From 4b35eb0e1a276185c8c481d462dfba1469f212bd Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Thu, 10 Mar 2022 11:54:47 -0800
Subject: [PATCH] Fix RDB.AggregationCheck when run against an empty group

---
 internal/rdb/rdb.go      |  3 +++
 internal/rdb/rdb_test.go | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/internal/rdb/rdb.go b/internal/rdb/rdb.go
index d203e37..25864db 100644
--- a/internal/rdb/rdb.go
+++ b/internal/rdb/rdb.go
@@ -1009,6 +1009,9 @@ func (r *RDB) ListGroups(qname string) ([]string, error) {
 // Returns 1 if an aggregation set was created
 var aggregationCheckCmd = redis.NewScript(`
 local size = redis.call("ZCARD", KEYS[1])
+if size == 0 then
+	return 0
+end
 local maxSize = tonumber(ARGV[1])
 if size >= maxSize then
 	local msgs = redis.call("ZRANGE", KEYS[1], 0, maxSize-1)
diff --git a/internal/rdb/rdb_test.go b/internal/rdb/rdb_test.go
index 38a1fc6..8df2b84 100644
--- a/internal/rdb/rdb_test.go
+++ b/internal/rdb/rdb_test.go
@@ -3129,6 +3129,26 @@ func TestAggregationCheck(t *testing.T) {
 		wantAggregationSet []*base.TaskMessage
 		wantGroups         map[string]map[string][]base.Z
 	}{
+		{
+			desc: "with an empty group",
+			groups: map[string]map[string][]base.Z{
+				"default": {
+					"mygroup": {},
+				},
+			},
+			qname:              "default",
+			gname:              "mygroup",
+			gracePeriod:        1 * time.Minute,
+			maxDelay:           10 * time.Minute,
+			maxSize:            5,
+			shouldCreateSet:    false,
+			wantAggregationSet: nil,
+			wantGroups: map[string]map[string][]base.Z{
+				"default": {
+					"mygroup": {},
+				},
+			},
+		},
 		{
 			desc: "with a group size reaching the max size",
 			groups: map[string]map[string][]base.Z{