issue #156: don't decrement `waking` if we timed out rather than being woken.

docs/howitworks.rst

@@ -925,9 +925,9 @@ item.
     :py:meth:`mitogen.core.Latch.put`.
 
 **4. Wake, Non-empty**
-    On wake it re-acquires `lock`, removes itself from `sleeping`, decrementing
+    On wake it re-acquires `lock`, removes itself from `sleeping`, throws
-    `waking`, throws :py:class:`mitogen.core.TimeoutError` if no byte was
+    :py:class:`mitogen.core.TimeoutError` if no byte was written, decrements
-    written, otherwise pops and returns the first item in `queue` that is
+    `waking`,  then pops and returns the first item in `queue` that is
     guaranteed to exist.
 
 

mitogen/core.py

@@ -957,11 +957,11 @@ class Latch(object):
         self._lock.acquire()
         try:
             self._sleeping.remove(_tls.wsock)
-            self._waking -= 1
             if self.closed:
                 raise LatchError()
             if not rfds:
                 raise TimeoutError()
+            self._waking -= 1
             if _tls.rsock.recv(2) != '\x7f':
                 raise LatchError('internal error: received >1 wakeups')
             try: