From: Guido van Rossum <guido@dropbox.com>
Date: Thu, 21 Nov 2013 19:07:45 +0000 (-0800)
Subject: asyncio: Make Semaphore(0) work properly.
X-Git-Tag: v3.4.0b1~145
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9c55a58a1d7f664e7d236ef690d17409841632c4;p=thirdparty%2FPython%2Fcpython.git

asyncio: Make Semaphore(0) work properly.
---

diff --git a/Lib/asyncio/locks.py b/Lib/asyncio/locks.py
index ac851e5cc4b4..dd9f0f8b4fa7 100644
--- a/Lib/asyncio/locks.py
+++ b/Lib/asyncio/locks.py
@@ -348,12 +348,12 @@ class Semaphore:
 
     def __init__(self, value=1, bound=False, *, loop=None):
         if value < 0:
-            raise ValueError("Semaphore initial value must be > 0")
+            raise ValueError("Semaphore initial value must be >= 0")
         self._value = value
         self._bound = bound
         self._bound_value = value
         self._waiters = collections.deque()
-        self._locked = False
+        self._locked = (value == 0)
         if loop is not None:
             self._loop = loop
         else:
diff --git a/Lib/test/test_asyncio/test_locks.py b/Lib/test/test_asyncio/test_locks.py
index 19ef877af027..539c5c38ee3a 100644
--- a/Lib/test/test_asyncio/test_locks.py
+++ b/Lib/test/test_asyncio/test_locks.py
@@ -684,6 +684,10 @@ class SemaphoreTests(unittest.TestCase):
         finally:
             events.set_event_loop(None)
 
+    def test_initial_value_zero(self):
+        sem = locks.Semaphore(0, loop=self.loop)
+        self.assertTrue(sem.locked())
+
     def test_repr(self):
         sem = locks.Semaphore(loop=self.loop)
         self.assertTrue(repr(sem).endswith('[unlocked,value:1]>'))