fix: when max weight is 100000000, the replicas can be negative.

Signed-off-by: Liming Liu <andyliuliming@outlook.com>

utils/replicaset/canary.go

@@ -383,7 +383,7 @@ func CalculateReplicaCountsForTrafficRoutedCanary(rollout *v1alpha1.Rollout, wei
 // trafficWeightToReplicas returns the appropriate replicas given the full spec.replicas and a weight
 // Rounds up if not evenly divisible.
 func trafficWeightToReplicas(replicas, weight, maxWeight int32) int32 {
-	return int32(math.Ceil(float64(weight*replicas) / float64(maxWeight)))
+	return int32(math.Ceil(float64(weight) * float64(replicas) / float64(maxWeight)))
 }
 
 func max(left, right int32) int32 {

utils/replicaset/canary_test.go

@@ -960,6 +960,7 @@ func TestTrafficWeightToReplicas(t *testing.T) {
 	assert.Equal(t, int32(4), trafficWeightToReplicas(10, 33, 100))
 	assert.Equal(t, int32(10), trafficWeightToReplicas(10, 99, 100))
 	assert.Equal(t, int32(10), trafficWeightToReplicas(10, 100, 100))
+	assert.Equal(t, int32(23), trafficWeightToReplicas(23, 100000000, 100000000))
 }
 
 func TestGetOtherRSs(t *testing.T) {