From 10ebf1a335c0037dd9de2851dfcb9ec59c9d2e9b Mon Sep 17 00:00:00 2001
From: Xiang Li <xiang.li@coreos.com>
Date: Mon, 24 Nov 2014 16:36:59 -0800
Subject: [PATCH] raft: fix memoryStorage append

---
 raft/log.go     | 2 +-
 raft/storage.go | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/raft/log.go b/raft/log.go
index b13bd8b52..fd9ccdae1 100644
--- a/raft/log.go
+++ b/raft/log.go
@@ -81,7 +81,7 @@ func (l *raftLog) maybeAppend(index, logTerm, committed uint64, ents ...pb.Entry
 		switch {
 		case ci == 0:
 		case ci <= l.committed:
-			panic("conflict with committed entry")
+			log.Panicf("conflict(%d) with committed entry [committed(%d)]", ci, l.committed)
 		default:
 			l.append(ci-1, ents[ci-from:]...)
 		}
diff --git a/raft/storage.go b/raft/storage.go
index 94dddc498..9d62306e4 100644
--- a/raft/storage.go
+++ b/raft/storage.go
@@ -176,5 +176,12 @@ func (ms *MemoryStorage) Compact(i uint64, cs *pb.ConfState, data []byte) error
 func (ms *MemoryStorage) Append(entries []pb.Entry) {
 	ms.Lock()
 	defer ms.Unlock()
+	if len(entries) == 0 {
+		return
+	}
+	offset := entries[0].Index - ms.snapshot.Metadata.Index
+	if uint64(len(ms.ents)) >= offset {
+		ms.ents = ms.ents[:offset]
+	}
 	ms.ents = append(ms.ents, entries...)
 }