From 103971bd9ad8b2870b51f602a8d2dfe31f25fba7 Mon Sep 17 00:00:00 2001
From: Daniel Liu <liudaniel@qq.com>
Date: Sat, 13 Jul 2024 12:02:18 +0800
Subject: [PATCH] all: check nil statedb

---
 core/blockchain.go     |  2 ++
 eth/api_backend.go     | 20 +++++++++++++++-----
 internal/ethapi/api.go |  8 ++++++++
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/core/blockchain.go b/core/blockchain.go
index 927e4628df1a..69f21fc14050 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2578,6 +2578,8 @@ func (bc *BlockChain) UpdateM1() error {
 		if err != nil {
 			return err
 		}
+	} else if stateDB == nil {
+		return errors.New("nil stateDB in UpdateM1")
 	} else {
 		candidates = state.GetCandidates(stateDB)
 	}
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 161ee5ddfb4f..1a9ebc417091 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -20,7 +20,6 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"fmt"
 	"math/big"
 	"os"
 	"path/filepath"
@@ -443,7 +442,11 @@ func (b *EthApiBackend) GetVotersRewards(masternodeAddr common.Address) map[comm
 
 	state, err := chain.StateAt(lastCheckpointBlock.Root())
 	if err != nil {
-		fmt.Println("ERROR Trying to getting state at", lastCheckpointNumber, " Error ", err)
+		log.Error("fail to get state in GetVotersRewards", "lastCheckpointNumber", lastCheckpointNumber, "err", err)
+		return nil
+	}
+	if state == nil {
+		log.Error("fail to get state in GetVotersRewards", "lastCheckpointNumber", lastCheckpointNumber)
 		return nil
 	}
 
@@ -503,7 +506,11 @@ func (b *EthApiBackend) GetVotersCap(checkpoint *big.Int, masterAddr common.Addr
 	state, err := chain.StateAt(checkpointBlock.Root())
 
 	if err != nil {
-		fmt.Println("ERROR Trying to getting state at", checkpoint, " Error ", err)
+		log.Error("fail to get state in GetVotersCap", "checkpoint", checkpoint, "err", err)
+		return nil
+	}
+	if state != nil {
+		log.Error("fail to get state in GetVotersCap", "checkpoint", checkpoint)
 		return nil
 	}
 
@@ -533,9 +540,12 @@ func (b *EthApiBackend) GetEpochDuration() *big.Int {
 func (b *EthApiBackend) GetMasternodesCap(checkpoint uint64) map[common.Address]*big.Int {
 	checkpointBlock := b.eth.blockchain.GetBlockByNumber(checkpoint)
 	state, err := b.eth.blockchain.StateAt(checkpointBlock.Root())
-
 	if err != nil {
-		fmt.Println("ERROR Trying to getting state at", checkpoint, " Error ", err)
+		log.Error("fail to get state in GetMasternodesCap", "checkpoint", checkpoint, "err", err)
+		return nil
+	}
+	if state == nil {
+		log.Error("fail to get state in GetMasternodesCap", "checkpoint", checkpoint)
 		return nil
 	}
 
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 27e217e912bc..6a0b3d171093 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -897,6 +897,10 @@ func (s *PublicBlockChainAPI) GetCandidateStatus(ctx context.Context, coinbaseAd
 			result[fieldSuccess] = false
 			return result, err
 		}
+		if statedb == nil {
+			result[fieldSuccess] = false
+			return result, errors.New("nil statedb in GetCandidateStatus")
+		}
 		candidatesAddresses := state.GetCandidates(statedb)
 		candidates = make([]utils.Masternode, 0, len(candidatesAddresses))
 		for _, address := range candidatesAddresses {
@@ -1052,6 +1056,10 @@ func (s *PublicBlockChainAPI) GetCandidates(ctx context.Context, epoch rpc.Epoch
 			result[fieldSuccess] = false
 			return result, err
 		}
+		if statedb == nil {
+			result[fieldSuccess] = false
+			return result, errors.New("nil statedb in GetCandidates")
+		}
 		candidatesAddresses := state.GetCandidates(statedb)
 		candidates = make([]utils.Masternode, 0, len(candidatesAddresses))
 		for _, address := range candidatesAddresses {