Issue #223: Fix threading monkey-patching on py3.4

Fix the monkey-patching of the threading module on Python 3.4. Instead
of removing the thread state lock, patch the _bootstrap_inner() method
to release it.

eventlet/green/thread.py

@@ -52,10 +52,20 @@ def start_new_thread(function, args=(), kwargs=None):
         # With monkey patching, eventlet uses green threads without python
         # thread state, so the lock is not automatically released.
         #
-        # Disable the thread state lock to avoid dead locks.
+        # Wrap _bootstrap_inner() to release explicitly the thread state lock
+        # when the thread completes.
         thread = function.__self__
-        thread._set_tstate_lock = lambda: None
-        thread._wait_for_tstate_lock = lambda *args, **kw: None
+        bootstrap_inner = thread._bootstrap_inner
+
+        def wrap_bootstrap_inner():
+            try:
+                bootstrap_inner()
+            finally:
+                # The lock can be cleared (ex: by a fork())
+                if thread._tstate_lock is not None:
+                    thread._tstate_lock.release()
+
+        thread._bootstrap_inner = wrap_bootstrap_inner
 
     kwargs = kwargs or {}
     g = greenthread.spawn_n(__thread_body, function, args, kwargs)

tests/isolated/patcher_threading_join.py

@@ -0,0 +1,23 @@
+# Issue #223: test threading.Thread.join with monkey-patching
+import eventlet
+
+# no standard tests in this file, ignore
+__test__ = False
+
+
+if __name__ == '__main__':
+    eventlet.monkey_patch()
+
+    import threading
+    import time
+
+    sleeper = threading.Thread(target=time.sleep, args=(1,))
+    start = time.time()
+    sleeper.start()
+    sleeper.join()
+    dt = time.time() - start
+
+    if dt < 1.0:
+        raise Exception("test failed: dt=%s" % dt)
+
+    print('pass')

tests/patcher_test.py

@@ -502,3 +502,7 @@ def test_importlib_lock():
 
 def test_threading_condition():
     tests.run_isolated('patcher_threading_condition.py')
+
+
+def test_threading_join():
+    tests.run_isolated('patcher_threading_join.py')