From 4aec90fe2a90438af156928e9438bb91b332a5e1 Mon Sep 17 00:00:00 2001
From: Daniil Lashin <danil-lashin@yandex.ru>
Date: Tue, 30 Apr 2019 20:50:43 +0300
Subject: [PATCH] Fix empty frozen funds case

---
 CHANGELOG.md          |  6 ++++++
 core/state/statedb.go | 39 +++++++++++++++++++++------------------
 version/version.go    |  4 ++--
 3 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ca0ecdbe..177acf274 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.20.4
+
+BUG FIXES
+
+- [core] Fix empty frozen funds case
+
 ## 0.20.3
 
 BUG FIXES
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 6511a4be3..286fb2e4e 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -1677,30 +1677,33 @@ func (s *StateDB) deleteCoin(symbol types.CoinSymbol) {
 	// remove coin from frozen funds
 	for _, height := range frozenFundsHeights {
 		frozenFunds := s.GetStateFrozenFunds(height)
-		var newFrozenFundsList []FrozenFund
-		for _, ff := range frozenFunds.data.List {
-			if ff.Coin == symbol {
-				ret := formula.CalculateSaleReturn(coinToDelete.Volume(), coinToDelete.ReserveBalance(), 100, ff.Value)
+		if frozenFunds != nil {
+			var newFrozenFundsList []FrozenFund
 
-				coinToDelete.SubReserve(ret)
-				coinToDelete.SubVolume(ff.Value)
+			for _, ff := range frozenFunds.data.List {
+				if ff.Coin == symbol {
+					ret := formula.CalculateSaleReturn(coinToDelete.Volume(), coinToDelete.ReserveBalance(), 100, ff.Value)
 
-				newFrozenFundsList = append(newFrozenFundsList, FrozenFund{
-					Address:      ff.Address,
-					CandidateKey: ff.CandidateKey,
-					Coin:         types.GetBaseCoin(),
-					Value:        ret,
-				})
+					coinToDelete.SubReserve(ret)
+					coinToDelete.SubVolume(ff.Value)
 
-				continue
+					newFrozenFundsList = append(newFrozenFundsList, FrozenFund{
+						Address:      ff.Address,
+						CandidateKey: ff.CandidateKey,
+						Coin:         types.GetBaseCoin(),
+						Value:        ret,
+					})
+
+					continue
+				}
+
+				newFrozenFundsList = append(newFrozenFundsList, ff)
 			}
 
-			newFrozenFundsList = append(newFrozenFundsList, ff)
+			frozenFunds.data.List = newFrozenFundsList
+			s.setStateFrozenFunds(frozenFunds)
+			s.MarkStateFrozenFundsDirty(frozenFunds.blockHeight)
 		}
-
-		frozenFunds.data.List = newFrozenFundsList
-		s.setStateFrozenFunds(frozenFunds)
-		s.MarkStateFrozenFundsDirty(frozenFunds.blockHeight)
 	}
 
 	// remove coin from stakes
diff --git a/version/version.go b/version/version.go
index accc57bfa..b155cc2c2 100755
--- a/version/version.go
+++ b/version/version.go
@@ -4,14 +4,14 @@ package version
 const (
 	Maj = "0"
 	Min = "20"
-	Fix = "3"
+	Fix = "4"
 
 	AppVer = 4
 )
 
 var (
 	// Must be a string because scripts like dist.sh read this file.
-	Version = "0.20.3"
+	Version = "0.20.4"
 
 	// GitCommit is the current HEAD set using ldflags.
 	GitCommit string