Replace request ID when same request is restarted (#1453)

db/history.go

@@ -166,6 +166,17 @@ func (req HistoryRequest) Save() error {
 	return req.requestDB.Put(req.ID.Bytes(), val)
 }
 
+// Replace saves request with new ID and all data attached to the old one.
+func (req HistoryRequest) Replace(id common.Hash) error {
+	if (req.ID != common.Hash{}) {
+		if err := req.Delete(); err != nil {
+			return err
+		}
+	}
+	req.ID = id
+	return req.Save()
+}
+
 // Delete HistoryRequest from store and update every topic.
 func (req HistoryRequest) Delete() error {
 	return req.requestDB.Delete(req.ID.Bytes())

services/shhext/api.go

@@ -547,8 +547,7 @@ func (api *PublicAPI) requestMessagesUsingPayload(request db.HistoryRequest, pee
 	}
 	hash = envelope.Hash()
 
-	request.ID = hash
+	err = request.Replace(hash)
-	err = request.Save()
 	if err != nil {
 		return hash, err
 	}
@@ -561,10 +560,6 @@ func (api *PublicAPI) requestMessagesUsingPayload(request db.HistoryRequest, pee
 	}
 
 	if err := shh.RequestHistoricMessagesWithTimeout(mailServerNode.ID().Bytes(), envelope, timeout); err != nil {
-		err = request.Delete()
-		if err != nil {
-			return hash, err
-		}
 		if !force {
 			api.service.requestsRegistry.Unregister(hash)
 		}

services/shhext/service_test.go

@@ -887,6 +887,24 @@ func (s *RequestWithTrackingHistorySuite) TestSingleRequest() {
 	s.waitMessagesDelivered(filterid, hexes...)
 }
 
+func (s *RequestWithTrackingHistorySuite) TestPreviousRequestReplaced() {
+	topic1 := whisper.TopicType{1, 1, 1, 1}
+	topic2 := whisper.TopicType{255, 255, 255, 255}
+
+	requests := s.initiateHistoryRequest(
+		TopicRequest{Topic: topic1, Duration: time.Hour},
+		TopicRequest{Topic: topic2, Duration: time.Hour},
+	)
+	s.Require().Len(requests, 1)
+	s.localService.requestsRegistry.Clear()
+	replaced := s.initiateHistoryRequest(
+		TopicRequest{Topic: topic1, Duration: time.Hour},
+		TopicRequest{Topic: topic2, Duration: time.Hour},
+	)
+	s.Require().Len(replaced, 1)
+	s.Require().NotEqual(requests[0], replaced[0])
+}
+
 func waitForArchival(events chan whisper.EnvelopeEvent, duration time.Duration, hashes ...hexutil.Bytes) error {
 	waiting := map[common.Hash]struct{}{}
 	for _, hash := range hashes {