From: antirez <antirez@gmail.com>
Date: Mon, 16 Jan 2012 10:27:22 +0000 (+0100)
Subject: Don't change the replication state if SLAVE OF is called with arguments specifying... 
X-Git-Url: https://git.saurik.com/redis.git/commitdiff_plain/ebdfad69dce1b3a1a48960328e5f6c3ed8fafa41?ds=sidebyside

Don't change the replication state if SLAVE OF is called with arguments specifying the same master we are already connected with. This fixes issues #290.
---

diff --git a/src/replication.c b/src/replication.c
index 479dcf43..dd42fcf1 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -517,9 +517,23 @@ void slaveofCommand(redisClient *c) {
             redisLog(REDIS_NOTICE,"MASTER MODE enabled (user request)");
         }
     } else {
+        long port;
+
+        if ((getLongFromObjectOrReply(c, c->argv[2], &port, NULL) != REDIS_OK))
+            return;
+
+        /* Check if we are already attached to the specified slave */
+        if (server.masterhost && !strcasecmp(server.masterhost,c->argv[1]->ptr)
+            && server.masterport == port) {
+            redisLog(REDIS_NOTICE,"SLAVE OF would result into synchronization with the master we are already connected with. No operation performed.");
+            addReplySds(c,sdsnew("+OK Already connected to specified master\r\n"));
+            return;
+        }
+        /* There was no previous master or the user specified a different one,
+         * we can continue. */
         sdsfree(server.masterhost);
         server.masterhost = sdsdup(c->argv[1]->ptr);
-        server.masterport = atoi(c->argv[2]->ptr);
+        server.masterport = port;
         if (server.master) freeClient(server.master);
         if (server.repl_state == REDIS_REPL_TRANSFER)
             replicationAbortSyncTransfer();