From a8e25ab7c73b1a9fcddbb49f24ee8a93af81b8bf Mon Sep 17 00:00:00 2001
From: Alain Jobart <alainjobart@google.com>
Date: Wed, 6 Aug 2014 09:55:54 -0700
Subject: [PATCH] Adding a check to ShardMultiRestore.

---
 go/vt/wrangler/split.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/go/vt/wrangler/split.go b/go/vt/wrangler/split.go
index afbec3875c..19ec9f7b7d 100644
--- a/go/vt/wrangler/split.go
+++ b/go/vt/wrangler/split.go
@@ -134,6 +134,10 @@ func (wr *Wrangler) ShardMultiRestore(keyspace, shard string, sources []topo.Tab
 	mrErr := wr.SetSourceShards(keyspace, shard, sources, tables)
 	err = wr.unlockShard(keyspace, shard, actionNode, lockPath, mrErr)
 	if err != nil {
+		if mrErr != nil {
+			log.Errorf("unlockShard got error back: %v", err)
+			return mrErr
+		}
 		return err
 	}
 	if mrErr != nil {
@@ -171,6 +175,12 @@ func (wr *Wrangler) SetSourceShards(keyspace, shard string, sources []topo.Table
 		return err
 	}
 
+	// If the shard already has sources, maybe it's already been restored,
+	// so let's be safe and abort right here.
+	if len(shardInfo.SourceShards) > 0 {
+		return fmt.Errorf("Shard %v/%v already has SourceShards, not performing the MultiRestore")
+	}
+
 	// read the source tablets
 	sourceTablets, err := topo.GetTabletMap(wr.TopoServer(), sources)
 	if err != nil {