Fetch more data for newly joined rooms in an incremental sync (#2657)

If we've joined a new room in an incremental sync, try fetching more data.
This deflakes the complement server notices test (at least in my tests).

1 files changed, 9 insertions, 3 deletions

diff --git a/syncapi/internal/keychange.go b/syncapi/internal/keychange.go
index 23824e36..c5180e33 100644
--- a/syncapi/internal/keychange.go
+++ b/syncapi/internal/keychange.go
@@ -18,14 +18,16 @@ import (
 	"context"
 	"strings"
 
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	"github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+
 	keyapi "github.com/matrix-org/dendrite/keyserver/api"
 	keytypes "github.com/matrix-org/dendrite/keyserver/types"
 	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/types"
-	"github.com/matrix-org/gomatrixserverlib"
-	"github.com/matrix-org/util"
-	"github.com/sirupsen/logrus"
 )
 
 // DeviceOTKCounts adds one-time key counts to the /sync response
@@ -277,6 +279,10 @@ func membershipEventPresent(events []gomatrixserverlib.ClientEvent, userID strin
 		// it's enough to know that we have our member event here, don't need to check membership content
 		// as it's implied by being in the respective section of the sync response.
 		if ev.Type == gomatrixserverlib.MRoomMember && ev.StateKey != nil && *ev.StateKey == userID {
+			// ignore e.g. join -> join changes
+			if gjson.GetBytes(ev.Unsigned, "prev_content.membership").Str == gjson.GetBytes(ev.Content, "membership").Str {
+				continue
+			}
 			return true
 		}
 	}