add on_ready_counter to reduction

billiard/pool.py

@@ -271,6 +271,7 @@ def __reduce__(self):
             self.inq, self.outq, self.synq, self.initializer,
             self.initargs, self.maxtasks, self._shutdown, self.on_exit,
             self.sigprotection, self.wrap_exception, self.max_memory_per_child,
+            self.on_ready_counter
         )
 
     def __call__(self):

t/unit/test_pool.py

@@ -1,4 +1,5 @@
 import billiard.pool
+from billiard import get_context
 import time
 import pytest
 
@@ -9,6 +10,12 @@ def func(x):
     return x
 
 
+def get_on_ready_count():
+    import inspect
+    worker = inspect.stack()[1].frame.f_locals['self']
+    return worker.on_ready_counter.value
+
+
 class test_pool:
     def test_raises(self):
         pool = billiard.pool.Pool()
@@ -39,3 +46,13 @@ def test_exception_traceback_present(self):
             if i == 2:
                 with pytest.raises(ValueError):
                     res.get()
+
+    def test_on_ready_counter_is_synchronized(self):
+        for ctx in ('spawn', 'fork', 'forkserver'):
+            pool = billiard.pool.Pool(processes=1, context=get_context(ctx))
+            pool.apply_async(func, (1,)).get(1)
+            on_ready_counter = pool.apply_async(get_on_ready_count, ).get(1)
+            assert on_ready_counter == 1
+            pool.close()
+            pool.join()
+            pool.terminate()