[tracer] fix bug of nil reference

api/service/explorer/storage.go

@@ -305,7 +305,9 @@ LOOP:
 			}
 			traceResult.btc = bc.db.NewBatch()
 			traceResult.data.ToDB(func(key, value []byte) {
+				if exist, err := isTraceResultInDB(bc.db, key); !exist && err == nil {
 					_ = writeTraceResult(traceResult.btc, key, value)
+				}
 			})
 			select {
 			case bc.resultT <- traceResult:

core/blockchain.go

@@ -1453,8 +1453,10 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifyHeaders bool) (int,
 		vmConfig := bc.vmConfig
 		if bc.trace {
 			ev := TraceEvent{
-				Block:  block,
+				Tracer: &tracers.ParityBlockTracer{
-				Tracer: &tracers.ParityBlockTracer{},
+					Hash:   block.Hash(),
+					Number: block.NumberU64(),
+				},
 			}
 			vmConfig = vm.Config{
 				Debug:  true,

core/events.go

@@ -44,7 +44,6 @@ type ChainEvent struct {
 }
 
 type TraceEvent struct {
-	Block  *types.Block
 	Tracer *tracers.ParityBlockTracer
 }
 

hmy/tracers/block_tracer.go

@@ -203,6 +203,8 @@ type ParityTxTracer struct {
 	action
 }
 type ParityBlockTracer struct {
+	Hash    common.Hash
+	Number  uint64
 	cur     *ParityTxTracer
 	tracers []*ParityTxTracer
 }
@@ -401,8 +403,8 @@ func (jst *ParityBlockTracer) CaptureEnd(output []byte, gasUsed uint64, t time.D
 
 func (jst *ParityBlockTracer) GetStorage() *TraceBlockStorage {
 	blockStorage := &TraceBlockStorage{
-		Hash:         jst.cur.blockHash,
+		Hash:         jst.Hash,
-		Number:       jst.cur.blockNumber,
+		Number:       jst.Number,
 		addressIndex: make(map[common.Address]int),
 		dataIndex:    make(map[common.Hash]int),
 	}