From d2a0348a490ab2f3edc07f9ba4098f6e06bfefd1 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Fri, 1 Feb 2013 15:05:43 +0100
Subject: [PATCH] SYNC not allowed with pending data on the static output
 buffer.

---
 src/replication.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/replication.c b/src/replication.c
index ec36000b..4348dcfa 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -457,8 +457,8 @@ void syncCommand(redisClient *c) {
      * the client about already issued commands. We need a fresh reply
      * buffer registering the differences between the BGSAVE and the current
      * dataset, so that we can copy to other slaves if needed. */
-    if (listLength(c->reply) != 0) {
-        addReplyError(c,"SYNC and PSYNC are invalid with pending input");
+    if (listLength(c->reply) != 0 || c->bufpos != 0) {
+        addReplyError(c,"SYNC and PSYNC are invalid with pending output");
         return;
     }