Update ipywidgets for compatibility with latest bokeh

panel/io/ipywidget.py

@@ -1,17 +1,53 @@
 import logging
 
+import param
+
 from bokeh.document.events import MessageSentEvent
+from bokeh.document.json import MessageSent, Literal, TypedDict
+from bokeh.util.serialization import make_id
+
 from ipykernel.comm import CommManager
-from ipywidgets_bokeh.kernel import BokehKernel, SessionWebsocket, WebsocketStream
 from tornado.ioloop import IOLoop
+from ipywidgets_bokeh.kernel import BokehKernel, SessionWebsocket, WebsocketStream
+
+
+class MessageSentBuffers(TypedDict):
+    kind: Literal["MessageSent"]
+    msg_type: str
+
+
+class MessageSentEventPatched(MessageSentEvent):
+    """
+    Patches MessageSentEvent with fix that ensures MessageSent event
+    does not define msg_data (which is an assumption in BokehJS
+    Document.apply_json_patch.) 
+    """
+
+    def generate(self, references, buffers):
+        if not isinstance(self.msg_data, bytes):
+            msg = MessageSent(
+                kind=self.kind,
+                msg_type=self.msg_type,
+                msg_data=self.msg_data
+            )
+        else:
+            msg = MessageSentBuffers(
+                kind=self.kind,
+                msg_type=self.msg_type
+            )
+            assert buffers is not None
+            buffer_id = make_id()
+            buf = (dict(id=buffer_id), self.msg_data)
+            buffers.append(buf)
+        return msg
 
 
 class PanelSessionWebsocket(SessionWebsocket):
 
     def __init__(self, *args, **kwargs):
-        self._queue = []
         super().__init__(*args, **kwargs)
         self._document = kwargs.pop('document', None)
+        self._queue = []
         self._document.on_message("ipywidgets_bokeh", self.receive)
 
     def send(self, stream, msg_type, content=None, parent=None, ident=None, buffers=None, track=False, header=None, metadata=None):
@@ -37,25 +73,24 @@ def send(self, stream, msg_type, content=None, parent=None, ident=None, buffers=
         else:
             data = packed.decode("utf-8")
 
-        doc = self._document
-        event = MessageSentEvent(doc, "ipywidgets_bokeh", data)
+        event = MessageSentEventPatched(self._document, "ipywidgets_bokeh", data)
         self._queue.append(event)
-        doc.add_next_tick_callback(self._dispatch)
+        self._document.add_next_tick_callback(self._dispatch)
 
     def _dispatch(self):
         try:
             for event in self._queue:
                 self._document.callbacks.trigger_on_change(event)
-        except Exception:
-            pass
+        except Exception as e:
+            param.main.warning(f'ipywidgets event dispatch failed with: {e}')
         finally:
             self._queue = []
 
 
 class PanelKernel(BokehKernel):
 
     def __init__(self, key=None, document=None):
-        super(BokehKernel, self).__init__()
+        super().__init__()
 
         self.session = PanelSessionWebsocket(document=document, parent=self, key=key)
         self.stream = self.iopub_socket = WebsocketStream(self.session)

panel/pane/ipywidget.py

@@ -24,6 +24,12 @@ def _get_ipywidget(self, obj, doc, root, comm, **kwargs):
             import ipykernel
             from ipywidgets_bokeh.widget import IPyWidget
             from ..io.ipywidget import PanelKernel
+
+            # Patch font-awesome CSS
+            IPyWidget.__css__ = [
+                "https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/css/font-awesome.css"
+            ]
+
             if not isinstance(ipykernel.kernelbase.Kernel._instance, PanelKernel):
                 kernel = PanelKernel(document=doc, key=str(id(doc)).encode('utf-8'))
                 for w in obj.widgets.values():

panel/pane/plot.py

@@ -164,7 +164,7 @@ def __init__(self, object=None, **params):
         self._managers = {}
 
     def _get_widget(self, fig):
-        import matplotlib
+        import matplotlib.backends
         old_backend = getattr(matplotlib.backends, 'backend', 'agg')
 
         from ipympl.backend_nbagg import FigureManager, Canvas, is_interactive
@@ -193,6 +193,10 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
         props = self._process_param_change(self._init_params())
         kwargs = {k: v for k, v in props.items()
                   if k not in self._rerender_params+['interactive']}
+        w, h = self.object.get_size_inches()
+        kwargs['width'] = self.width or int(self.dpi * w)
+        kwargs['height'] = self.height or int(self.dpi * h)
+        kwargs['sizing_mode'] = self.sizing_mode
         model = self._get_ipywidget(manager.canvas, doc, root, comm,
                                     **kwargs)
         if root is None: