Change _instances from 'global' variable to class variable.

Author: Alan Fleming

python/ipywidgets/ipywidgets/embed.py

@@ -12,7 +12,7 @@
 
 import json
 import re
-from .widgets import Widget, DOMWidget, widget as widget_module
+from .widgets import Widget, DOMWidget
 from .widgets.widget_link import Link
 from .widgets.docutils import doc_subst
 from ._version import __html_manager_version__
@@ -129,7 +129,7 @@ def _get_recursive_state(widget, store=None, drop_defaults=False):
 
 def add_resolved_links(store, drop_defaults):
     """Adds the state of any link models between two models in store"""
-    for widget_id, widget in widget_module._instances.items(): # go over all widgets
+    for widget_id, widget in Widget._instances.items(): # go over all widgets
         if isinstance(widget, Link) and widget_id not in store:
             if widget.source[0].model_id in store and widget.target[0].model_id in store:
                 store[widget.model_id] = widget._get_embed_state(drop_defaults=drop_defaults)
@@ -207,7 +207,7 @@ def embed_data(views, drop_defaults=True, state=None):
         view_specs: a list of widget view specs
     """
     if views is None:
-        views = [w for w in widget_module._instances.values() if isinstance(w, DOMWidget)]
+        views = [w for w in Widget._instances.values() if isinstance(w, DOMWidget)]
     else:
         try:
             views[0]

python/ipywidgets/ipywidgets/tests/test_embed.py

@@ -9,7 +9,7 @@
 
 import traitlets
 
-from ..widgets import IntSlider, IntText, Text, Widget, jslink, HBox, widget_serialization, widget as widget_module
+from ..widgets import IntSlider, IntText, Text, Widget, jslink, HBox, widget_serialization
 from ..embed import embed_data, embed_snippet, embed_minimal_html, dependency_state
 
 
@@ -29,7 +29,7 @@ class CaseWidget(Widget):
 class TestEmbed:
 
     def teardown(self):
-        for w in tuple(widget_module._instances.values()):
+        for w in tuple(Widget._instances.values()):
             w.close()
 
     def test_embed_data_simple(self):

python/ipywidgets/ipywidgets/widgets/tests/test_widget.py

@@ -5,7 +5,6 @@
 
 import copy
 import gc
-import inspect
 import weakref
 
 import pytest
@@ -15,7 +14,6 @@
 
 import ipywidgets as ipw
 
-from .. import widget
 from ..widget import Widget
 from ..widget_button import Button
 
@@ -62,29 +60,12 @@ def test_close_all():
     # create a couple of widgets
     widgets = [Button() for i in range(10)]
 
-    assert len(widget._instances) > 0, "expect active widgets"
-    assert widget._instances[widgets[0].model_id] is widgets[0]
+    assert len(Widget._instances) > 0, "expect active widgets"
+    assert Widget._instances[widgets[0].model_id] is widgets[0]
     # close all the widgets
     Widget.close_all()
 
-    assert len(widget._instances) == 0, "active widgets should be cleared"
-
-
-def test_compatibility():
-    button = Button()
-    assert widget._instances[button.model_id] is button
-    with pytest.deprecated_call() as record:
-        assert widget._instances is widget.Widget.widgets
-        assert widget._instances is widget.Widget._active_widgets
-        assert widget._registry is widget.Widget.widget_types
-        assert widget._registry is widget.Widget._widget_types
-
-        Widget.close_all()
-        assert not widget.Widget.widgets
-        assert not widget.Widget._active_widgets
-    caller_path = inspect.stack(context=0)[1].filename
-    assert all(x.filename == caller_path for x in record)
-    assert len(record) == 6
+    assert len(Widget._instances) == 0, "active widgets should be cleared"
 
 
 def test_widget_copy():
@@ -98,12 +79,12 @@ def test_widget_copy():
 def test_widget_open():
     button = Button()
     model_id = button.model_id
-    assert model_id in widget._instances
+    assert model_id in Widget._instances
     spec = button.get_view_spec()
     assert list(spec) == ["version_major", "version_minor", "model_id"]
     assert spec["model_id"]
     button.close()
-    assert model_id not in widget._instances
+    assert model_id not in Widget._instances
     with pytest.raises(RuntimeError, match="Widget is closed"):
         button.open()
     with pytest.raises(RuntimeError, match="Widget is closed"):
@@ -225,7 +206,7 @@ def my_click(self, b):
         b = TestButton(description="button")
         weakref.finalize(b, on_delete)
         b_ref = weakref.ref(b)
-        assert b in widget._instances.values()
+        assert b in Widget._instances.values()
 
         b.on_click(b.my_click)
         b.on_click(lambda x: setattr(x, "clicked", True))
@@ -235,11 +216,11 @@ def my_click(self, b):
 
         if weakref_enabled:
             ipw.enable_weakreference()
-            assert b in widget._instances.values(), "Instances not transferred"
+            assert b in Widget._instances.values(), "Instances not transferred"
             ipw.disable_weakreference()
-            assert b in widget._instances.values(), "Instances not transferred"
+            assert b in Widget._instances.values(), "Instances not transferred"
             ipw.enable_weakreference()
-            assert b in widget._instances.values(), "Instances not transferred"
+            assert b in Widget._instances.values(), "Instances not transferred"
 
         b.click()
         assert click_count == 2
@@ -251,7 +232,7 @@ def my_click(self, b):
             assert deleted
         else:
             assert not deleted
-            assert b_ref() in widget._instances.values()
+            assert b_ref() in Widget._instances.values()
             b_ref().close()
             gc.collect()
             assert deleted, "Closing should remove the last strong reference."

python/ipywidgets/ipywidgets/widgets/tests/test_widget_box.py

@@ -57,7 +57,6 @@ def test_box_validate_mode():
 
 
 def test_box_gc():
-    widgets.VBox._active_widgets
     widgets.enable_weakreference()
     # Test Box gc collected and children lifecycle managed.
     try:
@@ -80,6 +79,5 @@ def on_delete():
         del b
         gc.collect()
         assert deleted
-        widgets.VBox._active_widgets
     finally:
         widgets.disable_weakreference()

python/ipywidgets/ipywidgets/widgets/widget.py

@@ -19,8 +19,6 @@
 
 from base64 import standard_b64encode
 
-from .utils import deprecation, _get_frame
-
 from .._version import __protocol_version__, __control_protocol_version__, __jupyter_widgets_base_version__
 
 import inspect
@@ -43,29 +41,24 @@ def envset(name, default):
 JUPYTER_WIDGETS_ECHO = envset('JUPYTER_WIDGETS_ECHO', default=True)
 # for a discussion on using weak references see:
 #  https://github.com/jupyter-widgets/ipywidgets/issues/1345
-_instances : typing.MutableMapping[str, "Widget"] = {}
 
 def enable_weakreference():
-    """Use a WeakValueDictionary instead of a standard dictionary to map 
-    `comm_id` to `widget` for every widget instance.
+    """Use a WeakValueDictionary to store references to Widget instances.
 
-    By default widgets are mapped using a standard dictionary. Use this feature
-    to permit widget garbage collection. 
+    A strong reference must be kept to widgets. 
     """
-    global _instances
-    if not isinstance(_instances, weakref.WeakValueDictionary):
-        _instances  = weakref.WeakValueDictionary(_instances)
+    if not isinstance(Widget._instances, weakref.WeakValueDictionary):
+        Widget._instances = weakref.WeakValueDictionary(Widget._instances)
 
 def disable_weakreference():
-    """Use a Dictionary to map `comm_id` to `widget` for every widget instance.
-    
-    Note: this is the default setting and maintains a strong reference to the 
-    the widget preventing automatic garbage collection. If the close method
-    is called, the widget will remove itself enabling garbage collection.
+    """Use a standard dictionary to store references to Widget instances (default behavior).
+
+    Note: this is the default setting and maintains a strong reference to the
+    the widget preventing automatic garbage collection. When the widget is closed
+    it can be garbage collected.
     """
-    global _instances
-    if  isinstance(_instances, weakref.WeakValueDictionary):
-        _instances  = dict(_instances)
+    if isinstance(Widget._instances, weakref.WeakValueDictionary):
+        Widget._instances = dict(Widget._instances)
 
 def _widget_to_json(x, obj):
     if isinstance(x, Widget):
@@ -82,8 +75,8 @@ def _json_to_widget(x, obj):
         return {k: _json_to_widget(v, obj) for k, v in x.items()}
     elif isinstance(x, (list, tuple)):
         return [_json_to_widget(v, obj) for v in x]
-    elif isinstance(x, str) and x.startswith('IPY_MODEL_') and x[10:] in _instances:
-        return _instances[x[10:]]
+    elif isinstance(x, str) and x.startswith("IPY_MODEL_") and x[10:] in Widget._instances:
+        return Widget._instances[x[10:]]
     else:
         return x
 
@@ -314,50 +307,12 @@ class Widget(LoggingHasTraits):
     #-------------------------------------------------------------------------
     _widget_construction_callback = None
     _control_comm = None
-    
-    @_staticproperty
-    def widgets():
-        # Because this is a static attribute, it will be accessed when initializing this class. In that case, since a user
-        # did not explicitly try to use this attribute, we do not want to throw a deprecation warning.
-        # So we check if the thing calling this static property is one of the known initialization functions in traitlets.
-        frame = _get_frame(2)
-        if not (frame.f_code.co_filename == TRAITLETS_FILE and (frame.f_code.co_name in ('getmembers', 'setup_instance', 'setup_class'))):
-            deprecation("Widget.widgets is deprecated.")
-        return _instances
-
-    @_staticproperty
-    def _active_widgets():
-        # Because this is a static attribute, it will be accessed when initializing this class. In that case, since a user
-        # did not explicitly try to use this attribute, we do not want to throw a deprecation warning.
-        # So we check if the thing calling this static property is one of the known initialization functions in traitlets.
-        frame = _get_frame(2)
-        if not (frame.f_code.co_filename == TRAITLETS_FILE and (frame.f_code.co_name in ('getmembers', 'setup_instance', 'setup_class'))):
-            deprecation("Widget._active_widgets is deprecated.")
-        return _instances
-
-    @_staticproperty
-    def _widget_types():
-        # Because this is a static attribute, it will be accessed when initializing this class. In that case, since a user
-        # did not explicitly try to use this attribute, we do not want to throw a deprecation warning.
-        # So we check if the thing calling this static property is one of the known initialization functions in traitlets.
-        frame = _get_frame(2)
-        if not (frame.f_code.co_filename == TRAITLETS_FILE and (frame.f_code.co_name in ('getmembers', 'setup_instance', 'setup_class'))):
-            deprecation("Widget._widget_types is deprecated.")
-        return _registry
-
-    @_staticproperty
-    def widget_types():
-        # Because this is a static attribute, it will be accessed when initializing this class. In that case, since a user
-        # did not explicitly try to use this attribute, we do not want to throw a deprecation warning.
-        # So we check if the thing calling this static property is one of the known initialization functions in traitlets.
-        frame = _get_frame(2)
-        if not (frame.f_code.co_filename == TRAITLETS_FILE and (frame.f_code.co_name in ('getmembers', 'setup_instance', 'setup_class'))):
-            deprecation("Widget.widget_types is deprecated.")
-        return _registry
+
+    _instances: typing.ClassVar[typing.MutableMapping[str, "Widget"]] = {}
 
     @classmethod
     def close_all(cls):
-        for widget in list(_instances.values()):
+        for widget in list(Widget._instances.values()):
             widget.close()
 
     @staticmethod
@@ -399,7 +354,7 @@ def _handle_control_comm_msg(cls, msg):
         if method == 'request_states':
             # Send back the full widgets state
             cls.get_manager_state()
-            widgets = _instances.values()
+            widgets = cls._instances.values()
             full_state = {}
             drop_defaults = False
             for widget in widgets:
@@ -440,8 +395,8 @@ def handle_comm_opened(comm, msg):
             _put_buffers(state, data['buffer_paths'], msg['buffers'])
         widget.set_state(state)
 
-    @staticmethod
-    def get_manager_state(drop_defaults=False, widgets=None):
+    @classmethod
+    def get_manager_state(cls, drop_defaults=False, widgets=None):
         """Returns the full state for a widget manager for embedding
 
         :param drop_defaults: when True, it will not include default value
@@ -450,7 +405,7 @@ def get_manager_state(drop_defaults=False, widgets=None):
         """
         state = {}
         if widgets is None:
-            widgets = _instances.values()
+            widgets = cls._instances.values()
         for widget in widgets:
             state[widget.model_id] = widget._get_embed_state(drop_defaults=drop_defaults)
         return {'version_major': 2, 'version_minor': 0, 'state': state}
@@ -561,14 +516,11 @@ def _comm_changed(self, change):
         if change['old']:
             change['old'].on_msg(None)
             change['old'].close()
-            # On python shutdown _instances can be None
-            if isinstance(_instances, dict):
-                _instances.pop(change['old'].comm_id, None)
+            self._instances.pop(change['old'].comm_id, None)
         if change['new']:
-            if isinstance(_instances, dict):
-                _instances[change["new"].comm_id] = self
-                self._model_id = change["new"].comm_id
-            
+            self._instances[change["new"].comm_id] = self
+            self._model_id = change["new"].comm_id
+
             # prevent memory leaks by using a weak reference to self.
             ref = weakref.ref(self)
             def _handle_msg(msg):

python/ipywidgets/setup.cfg

@@ -23,6 +23,8 @@ classifiers =
   Programming Language :: Python :: 3.9
   Programming Language :: Python :: 3.10
   Programming Language :: Python :: 3.11
+  Programming Language :: Python :: 3.12
+  Programming Language :: Python :: 3.13
   Programming Language :: Python :: 3 :: Only
   Framework :: Jupyter