From a9c34b679bad3deedb9dc2317e443b40489f7707 Mon Sep 17 00:00:00 2001
From: "sylvain.corlay" <sylvain.corlay@gmail.com>
Date: Sat, 26 Jul 2014 12:36:21 -0400
Subject: [PATCH 1/4] decoupling the comm lifetime from the widget lifetime

---
 IPython/html/widgets/widget.py | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/IPython/html/widgets/widget.py b/IPython/html/widgets/widget.py
index 345a4c7ec..3d1df8408 100644
--- a/IPython/html/widgets/widget.py
+++ b/IPython/html/widgets/widget.py
@@ -127,6 +127,8 @@ class Widget(LoggingConfigurable):
     def __del__(self):
         """Object disposal"""
         self.close()
+        del Widget.widgets[self.model_id]
+        self._comm = None
 
     #-------------------------------------------------------------------------
     # Properties
@@ -141,7 +143,6 @@ class Widget(LoggingConfigurable):
             # Create a comm.
             self._comm = Comm(target_name=self._model_name)
             self._comm.on_msg(self._handle_msg)
-            self._comm.on_close(self._close)
             Widget.widgets[self.model_id] = self
 
             # first update
@@ -158,20 +159,15 @@ class Widget(LoggingConfigurable):
     #-------------------------------------------------------------------------
     # Methods
     #-------------------------------------------------------------------------
-    def _close(self):
-        """Private close - cleanup objects, registry entries"""
-        del Widget.widgets[self.model_id]
-        self._comm = None
 
     def close(self):
         """Close method.
 
-        Closes the widget which closes the underlying comm.
+        Closes the underlying comm.
         When the comm is closed, all of the widget views are automatically
         removed from the front-end."""
         if self._comm is not None:
             self._comm.close()
-            self._close()
 
     def send_state(self, key=None):
         """Sends the widget state, or a piece of it, to the front-end.

From 2c648fe4d09dfeda6ae007f3725c3b4f44172bcc Mon Sep 17 00:00:00 2001
From: Sylvain Corlay <scorlay@bloomberg.net>
Date: Tue, 29 Jul 2014 20:11:34 +0000
Subject: [PATCH 2/4] bad call and missing call to unregister_comm

---
 IPython/html/static/services/kernels/js/comm.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/IPython/html/static/services/kernels/js/comm.js b/IPython/html/static/services/kernels/js/comm.js
index 4cb24a6fa..04307cf40 100644
--- a/IPython/html/static/services/kernels/js/comm.js
+++ b/IPython/html/static/services/kernels/js/comm.js
@@ -56,9 +56,9 @@ define([
         return comm.comm_id;
     };
     
-    CommManager.prototype.unregister_comm = function (comm_id) {
+    CommManager.prototype.unregister_comm = function (comm) {
         // Remove a comm from the mapping
-        delete this.comms[comm_id];
+        delete this.comms[comm.comm_id];
     };
     
     // comm message handlers
@@ -88,7 +88,7 @@ define([
         if (comm === undefined) {
             return;
         }
-        delete this.comms[content.comm_id];
+        this.unregister_comm(comm);
         try {
             comm.handle_close(msg);
         } catch (e) {

From ea52ef870475883ec108767d8f183b8f9afaedb1 Mon Sep 17 00:00:00 2001
From: Sylvain Corlay <scorlay@bloomberg.net>
Date: Wed, 30 Jul 2014 00:28:30 +0000
Subject: [PATCH 3/4] del Widget.widgets[seld.model_id] in close rather than in
 __del__

---
 IPython/html/widgets/widget.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/IPython/html/widgets/widget.py b/IPython/html/widgets/widget.py
index 3d1df8408..3a72d0de1 100644
--- a/IPython/html/widgets/widget.py
+++ b/IPython/html/widgets/widget.py
@@ -127,8 +127,6 @@ class Widget(LoggingConfigurable):
     def __del__(self):
         """Object disposal"""
         self.close()
-        del Widget.widgets[self.model_id]
-        self._comm = None
 
     #-------------------------------------------------------------------------
     # Properties
@@ -166,9 +164,10 @@ class Widget(LoggingConfigurable):
         Closes the underlying comm.
         When the comm is closed, all of the widget views are automatically
         removed from the front-end."""
+        del Widget.widgets[self.model_id]
         if self._comm is not None:
             self._comm.close()
-
+    
     def send_state(self, key=None):
         """Sends the widget state, or a piece of it, to the front-end.
 

From 1bbc915ac0b0ff6b24d7655c9d48dfdd3392ffd0 Mon Sep 17 00:00:00 2001
From: Sylvain Corlay <sylvain.corlay@gmail.com>
Date: Wed, 30 Jul 2014 23:16:24 -0400
Subject: [PATCH 4/4] setting _comm to None

---
 IPython/html/widgets/widget.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/IPython/html/widgets/widget.py b/IPython/html/widgets/widget.py
index 3a72d0de1..745e7d60f 100644
--- a/IPython/html/widgets/widget.py
+++ b/IPython/html/widgets/widget.py
@@ -167,6 +167,7 @@ class Widget(LoggingConfigurable):
         del Widget.widgets[self.model_id]
         if self._comm is not None:
             self._comm.close()
+        self._comm = None
     
     def send_state(self, key=None):
         """Sends the widget state, or a piece of it, to the front-end.