From: A. Jesse Jiryu Davis <jesse@mongodb.com>
Date: Sat, 28 Feb 2015 18:35:36 +0000 (-0500)
Subject: Don't promise that coroutines waiting for a Lock are FIFO.
X-Git-Tag: v4.2.0b1~89^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30a80a09c2f1943e4c476eda26247efb5ce0bda3;p=thirdparty%2Ftornado.git

Don't promise that coroutines waiting for a Lock are FIFO.
---

diff --git a/tornado/locks.py b/tornado/locks.py
index c5ab59266..74aa898f9 100644
--- a/tornado/locks.py
+++ b/tornado/locks.py
@@ -264,9 +264,6 @@ class Lock(object):
     ...        pass
     ...
     ...    # Now the lock is released.
-
-    Coroutines waiting for `acquire` are granted the lock in first-in, first-out
-    order.
     """
     def __init__(self):
         self._block = BoundedSemaphore(value=1)
diff --git a/tornado/test/locks_test.py b/tornado/test/locks_test.py
index 6da82bc44..82504f992 100644
--- a/tornado/test/locks_test.py
+++ b/tornado/test/locks_test.py
@@ -382,22 +382,20 @@ class LockTests(AsyncTestCase):
         self.assertTrue(future.done())
 
     @gen_test
-    def test_acquire_fifo(self):
+    def test_acquire_contended(self):
         lock = locks.Lock()
         self.assertTrue(lock.acquire().done())
         N = 5
-        history = []
 
         @gen.coroutine
-        def f(idx):
+        def f():
             with (yield lock.acquire()):
-                history.append(idx)
+                pass
 
-        futures = [f(i) for i in range(N)]
+        futures = [f() for _ in range(N)]
         self.assertFalse(any(future.done() for future in futures))
         lock.release()
         yield futures
-        self.assertEqual(range(N), history)
 
     @gen_test
     def test_acquire_timeout(self):