From 5ca8c5bb83e412d8ca68c61f402e83d920a7f2eb Mon Sep 17 00:00:00 2001
From: Christopher Goes <cwgoes@pluranimity.org>
Date: Wed, 2 Jan 2019 19:17:27 +0100
Subject: [PATCH] Merge PR #3207: Fix token printing bug

* Add IsPositive, case check on coins[0]
* Link to correct PR
* Add testcase
---
 PENDING.md         | 1 +
 types/coin.go      | 7 ++++++-
 types/coin_test.go | 5 +++++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/PENDING.md b/PENDING.md
index 101a30650..82ce4ad66 100644
--- a/PENDING.md
+++ b/PENDING.md
@@ -19,6 +19,7 @@ BREAKING CHANGES
 
 * SDK
   * [\#3064](https://github.com/cosmos/cosmos-sdk/issues/3064) Sanitize `sdk.Coin` denom. Coins denoms are now case insensitive, i.e. 100fooToken equals to 100FOOTOKEN.
+  * \#3207 - Fix token printing bug
 
 * Tendermint
 
diff --git a/types/coin.go b/types/coin.go
index 365476327..e1ad00ec2 100644
--- a/types/coin.go
+++ b/types/coin.go
@@ -144,8 +144,13 @@ func (coins Coins) IsValid() bool {
 	case 1:
 		return coins[0].IsPositive()
 	default:
+		if strings.ToLower(coins[0].Denom) != coins[0].Denom {
+			return false
+		}
+		if !coins[0].IsPositive() {
+			return false
+		}
 		lowDenom := coins[0].Denom
-
 		for _, coin := range coins[1:] {
 			if strings.ToLower(coin.Denom) != coin.Denom {
 				return false
diff --git a/types/coin_test.go b/types/coin_test.go
index b5d6006d8..14d8925cc 100644
--- a/types/coin_test.go
+++ b/types/coin_test.go
@@ -286,6 +286,10 @@ func TestCoins(t *testing.T) {
 		{"gas", NewInt(1)},
 		{"mineral", NewInt(1)},
 	}
+	neg := Coins{
+		{"gas", NewInt(-1)},
+		{"mineral", NewInt(1)},
+	}
 
 	assert.True(t, good.IsValid(), "Coins are valid")
 	assert.False(t, mixedCase.IsValid(), "Coins denoms contain upper case characters")
@@ -298,6 +302,7 @@ func TestCoins(t *testing.T) {
 	assert.False(t, badSort2.IsValid(), "Coins are not sorted")
 	assert.False(t, badAmt.IsValid(), "Coins cannot include 0 amounts")
 	assert.False(t, dup.IsValid(), "Duplicate coin")
+	assert.False(t, neg.IsValid(), "Negative first-denom coin")
 }
 
 func TestCoinsGT(t *testing.T) {