Fix monkey_patch() on Python 3

The importlib module must use real thread locks, not eventlet.Semaphore.

eventlet/patcher.py

@@ -283,6 +283,12 @@ def monkey_patch(**on):
     finally:
         imp.release_lock()
 
+    if sys.version_info >= (3, 3):
+        import importlib._bootstrap
+        thread = original('_thread')
+        # importlib must use real thread locks, not eventlet.Semaphore
+        importlib._bootstrap._thread = thread
+
 
 def is_monkey_patched(module):
     """Returns True if the given module is monkeypatched currently, False if

tests/patcher_test.py

@@ -492,5 +492,10 @@ t2.join()
         self.assertEqual(lines[1], "True", lines[1])
 
 
+def test_importlib_lock():
+    output = run_python('tests/patcher_test_importlib_lock.py')
+    assert output.rstrip() == b'ok'
+
+
 if __name__ == '__main__':
     main()

tests/patcher_test_importlib_lock.py

@@ -0,0 +1,30 @@
+from __future__ import print_function
+
+import sys
+
+import eventlet
+
+
+# no standard tests in this file, ignore
+__test__ = False
+
+
+def do_import():
+    import encodings.idna
+
+
+if __name__ == '__main__':
+    eventlet.monkey_patch()
+    threading = eventlet.patcher.original('threading')
+
+    sys.modules.pop('encodings.idna', None)
+
+    # call "import encodings.idna" in a new thread
+    thread = threading.Thread(target=do_import)
+    thread.start()
+
+    # call "import encodings.idna" in the main thread
+    do_import()
+
+    thread.join()
+    print('ok')