*: check if GetStore returns nil (tikv#4347) (tikv#4378)

* This is an automated cherry-pick of tikv#4347

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

* fix conflicts

Signed-off-by: disksing <i@disksing.com>

server/schedule/region_scatterer.go

@@ -277,6 +277,9 @@ func (r *RegionScatterer) scatterRegion(region *core.RegionInfo, group string) *
 	// Group peers by the engine of their stores
 	for _, peer := range region.GetPeers() {
 		store := r.cluster.GetStore(peer.GetStoreId())
+		if store == nil {
+			return nil
+		}
 		if ordinaryFilter.Target(r.cluster, store) {
 			ordinaryPeers[peer.GetId()] = peer
 		} else {
@@ -415,6 +418,9 @@ func (r *RegionScatterer) selectAvailableLeaderStores(group string, peers map[ui
 	leaderCandidateStores := make([]uint64, 0)
 	for storeID := range peers {
 		store := r.cluster.GetStore(storeID)
+		if store == nil {
+			return 0
+		}
 		engine := store.GetLabelValue(filter.EngineKey)
 		if len(engine) < 1 {
 			leaderCandidateStores = append(leaderCandidateStores, storeID)
@@ -439,6 +445,9 @@ func (r *RegionScatterer) Put(peers map[uint64]*metapb.Peer, leaderStoreID uint6
 	for _, peer := range peers {
 		storeID := peer.GetStoreId()
 		store := r.cluster.GetStore(storeID)
+		if store == nil {
+			continue
+		}
 		if ordinaryFilter.Target(r.cluster, store) {
 			r.ordinaryEngine.selectedPeer.Put(storeID, group)
 			scatterDistributionCounter.WithLabelValues(

server/schedulers/shuffle_region.go

@@ -159,11 +159,15 @@ func (s *shuffleRegionScheduler) scheduleRemovePeer(cluster opt.Cluster) (*core.
 }
 
 func (s *shuffleRegionScheduler) scheduleAddPeer(cluster opt.Cluster, region *core.RegionInfo, oldPeer *metapb.Peer) *metapb.Peer {
+	store := cluster.GetStore(oldPeer.GetStoreId())
+	if store == nil {
+		return nil
+	}
 	var scoreGuard filter.Filter
 	if cluster.IsPlacementRulesEnabled() {
 		scoreGuard = filter.NewRuleFitFilter(s.GetName(), cluster, region, oldPeer.GetStoreId())
 	} else {
-		scoreGuard = filter.NewDistinctScoreFilter(s.GetName(), cluster.GetLocationLabels(), cluster.GetRegionStores(region), cluster.GetStore(oldPeer.GetStoreId()))
+		scoreGuard = filter.NewDistinctScoreFilter(s.GetName(), cluster.GetLocationLabels(), cluster.GetRegionStores(region), store)
 	}
 	excludedFilter := filter.NewExcludedFilter(s.GetName(), nil, region.GetStoreIds())
 

server/statistics/store.go

@@ -285,7 +285,7 @@ func (s *StoresStats) GetStoresKeysReadStat() map[uint64]float64 {
 
 func (s *StoresStats) storeIsUnhealthy(cluster core.StoreSetInformer, storeID uint64) bool {
 	store := cluster.GetStore(storeID)
-	return store.IsTombstone() || store.IsUnhealth()
+	return store == nil || store.IsTombstone() || store.IsUnhealth()
 }
 
 // FilterUnhealthyStore filter unhealthy store