[BRANCH-0.4.x] FIX pickle RootLogger

cloudpickle/cloudpickle.py

@@ -819,6 +819,11 @@ def save_logger(self, obj):
 
     dispatch[logging.Logger] = save_logger
 
+    def save_root_logger(self, obj):
+        self.save_reduce(logging.getLogger, (), obj=obj)
+
+    dispatch[logging.RootLogger] = save_root_logger
+
     """Special functions for Add-on libraries"""
     def inject_addons(self):
         """Plug in system. Register additional pickling functions if modules already loaded"""

tests/cloudpickle_test.py

@@ -588,8 +588,8 @@ def test_cell_manipulation(self):
             msg='cell contents not set correctly',
         )
 
-    def test_logger(self):
-        logger = logging.getLogger('cloudpickle.dummy_test_logger')
+    def check_logger(self, name):
+        logger = logging.getLogger(name)
         pickled = pickle_depickle(logger)
         self.assertTrue(pickled is logger, (pickled, logger))
 
@@ -608,7 +608,13 @@ def test_logger(self):
         out, _ = proc.communicate()
         self.assertEqual(proc.wait(), 0)
         self.assertEqual(out.strip().decode(),
-                         'INFO:cloudpickle.dummy_test_logger:hello')
+                         'INFO:{}:hello'.format(logger.name))
+
+    def test_logger(self):
+        # logging.RootLogger object
+        self.check_logger(None)
+        # logging.Logger object
+        self.check_logger('cloudpickle.dummy_test_logger')
 
     def test_abc(self):