[#1604] policer: Do not process the same node twice

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/services/policer/check.go

@@ -126,12 +126,11 @@ func (p *Policer) processRepNodes(ctx context.Context, requirements *placementRe
 		} else {
 			if status := checkedNodes.processStatus(nodes[i]); status.Processed() {
 				if status == nodeHoldsObject {
-					// node already contains replica, no need to replicate
-					nodes = append(nodes[:i], nodes[i+1:]...)
-					i--
 					shortage--
 				}
 
+				nodes = append(nodes[:i], nodes[i+1:]...)
+				i--
 				continue
 			}
 
@@ -155,6 +154,7 @@ func (p *Policer) processRepNodes(ctx context.Context, requirements *placementRe
 						zap.Stringer("object", addr),
 						zap.Error(err),
 					)
+					checkedNodes.set(nodes[i], nodeStatusUnknown)
 				}
 			}
 		}

pkg/services/policer/nodecache.go

@@ -8,6 +8,7 @@ const (
 	nodeNotProcessed nodeProcessStatus = iota
 	nodeDoesNotHoldObject
 	nodeHoldsObject
+	nodeStatusUnknown
 )
 
 func (st nodeProcessStatus) Processed() bool {

pkg/services/policer/policer_test.go

@@ -127,7 +127,7 @@ func TestProcessObject(t *testing.T) {
 			nodeCount:       2,
 			policy:          `REP 2 REP 2`,
 			placement:       [][]int{{0, 1}, {0, 1}},
-			wantReplicateTo: []int{1, 1}, // is this actually good?
+			wantReplicateTo: []int{1},
 		},
 		{
 			desc:            "lock object must be replicated to all nodes",