From 027aac51724492798fd4875ba96dccccd9ac77ad 2014-12-06 15:13:43
From: Bussonnier Matthias <bussonniermatthias@gmail.com>
Date: 2014-12-06 15:13:43
Subject: [PATCH] lazy load widgets

Allow warnign to appear in notebook at the time widets get imported

---

diff --git a/IPython/kernel/zmq/ipkernel.py b/IPython/kernel/zmq/ipkernel.py
index 89d9677..0143d12 100644
--- a/IPython/kernel/zmq/ipkernel.py
+++ b/IPython/kernel/zmq/ipkernel.py
@@ -5,7 +5,6 @@ import sys
 import traceback
 
 from IPython.core import release
-from IPython.html.widgets import Widget
 from IPython.utils.py3compat import builtin_mod, PY3
 from IPython.utils.tokenutil import token_at_cursor, line_at_cursor
 from IPython.utils.traitlets import Instance, Type, Any
@@ -16,6 +15,12 @@ from .kernelbase import Kernel as KernelBase
 from .serialize import serialize_object, unpack_apply_message
 from .zmqshell import ZMQInteractiveShell
 
+
+def lazy_import_handle_comm_opened(*args, **kwargs):
+    from IPython.html.widgets import Widget
+    Widget.handle_comm_opened(*args, **kwargs)
+
+
 class IPythonKernel(KernelBase):
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     shell_class = Type(ZMQInteractiveShell)
@@ -59,7 +64,7 @@ class IPythonKernel(KernelBase):
 
         self.comm_manager = CommManager(shell=self.shell, parent=self, 
                                         kernel=self)
-        self.comm_manager.register_target('ipython.widget', Widget.handle_comm_opened)
+        self.comm_manager.register_target('ipython.widget', lazy_import_handle_comm_opened)
 
         self.shell.configurables.append(self.comm_manager)
         comm_msg_types = [ 'comm_open', 'comm_msg', 'comm_close' ]