remove ResourceManager to fix leak of Transport/SSHClient

The back-reference from Transport to SSHClient was added because
the SSHClient had a destructor that would close the Transport,
and some users did not want the Transport closed when the SSHClient
was garbage collected.

The SSHClient destructor was not a normal destructor, it was
implemented with the ResourceManager singleton. Together with
the back-reference, this prevented the GC cycle detector from
freeing the SSHClient and Transport.

2 files changed, 0 insertions, 73 deletions

diff --git a/paramiko/client.py b/paramiko/client.py
index bbda1f80..025cf96c 100644
--- a/paramiko/client.py
+++ b/paramiko/client.py
@@ -34,7 +34,6 @@ from paramiko.dsskey import DSSKey
 from paramiko.ecdsakey import ECDSAKey
 from paramiko.hostkeys import HostKeys
 from paramiko.py3compat import string_types
-from paramiko.resource import ResourceManager
 from paramiko.rsakey import RSAKey
 from paramiko.ssh_exception import (
     SSHException, BadHostKeyException, NoValidConnectionsError
@@ -341,7 +340,6 @@ class SSHClient (ClosingContextManager):
             t.banner_timeout = banner_timeout
         t.start_client()
         t.set_sshclient(self)
-        ResourceManager.register(self, t)
 
         server_key = t.get_remote_server_key()
         keytype = server_key.get_name()
diff --git a/paramiko/resource.py b/paramiko/resource.py
deleted file mode 100644
index 5fed22ad..00000000
--- a/paramiko/resource.py
+++ /dev/null
@@ -1,71 +0,0 @@
-# Copyright (C) 2003-2007  Robey Pointer <robeypointer@gmail.com>
-#
-# This file is part of paramiko.
-#
-# Paramiko is free software; you can redistribute it and/or modify it under the
-# terms of the GNU Lesser General Public License as published by the Free
-# Software Foundation; either version 2.1 of the License, or (at your option)
-# any later version.
-#
-# Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
-# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
-# details.
-#
-# You should have received a copy of the GNU Lesser General Public License
-# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
-# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
-
-"""
-Resource manager.
-"""
-
-import weakref
-
-
-class ResourceManager (object):
-    """
-    A registry of objects and resources that should be closed when those
-    objects are deleted.
-
-    This is meant to be a safer alternative to Python's ``__del__`` method,
-    which can cause reference cycles to never be collected.  Objects registered
-    with the ResourceManager can be collected but still free resources when
-    they die.
-
-    Resources are registered using `register`, and when an object is garbage
-    collected, each registered resource is closed by having its ``close()``
-    method called.  Multiple resources may be registered per object, but a
-    resource will only be closed once, even if multiple objects register it.
-    (The last object to register it wins.)
-    """
-
-    def __init__(self):
-        self._table = {}
-
-    def register(self, obj, resource):
-        """
-        Register a resource to be closed with an object is collected.
-
-        When the given ``obj`` is garbage-collected by the Python interpreter,
-        the ``resource`` will be closed by having its ``close()`` method
-        called.  Any exceptions are ignored.
-
-        :param object obj: the object to track
-        :param object resource:
-            the resource to close when the object is collected
-        """
-        def callback(ref):
-            try:
-                resource.close()
-            except:
-                pass
-            del self._table[id(resource)]
-
-        # keep the weakref in a table so it sticks around long enough to get
-        # its callback called. :)
-        self._table[id(resource)] = weakref.ref(obj, callback)
-
-
-# singleton
-ResourceManager = ResourceManager()