From 76a8cdcdaecb25cad58b015887e94a1393f6a425 Mon Sep 17 00:00:00 2001
From: Jakub Stasiak <jakub@stasiak.at>
Date: Tue, 28 Jan 2014 21:00:41 +0000
Subject: [PATCH] queue: Make join not wait if there are no unfinished tasks

This fixes GitHub issue #54
---
 eventlet/queue.py   | 3 ++-
 tests/queue_test.py | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/eventlet/queue.py b/eventlet/queue.py
index 77077cf..a8cafce 100644
--- a/eventlet/queue.py
+++ b/eventlet/queue.py
@@ -418,7 +418,8 @@ class Queue(LightQueue):
         that the item was retrieved and all work on it is complete. When the count of
         unfinished tasks drops to zero, :meth:`join` unblocks.
         '''
-        self._cond.wait()
+        if self.unfinished_tasks > 0:
+            self._cond.wait()
 
 
 class PriorityQueue(Queue):
diff --git a/tests/queue_test.py b/tests/queue_test.py
index 2135b19..43c28f5 100644
--- a/tests/queue_test.py
+++ b/tests/queue_test.py
@@ -253,6 +253,10 @@ class TestQueue(LimitedTestCase):
         assert channel.unfinished_tasks == 0, channel.unfinished_tasks
         gt.wait()
 
+    def test_join_doesnt_block_when_queue_is_already_empty(self):
+        queue = eventlet.Queue()
+        queue.join()
+
 
 def store_result(result, func, *args):
     try: