Upgrade to bokeh 2.4 and drop compatibility for older versions (#2739)

* Upgrade to bokeh 2.4 and drop compatibility for older versions

* Update package-lock.json

* Fix flakes

panel/io/embed.py

@@ -15,7 +15,6 @@
 from bokeh.models import CustomJS
 from param.parameterized import Watcher
 
-from ..util import doc_event_obj
 from .model import add_to_doc, diff
 from .state import state
 
@@ -302,8 +301,7 @@ def is_embeddable(object):
         values.append((ws, w_models, vals, getter))
 
     add_to_doc(model, doc, True)
-    event_obj = doc_event_obj(doc)
-    event_obj._held_events = []
+    doc.callbacks._held_events = []
 
     if not widget_data:
         return
@@ -338,13 +336,12 @@ def is_embeddable(object):
                 break
             sub_dict = sub_dict[g(m[0])]
         if skip:
-            event_obj._held_events = []
+            doc.callbacks._held_events = []
             continue
 
         # Drop events originating from widgets being varied
         models = [m for v in values for m in v[1]]
-        event_obj = doc_event_obj(doc)
-        event_obj._held_events = [e for e in event_obj._held_events if e.model not in models]
+        doc.callbacks._held_events = [e for e in doc.callbacks._held_events if e.model not in models]
         events = record_events(doc)
         changes |= events['content'] != '{}'
         if events:

panel/io/model.py

@@ -9,7 +9,6 @@
 from bokeh.models import Box, ColumnDataSource, Model
 from bokeh.protocol import Protocol
 
-from ..util import doc_event_obj
 from .state import state
 
 #---------------------------------------------------------------------
@@ -21,9 +20,8 @@ def diff(doc, binary=True, events=None):
     Returns a json diff required to update an existing plot with
     the latest plot data.
     """
-    event_obj = doc_event_obj(doc)
     if events is None:
-        events = list(event_obj._held_events)
+        events = list(doc.callbacks._held_events)
     if not events or state._hold:
         return None
 
@@ -33,7 +31,7 @@ def diff(doc, binary=True, events=None):
             and e.hint.cols is not None):
             e.hint.cols = None
     msg = Protocol().create("PATCH-DOC", events, use_buffers=binary)
-    event_obj._held_events = [e for e in event_obj._held_events if e not in events]
+    doc.callbacks._held_events = [e for e in doc.callbacks._held_events if e not in events]
     return msg
 
 
@@ -57,15 +55,13 @@ def add_to_doc(obj, doc, hold=False):
     # Add new root
     remove_root(obj)
     doc.add_root(obj)
-    event_obj = doc_event_obj(doc)
-    doc_hold = event_obj._hold
-    if doc_hold is None and hold:
+    if doc.callbacks.hold_value is None and hold:
         doc.hold()
 
+
 @contextmanager
 def hold(doc, policy='combine', comm=None):
-    event_obj = doc_event_obj(doc)
-    held = event_obj._hold
+    held = doc.callbacks.hold_value
     try:
         if policy is None:
             doc.unhold()
@@ -74,7 +70,7 @@ def hold(doc, policy='combine', comm=None):
         yield
     finally:
         if held:
-            event_obj._hold = held
+            doc.callbacks._hold = held
         else:
             if comm is not None:
                 from .notebook import push

panel/io/server.py

@@ -25,7 +25,7 @@
 
 # Bokeh imports
 from bokeh.application import Application as BkApplication
-from bokeh.application.handlers.code import CodeHandler
+from bokeh.application.handlers.code import CodeHandler, _monkeypatch_io, patch_curdoc
 from bokeh.application.handlers.function import FunctionHandler
 from bokeh.command.util import build_single_handler_application
 from bokeh.core.templates import AUTOLOAD_JS
@@ -47,9 +47,8 @@
 from tornado.wsgi import WSGIContainer
 
 # Internal imports
-from ..util import bokeh_version, doc_event_obj, edit_readonly
+from ..util import edit_readonly
 from .logging import LOG_SESSION_CREATED, LOG_SESSION_DESTROYED, LOG_SESSION_LAUNCHING
-
 from .profile import profile_ctx
 from .reload import autoreload_watcher
 from .resources import BASE_TEMPLATE, Resources, bundle_resources
@@ -300,18 +299,11 @@ def modify_document(self, doc):
     # stored modules are used to provide correct paths to
     # custom models resolver.
     sys.modules[module.__name__] = module
-    if bokeh_version >= '2.4.0':
-        doc.modules._modules.append(module)
-
-    else:
-        doc._modules.append(module)
+    doc.modules._modules.append(module)
 
     old_doc = curdoc()
     bk_set_curdoc(doc)
 
-    if bokeh_version < '2.4.0':
-        old_io = self._monkeypatch_io()
-
     if config.autoreload:
         set_curdoc(doc)
         state.onload(autoreload_watcher)
@@ -325,10 +317,7 @@ def post_check():
             # otherwise it will erroneously complain that there is
             # a memory leak
             if config.autoreload:
-                if bokeh_version >= '2.4.0':
-                    newdoc.modules._modules = []
-                else:
-                    newdoc._modules = []
+                newdoc.modules._modules = []
 
             # script is supposed to edit the doc not replace it
             if newdoc is not doc:
@@ -358,15 +347,10 @@ def handle_exception(handler, e):
             bokeh.application.handlers.code_runner.handle_exception = handle_exception
 
         state._launching.append(doc)
-        if bokeh_version >= '2.4.0':
-            from bokeh.application.handlers.code import _monkeypatch_io, patch_curdoc
-            with _monkeypatch_io(self._loggers):
-                with patch_curdoc(doc):
-                    with profile_ctx(config.profiler) as sessions:
-                        self._runner.run(module, post_check)
-        else:
-            with profile_ctx(config.profiler) as sessions:
-                self._runner.run(module, post_check)
+        with _monkeypatch_io(self._loggers):
+            with patch_curdoc(doc):
+                with profile_ctx(config.profiler) as sessions:
+                    self._runner.run(module, post_check)
 
         def _log_session_destroyed(session_context):
             logger.info(LOG_SESSION_DESTROYED, id(doc))
@@ -380,8 +364,6 @@ def _log_session_destroyed(session_context):
                 state.param.trigger('_profiles')
             except Exception:
                 pass
-        if bokeh_version < '2.4.0':
-            self._unmonkeypatch_io(old_io)
         bk_set_curdoc(old_doc)
 
 CodeHandler.modify_document = modify_document
@@ -452,10 +434,9 @@ def unlocked():
         return
     connections = curdoc.session_context.session._subscribed_connections
 
-    event_obj = doc_event_obj(curdoc)
-    hold = event_obj._hold
+    hold = curdoc.callbacks.hold_value
     if hold:
-        old_events = list(event_obj._held_events)
+        old_events = list(curdoc.callbacks._held_events)
     else:
         old_events = []
         curdoc.hold()
@@ -467,7 +448,7 @@ def unlocked():
             if hasattr(socket, 'write_lock') and socket.write_lock._block._value == 0:
                 state._locks.add(socket)
             locked = socket in state._locks
-            for event in event_obj._held_events:
+            for event in curdoc.callbacks._held_events:
                 if (isinstance(event, ModelChangedEvent) and event not in old_events
                     and hasattr(socket, 'write_message') and not locked):
                     msg = conn.protocol.create('PATCH-DOC', [event])
@@ -479,7 +460,7 @@ def unlocked():
                         WebSocketHandler.write_message(socket, payload, binary=True)
                 elif event not in events:
                     events.append(event)
-        event_obj._held_events = events
+        curdoc.callbacks._held_events = events
     finally:
         if not hold:
             curdoc.unhold()