An invalid err != nil check may cause the merged TS inconsistent

[JmPotato]

Bug Report

pd/pkg/tso/keyspace_group_manager.go

Lines 1365 to 1384 in 1c1cd99

	var mergedTS time.Time
	for _, id := range mergeList {
	ts, err := kgm.tsoSvcStorage.LoadTimestamp(endpoint.KeyspaceGroupGlobalTSPath(id))
	if err != nil {
	log.Error("failed to load the keyspace group TSO",
	zap.String("member", kgm.tsoServiceID.ServiceAddr),
	zap.Uint32("merge-target-id", mergeTargetID),
	zap.Any("merge-list", mergeList),
	zap.Uint32("merge-id", id),
	zap.Time("ts", ts),
	zap.Error(err))
	break
	}
	if ts.After(mergedTS) {
	mergedTS = ts
	}
	}
	if err != nil {
	continue
	}

Since the err in the loop is a local variable, so the check at line 1382 will always be false.