From 6e6d81f094d5d99cd59bee1e57e7ab81d8ce5b05 Mon Sep 17 00:00:00 2001
From: Blake Mizerany <blake.mizerany@gmail.com>
Date: Fri, 22 Aug 2014 15:08:13 -0700
Subject: [PATCH] raft: copy ents to avoid races

---
 raft2/log.go | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/raft2/log.go b/raft2/log.go
index 54ed1f907..1fc331248 100644
--- a/raft2/log.go
+++ b/raft2/log.go
@@ -85,7 +85,13 @@ func (l *raftLog) findConflict(from int64, ents []Entry) int64 {
 }
 
 func (l *raftLog) unstableEnts() []Entry {
-	return l.entries(l.unstable)
+	ents := l.entries(l.unstable)
+	if ents == nil {
+		return nil
+	}
+	cpy := make([]Entry, len(ents))
+	copy(cpy, ents)
+	return cpy
 }
 
 func (l *raftLog) resetUnstable() {
@@ -96,7 +102,13 @@ func (l *raftLog) resetUnstable() {
 // all the returned entries will be marked as applied.
 func (l *raftLog) nextEnts() (ents []Entry) {
 	if l.committed > l.applied {
-		return l.slice(l.applied+1, l.committed+1)
+		ents := l.slice(l.applied+1, l.committed+1)
+		if ents == nil {
+			return nil
+		}
+		cpy := make([]Entry, len(ents))
+		copy(cpy, ents)
+		return cpy
 	}
 	return nil
 }