Fix waiting reply on empty queue.

redis.go

@@ -131,6 +131,10 @@ func (c *Client) Run(req Req) {
 }
 
 func (c *Client) RunQueued() ([]Req, error) {
+	if len(c.reqs) == 0 {
+		return c.reqs, nil
+	}
+
 	c.mtx.Lock()
 	reqs := c.reqs
 	c.reqs = make([]Req, 0)
@@ -177,6 +181,10 @@ func (c *Client) Discard() {
 }
 
 func (c *Client) Exec() ([]Req, error) {
+	if len(c.reqs) == 0 {
+		return c.reqs, nil
+	}
+
 	c.mtx.Lock()
 	reqs := c.reqs
 	c.reqs = make([]Req, 0)

redis_test.go

@@ -1372,6 +1372,12 @@ func (t *RedisTest) TestPipelining(c *C) {
 	c.Check(v, Equals, "bar2")
 }
 
+func (t *RedisTest) TestRunQueuedOnEmptyQueue(c *C) {
+	reqs, err := t.redisC.RunQueued()
+	c.Check(err, IsNil)
+	c.Check(reqs, HasLen, 0)
+}
+
 //------------------------------------------------------------------------------
 
 func (t *RedisTest) TestDiscard(c *C) {
@@ -1412,6 +1418,12 @@ func (t *RedisTest) TestMultiExec(c *C) {
 	c.Check(v, Equals, "bar")
 }
 
+func (t *RedisTest) TestExecOnEmptyQueue(c *C) {
+	reqs, err := t.redisC.Exec()
+	c.Check(err, IsNil)
+	c.Check(reqs, HasLen, 0)
+}
+
 //------------------------------------------------------------------------------
 
 func (t *RedisTest) TestConcAccess(c *C) {