From 21abda0602e591991a2f1933018c113f0a85b9f6 Mon Sep 17 00:00:00 2001
From: Jae Kwon <jae@tendermint.com>
Date: Fri, 4 Dec 2015 00:59:26 -0800
Subject: [PATCH] Make Counter app return nil hash initially

---
 example/counter.go | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/example/counter.go b/example/counter.go
index d4b0e477..7b0ff1f8 100644
--- a/example/counter.go
+++ b/example/counter.go
@@ -68,10 +68,14 @@ func (appC *CounterAppContext) AppendTx(tx []byte) ([]types.Event, types.RetCode
 }
 
 func (appC *CounterAppContext) GetHash() ([]byte, types.RetCode) {
-	hash := make([]byte, 32)
-	binary.PutVarint(hash, int64(appC.txCount))
 	appC.hashCount += 1
-	return hash, 0
+	if appC.txCount == 0 {
+		return nil, 0
+	} else {
+		hash := make([]byte, 32)
+		binary.PutVarint(hash, int64(appC.txCount))
+		return hash, 0
+	}
 }
 
 func (appC *CounterAppContext) Commit() types.RetCode {