[_562] release old connection when redirecting

When data objects were opened on redirected host connections, the
old connection was being leaked (overwritten without being properly released.)
The accumulation of irods.Connection object in source iRODSSession's active pool
caused agents to pile up rather than closing down and exiting as they should.
Eventually this caused a failure to connect from the client.

irods/manager/data_object_manager.py

@@ -428,6 +428,7 @@ def make_FileOpenRequest(**extra_opts):
                 # This is the actual redirect.
                 directed_sess = self.sess.clone(host = redirected_host)
                 returned_values['session'] = directed_sess
+                conn.release()
                 conn = directed_sess.pool.get_connection()
                 logger.debug('redirect_to_host = %s', redirected_host)
 

irods/test/data_obj_test.py

@@ -2081,6 +2081,26 @@ def test_touch_operation_does_not_work_when_given_a_collection__525(self):
         with self.assertRaises(ex.InvalidInputArgument):
             user_session.data_objects.touch(home_collection_path)
 
+    def test_client_redirect_lets_go_of_connections__issue_562(self):
+        self._skip_unless_connected_to_local_computer_by_other_than_localhost_synonym()
+        # Force data object connections to redirect by enforcing a non-equivalent hostname for their resource
+        with self.create_simple_resc(hostname = 'localhost') as resc_name:
+            REPS_TO_REPRODUCE_CONNECT_ERROR = 100
+            paths=[]
+            try:
+                # Try to exhaust connections
+                for n in range(REPS_TO_REPRODUCE_CONNECT_ERROR):
+                    data_path = '{self.coll_path}/issue_562_test_obj_{n:03d}.dat'.format(**locals())
+                    paths.append(data_path)
+                    with self.sess.data_objects.open(data_path, 'w', **{kw.DEST_RESC_NAME_KW: resc_name}) as f:
+                        pass
+            finally:
+                # Clean up data objects before resource is deleted.
+                for data_path in paths:
+                    if self.sess.data_objects.exists(data_path):
+                        self.sess.data_objects.unlink(data_path, force = True)
+                    else:
+                        break
 
 if __name__ == '__main__':
     # let the tests find the parent irods lib