test low active brokers

weed/mq/pub_balancer/allocate.go

@@ -89,6 +89,7 @@ func pickBrokersExcluded(brokers []string, count int, excludedLeadBroker string,
 	return pickedBrokers
 }
 
+// EnsureAssignmentsToActiveBrokers ensures the assignments are assigned to active brokers
 func EnsureAssignmentsToActiveBrokers(activeBrokers cmap.ConcurrentMap[string, *BrokerStats], followerCount int, assignments []*mq_pb.BrokerPartitionAssignment) (hasChanges bool) {
 	candidates := make([]string, 0, activeBrokers.Count())
 	for brokerStatsItem := range activeBrokers.IterBuffered() {
@@ -123,20 +124,22 @@ func EnsureAssignmentsToActiveBrokers(activeBrokers cmap.ConcurrentMap[string, *
 			if assignment.LeaderBroker == "" {
 				assignment.LeaderBroker = pickedBrokers[i]
 				i++
+				hasChanges = true
 			}
 			j := 0
 			for ; j<len(assignment.FollowerBrokers); j++ {
 				if assignment.FollowerBrokers[j] == "" {
 					assignment.FollowerBrokers[j] = pickedBrokers[i]
 					i++
+					hasChanges = true
 				}
 			}
 			if i < len(pickedBrokers) {
 				assignment.FollowerBrokers = append(assignment.FollowerBrokers, pickedBrokers[i:]...)
+				hasChanges = true
 			}
 		}
 
-		hasChanges = hasChanges || count > 0
 	}
 
 	return

weed/mq/pub_balancer/allocate_test.go

@@ -80,6 +80,9 @@ func TestEnsureAssignmentsToActiveBrokersX(t *testing.T) {
 	activeBrokers.SetIfAbsent("localhost:4", &BrokerStats{})
 	activeBrokers.SetIfAbsent("localhost:5", &BrokerStats{})
 	activeBrokers.SetIfAbsent("localhost:6", &BrokerStats{})
+	lowActiveBrokers := cmap.New[*BrokerStats]()
+	lowActiveBrokers.SetIfAbsent("localhost:1", &BrokerStats{})
+	lowActiveBrokers.SetIfAbsent("localhost:2", &BrokerStats{})
 	tests := []struct {
 		name                   string
 		args                   args
@@ -187,6 +190,23 @@ func TestEnsureAssignmentsToActiveBrokersX(t *testing.T) {
 			},
 			hasChanges: true,
 		},
+		{
+			name: "test low active brokers",
+			args: args{
+				activeBrokers: lowActiveBrokers,
+				followerCount: 3,
+				assignments:   []*mq_pb.BrokerPartitionAssignment{
+					{
+						LeaderBroker: "localhost:1",
+						Partition: &mq_pb.Partition{},
+						FollowerBrokers: []string{
+							"localhost:2",
+						},
+					},
+				},
+			},
+			hasChanges: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {