@ func (e *LinkError) Error() string {
 	return e.inner.Error()
 }
 
+// Unwrap returns the RemoteErr, if any.
+func (e *LinkError) Unwrap() error {
+	if e.RemoteErr == nil {
+		return nil
+	}
+
+	return e.RemoteErr
+}
+
 // ConnError is returned by methods on Conn and propagated to Session and Senders/Receivers
 // when the connection has been closed.
 type ConnError struct {
@@ -84,6 +93,15 @@ func (e *ConnError) Error() string {
 	return e.inner.Error()
 }
 
+// Unwrap returns the RemoteErr, if any.
+func (e *ConnError) Unwrap() error {
+	if e.RemoteErr == nil {
+		return nil
+	}
+
+	return e.RemoteErr
+}
+
 // SessionError is returned by methods on Session and propagated to Senders/Receivers
 // when the session has been closed.
 type SessionError struct {
@@ -102,3 +120,12 @@ func (e *SessionError) Error() string {
 	}
 	return e.inner.Error()
 }
+
+// Unwrap returns the RemoteErr, if any.
+func (e *SessionError) Unwrap() error {
+	if e.RemoteErr == nil {
+		return nil
+	}
+
+	return e.RemoteErr
+}

errors_test.go

@@ -0,0 +1,44 @@
+package amqp_test
+
+import (
+	"errors"
+	"testing"
+
+	amqp "github.com/Azure/go-amqp"
+	"github.com/stretchr/testify/require"
+)
+
+func TestErrorUnwrap(t *testing.T) {
+	// In the majority of common use cases, the LinkError, ConnError and SessionError will contain an amqp.Error.
+	// It's simpler, for callers, if they can simply check errors.As(&amqp.Error) so they can write general error
+	// handling, rather than having to check the envelope type each time.
+	t.Run("LinkError", func(t *testing.T) {
+		var amqpErr *amqp.Error
+
+		le := &amqp.LinkError{}
+		require.False(t, errors.As(le, &amqpErr))
+
+		le.RemoteErr = &amqp.Error{Condition: amqp.ErrCondConnectionForced}
+		require.ErrorAs(t, le, &amqpErr)
+	})
+
+	t.Run("ConnError", func(t *testing.T) {
+		var amqpErr *amqp.Error
+
+		ce := &amqp.ConnError{}
+		require.False(t, errors.As(ce, &amqpErr))
+
+		ce.RemoteErr = &amqp.Error{Condition: amqp.ErrCondConnectionForced}
+		require.ErrorAs(t, ce, &amqpErr)
+	})
+
+	t.Run("SessionError", func(t *testing.T) {
+		var amqpErr *amqp.Error
+
+		se := &amqp.ConnError{}
+		require.False(t, errors.As(se, &amqpErr))
+
+		se.RemoteErr = &amqp.Error{Condition: amqp.ErrCondConnectionForced}
+		require.ErrorAs(t, se, &amqpErr)
+	})
+}