Fix consumer info if consumer was closed

Co-authored-by: Derek Collison <derek@nats.io>
Signed-off-by: Tomasz Pietrek <tomasz@nats.io>
Signed-off-by: Derek Collison <derek@nats.io>
Signed-off-by: Tomasz Pietrek <tomasz@nats.io>

server/consumer.go

@@ -2493,7 +2493,7 @@ func (o *consumer) infoWithSnap(snap bool) *ConsumerInfo {
 func (o *consumer) infoWithSnapAndReply(snap bool, reply string) *ConsumerInfo {
 	o.mu.Lock()
 	mset := o.mset
-	if mset == nil || mset.srv == nil {
+	if o.closed || mset == nil || mset.srv == nil {
 		o.mu.Unlock()
 		return nil
 	}

server/jetstream_api.go

@@ -4286,7 +4286,13 @@ func (s *Server) jsConsumerInfoRequest(sub *subscription, c *client, _ *Account,
 		s.sendAPIErrResponse(ci, acc, subject, reply, string(msg), s.jsonResponse(&resp))
 		return
 	}
-	resp.ConsumerInfo = obs.info()
+
+	if resp.ConsumerInfo = obs.info(); resp.ConsumerInfo == nil {
+		// This consumer returned nil which means it's closed. Respond with not found.
+		resp.Error = NewJSConsumerNotFoundError()
+		s.sendAPIErrResponse(ci, acc, subject, reply, string(msg), s.jsonResponse(&resp))
+		return
+	}
 	s.sendAPIResponse(ci, acc, subject, reply, string(msg), s.jsonResponse(resp))
 }