From 8f51cfd7ce4d21dfc190298fefc889e260ee3a00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20Bry=C5=84ski?= <maciek-github@brynski.pl>
Date: Wed, 19 Jul 2017 22:28:09 +0200
Subject: [PATCH] Add Weakref to cloudpickle

https://github.com/cloudpipe/cloudpickle/pull/104/files
---
 python/pyspark/cloudpickle.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/python/pyspark/cloudpickle.py b/python/pyspark/cloudpickle.py
index 389bee7eee6e9..ade1751484fa1 100644
--- a/python/pyspark/cloudpickle.py
+++ b/python/pyspark/cloudpickle.py
@@ -667,6 +667,13 @@ def save_file(self, obj):
     else:
         dispatch[file] = save_file
 
+    # WeakSet was added in 2.7.
+    if hasattr(weakref, 'WeakSet'):
+        def save_weakset(self, obj):
+            self.save_reduce(weakref.WeakSet, (list(obj),))
+
+        dispatch[weakref.WeakSet] = save_weakset
+      
     """Special functions for Add-on libraries"""
 
     def inject_numpy(self):