Looks like AckAll won't work on a pull subscription

setup/jetstream/helpers.go

@@ -34,14 +34,6 @@ func JetStreamConsumer(
 		}
 	}()
 
-	// If the batch size is greater than 1, we will want to acknowledge all
-	// received messages in the batch. Below we will send an acknowledgement
-	// for the most recent message in the batch and AckAll will ensure that
-	// all messages that came before it are also acknowledged implicitly.
-	if batch > 1 {
-		opts = append(opts, nats.AckAll())
-	}
-
 	name := durable + "Pull"
 	sub, err := js.PullSubscribe(subj, name, opts...)
 	if err != nil {
@@ -49,6 +41,7 @@ func JetStreamConsumer(
 		return fmt.Errorf("nats.SubscribeSync: %w", err)
 	}
 	go func() {
+	nextmsg:
 		for {
 			// If the parent context has given up then there's no point in
 			// carrying on doing anything, so stop the listener.
@@ -89,24 +82,29 @@ func JetStreamConsumer(
 			if len(msgs) < 1 {
 				continue
 			}
-			msg := msgs[len(msgs)-1] // most recent message, in case of AckAll
+			for _, msg := range msgs {
 				if err = msg.InProgress(nats.Context(ctx)); err != nil {
 					logrus.WithContext(ctx).WithField("subject", subj).Warn(fmt.Errorf("msg.InProgress: %w", err))
 					sentry.CaptureException(err)
-				continue
+					continue nextmsg
+				}
 			}
 			if f(ctx, msgs) {
+				for _, msg := range msgs {
 					if err = msg.AckSync(nats.Context(ctx)); err != nil {
 						logrus.WithContext(ctx).WithField("subject", subj).Warn(fmt.Errorf("msg.AckSync: %w", err))
 						sentry.CaptureException(err)
 					}
+				}
 			} else {
+				for _, msg := range msgs {
 					if err = msg.Nak(nats.Context(ctx)); err != nil {
 						logrus.WithContext(ctx).WithField("subject", subj).Warn(fmt.Errorf("msg.Nak: %w", err))
 						sentry.CaptureException(err)
 					}
 				}
 			}
+		}
 	}()
 	return nil
 }