Fix for waitall with nothing running

eventlet/greenpool.py

@@ -119,7 +119,8 @@ class GreenPool(object):
 
     def waitall(self):
         """Waits until all greenthreads in the pool are finished working."""
-        self.no_coros_running.wait()
+        if self.running():
+            self.no_coros_running.wait()
     
     def _spawn_done(self, coro):
         self.sem.release()
@@ -228,4 +229,4 @@ class GreenMap(GreenPile):
         try:
             return self.waiters.get().wait()
         finally:
-            self.counter -= 1
+            self.counter -= 1

tests/greenpool_test.py

@@ -297,6 +297,11 @@ class GreenPool(tests.LimitedTestCase):
         p = greenpool.GreenPool(4)
         result_list = list(p.starmap(passthru, [(x,) for x in xrange(10)]))
         self.assertEquals(result_list, range(10))
+
+    def test_waitall_on_nothing(self):
+        p = greenpool.GreenPool()
+        p.waitall()
+
             
 class GreenPile(tests.LimitedTestCase):
     def test_pile(self):
@@ -454,4 +459,4 @@ class Stress(tests.LimitedTestCase):
         subtest(50, 75, 100)
         for isize in (10, 20, 30, 40, 50):
             for psize in (5, 25, 35, 50):
-                subtest(isize, psize, psize)
+                subtest(isize, psize, psize)