fix de-duplication bug and add test for it

nomad/csi_batch.go

@@ -38,6 +38,7 @@ func (c *csiBatchRelease) add(vol, namespace string) {
 	if seen {
 		return
 	}
+	c.seen[id] = struct{}{}
 
 	req := structs.CSIVolumeClaimRequest{
 		VolumeID: vol,

nomad/csi_batch_test.go

@@ -0,0 +1,34 @@
+package nomad
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCSI_Batcher(t *testing.T) {
+	t.Parallel()
+	srv, shutdown := TestServer(t, func(c *Config) {
+		c.NumSchedulers = 0 // Prevent automatic dequeue
+	})
+	defer shutdown()
+
+	batcher := newCSIBatchRelease(srv, nil, 5)
+
+	batcher.add("vol0", "global")
+	batcher.add("vol", "0global")
+	batcher.add("vol1", "global")
+	batcher.add("vol1", "global")
+	batcher.add("vol2", "global")
+	batcher.add("vol2", "other")
+	batcher.add("vol3", "global")
+	batcher.add("vol4", "global")
+	batcher.add("vol5", "global")
+	batcher.add("vol6", "global")
+
+	require.Len(t, batcher.batches, 2)
+	require.Len(t, batcher.batches[0].Claims, 5, "first batch")
+	require.Equal(t, batcher.batches[0].Claims[4].VolumeID, "vol2")
+	require.Equal(t, batcher.batches[0].Claims[4].Namespace, "other")
+	require.Len(t, batcher.batches[1].Claims, 4, "second batch")
+}