From f21fce1cfd80dff905580041444ffd59afd60e07 Mon Sep 17 00:00:00 2001
From: zjubfd <296179868@qq.com>
Date: Wed, 30 Oct 2019 16:38:51 +0800
Subject: [PATCH] [R4R] fix account may have currency with zero balance (#679)

* hardfork: fix possible zero currency balance

* add change log

* fix review suggest
---
 CHANGELOG_PENDING.md        | 1 +
 app/app.go                  | 1 +
 app/config/config.go        | 4 ++++
 common/upgrade/upgrade.go   | 1 +
 plugins/dex/order/keeper.go | 9 ++++++---
 5 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index b20233e2b..691db3459 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -2,6 +2,7 @@
 ## Develop
 
 BUG FIXES
+* [\#677](https://github.com/binance-chain/node/pull/677) [Dex] fix account may have currency with zero balance 
 
 IMPROVEMENTS
 * [\#672](https://github.com/binance-chain/node/pull/672) [DEX] Change listing rule
diff --git a/app/app.go b/app/app.go
index b95f30f4e..d76a29dfe 100644
--- a/app/app.go
+++ b/app/app.go
@@ -260,6 +260,7 @@ func SetUpgradeConfig(upgradeConfig *config.UpgradeConfig) {
 	upgrade.Mgr.AddUpgradeHeight(upgrade.FixSignBytesOverflow, upgradeConfig.FixSignBytesOverflowHeight)
 	upgrade.Mgr.AddUpgradeHeight(upgrade.LotSizeOptimization, upgradeConfig.LotSizeUpgradeHeight)
 	upgrade.Mgr.AddUpgradeHeight(upgrade.ListingRuleUpgrade, upgradeConfig.ListingRuleUpgradeHeight)
+	upgrade.Mgr.AddUpgradeHeight(upgrade.FixZeroBalance, upgradeConfig.FixZeroBalanceHeight)
 
 	// register store keys of upgrade
 	upgrade.Mgr.RegisterStoreKeys(upgrade.BEP9, common.TimeLockStoreKey.Name())
diff --git a/app/config/config.go b/app/config/config.go
index d9389f355..f081c0b5c 100644
--- a/app/config/config.go
+++ b/app/config/config.go
@@ -65,6 +65,8 @@ FixSignBytesOverflowHeight = {{ .UpgradeConfig.FixSignBytesOverflowHeight }}
 LotSizeUpgradeHeight = {{ .UpgradeConfig.LotSizeUpgradeHeight }}
 # Block height of changing listing rule upgrade
 ListingRuleUpgradeHeight = {{ .UpgradeConfig.ListingRuleUpgradeHeight }}
+# Block height of FixZeroBalanceHeight upgrade
+FixZeroBalanceHeight = {{ .UpgradeConfig.FixZeroBalanceHeight }}
 
 [query]
 # ABCI query interface black list, suggested value: ["custom/gov/proposals", "custom/timelock/timelocks", "custom/atomicSwap/swapcreator", "custom/atomicSwap/swaprecipient"]
@@ -353,6 +355,7 @@ type UpgradeConfig struct {
 	FixSignBytesOverflowHeight int64 `mapstructure:"FixSignBytesOverflowHeight"`
 	LotSizeUpgradeHeight       int64 `mapstructure:"LotSizeUpgradeHeight"`
 	ListingRuleUpgradeHeight   int64 `mapstructure:"ListingRuleUpgradeHeight"`
+	FixZeroBalanceHeight       int64 `mapstructure:"FixZeroBalanceHeight"`
 }
 
 func defaultUpgradeConfig() *UpgradeConfig {
@@ -367,6 +370,7 @@ func defaultUpgradeConfig() *UpgradeConfig {
 		FixSignBytesOverflowHeight: math.MaxInt64,
 		LotSizeUpgradeHeight:       math.MaxInt64,
 		ListingRuleUpgradeHeight:   math.MaxInt64,
+		FixZeroBalanceHeight:       math.MaxInt64,
 	}
 }
 
diff --git a/common/upgrade/upgrade.go b/common/upgrade/upgrade.go
index 059219b8c..c1ecba7de 100644
--- a/common/upgrade/upgrade.go
+++ b/common/upgrade/upgrade.go
@@ -21,6 +21,7 @@ const (
 	FixSignBytesOverflow = sdk.FixSignBytesOverflow
 	LotSizeOptimization  = "LotSizeOptimization"
 	ListingRuleUpgrade   = "ListingRuleUpgrade" // Remove restriction that only the owner of base asset can list trading pair
+	FixZeroBalance       = "FixZeroBalance"
 )
 
 func UpgradeBEP10(before func(), after func()) {
diff --git a/plugins/dex/order/keeper.go b/plugins/dex/order/keeper.go
index 86a6e318a..31cb17e62 100644
--- a/plugins/dex/order/keeper.go
+++ b/plugins/dex/order/keeper.go
@@ -609,9 +609,12 @@ func (kp *Keeper) doTransfer(ctx sdk.Context, tran *Transfer) sdk.Error {
 		panic(errors.New("unlocked tokens cannot cover the expense"))
 	}
 	account.SetLockedCoins(newLocked)
-	account.SetCoins(account.GetCoins().
-		Plus(sdk.Coins{sdk.NewCoin(tran.inAsset, tran.in)}).
-		Plus(sdk.Coins{sdk.NewCoin(tran.outAsset, tran.unlock-tran.out)}))
+	accountCoin := account.GetCoins().
+		Plus(sdk.Coins{sdk.NewCoin(tran.inAsset, tran.in)})
+	if remain := tran.unlock-tran.out; remain > 0 || !sdk.IsUpgrade(upgrade.FixZeroBalance) {
+		accountCoin = accountCoin.Plus(sdk.Coins{sdk.NewCoin(tran.outAsset, remain)})
+	}
+	account.SetCoins(accountCoin)
 
 	kp.am.SetAccount(ctx, account)
 	kp.logger.Debug("Performed Trade Allocation", "account", account, "allocation", tran.String())