fix: returns descriptive error in case no sequencer registered on the…

… hub (dymensionxyz#305)

settlement/base.go

@@ -73,9 +73,6 @@ func (b *BaseLayerClient) Init(config []byte, pubsub *pubsub.Server, logger log.
 	b.logger.Info("Updated latest height from settlement layer", "latestHeight", endHeight)
 	b.sequencersList, err = b.fetchSequencersList()
 	if err != nil {
-		if err == ErrNoSequencerForRollapp {
-			panic(err)
-		}
 		return err
 	}
 	b.logger.Info("Updated sequencers list from settlement layer", "sequencersList", b.sequencersList)

settlement/dymension/dymension.go

@@ -256,9 +256,6 @@ func (d *HubClient) GetBatchAtIndex(rollappID string, index uint64) (*settlement
 func (d *HubClient) GetSequencers(rollappID string) ([]*types.Sequencer, error) {
 	sequencers, err := d.sequencerQueryClient.SequencersByRollapp(d.ctx, &sequencertypes.QueryGetSequencersByRollappRequest{RollappId: d.config.RollappID})
 	if err != nil {
-		return nil, err
-	}
-	if sequencers == nil {
 		return nil, settlement.ErrNoSequencerForRollapp
 	}
 	sequencersList := []*types.Sequencer{}

settlement/errors.go

@@ -6,5 +6,5 @@ var (
 	// ErrBatchNotFound is returned when a batch is not found for the rollapp.
 	ErrBatchNotFound = errors.New("batch not found")
 	// ErrNoSequencerForRollapp is returned when a sequencer is not found for the rollapp.
-	ErrNoSequencerForRollapp = errors.New("no sequencer for rollapp")
+	ErrNoSequencerForRollapp = errors.New("no sequencer registered on the hub for this rollapp")
 )

settlement/settlement_test.go

@@ -137,7 +137,11 @@ func TestGetSequencersEmptyList(t *testing.T) {
 	options := []settlement.Option{
 		settlement.WithHubClient(hubClientMock),
 	}
-	assert.Panics(t, func() { initClient(t, settlementClient, options...) })
+
+	pubsubServer := pubsub.NewServer()
+	pubsubServer.Start()
+	err := settlementClient.Init([]byte{}, pubsubServer, test.NewLogger(t), options...)
+	assert.Error(t, err, "empty sequencer list should return an error")
 
 }