backfill: delete messages for rooms the user is not in

If the chat turns out to be not bridgable due to the user not being in
the room, delete the messages, and stop trying to backfill it.

database/backfillqueue.go

@@ -106,6 +106,16 @@ func (bq *BackfillQuery) DeleteAll(userID id.UserID) error {
 	return err
 }
 
+func (bq *BackfillQuery) DeleteAllForPortal(userID id.UserID, portalKey PortalKey) error {
+	_, err := bq.db.Exec(`
+		DELETE FROM backfill_queue
+		WHERE user_mxid=$1
+			AND portal_jid=$2
+			AND portal_receiver=$3
+	`, userID, portalKey.JID, portalKey.Receiver)
+	return err
+}
+
 type Backfill struct {
 	db  *Database
 	log log.Logger

database/historysync.go

@@ -314,3 +314,13 @@ func (hsq *HistorySyncQuery) DeleteAllMessages(userID id.UserID) error {
 	_, err := hsq.db.Exec("DELETE FROM history_sync_message WHERE user_mxid=$1", userID)
 	return err
 }
+
+func (hsq *HistorySyncQuery) DeleteAllMessagesForPortal(userID id.UserID, portalKey PortalKey) error {
+	_, err := hsq.db.Exec(`
+		DELETE FROM history_sync_message
+		WHERE user_mxid=$1
+			AND portal_jid=$2
+			AND portal_receiver=$3
+	`, userID, portalKey.JID, portalKey.Receiver)
+	return err
+}

portal.go

@@ -1226,6 +1226,8 @@ func (portal *Portal) CreateMatrixRoom(user *User, groupInfo *types.GroupInfo, i
 			// before creating the matrix room
 			if errors.Is(err, whatsmeow.ErrNotInGroup) {
 				user.log.Debugfln("Skipping creating matrix room for %s because the user is not a participant", portal.Key.JID)
+				user.bridge.DB.BackfillQuery.DeleteAllForPortal(user.MXID, portal.Key)
+				user.bridge.DB.HistorySyncQuery.DeleteAllMessagesForPortal(user.MXID, portal.Key)
 				return err
 			} else if err != nil {
 				portal.log.Warnfln("Failed to get group info through %s: %v", user.JID, err)