change .poll for overridden panels instead of creating new classes

Needed to avoid errors disabling addons that have overridden panels

src/blenderbim/blenderbim/bim/__init__.py

@@ -23,6 +23,7 @@ import bpy.utils.previews
 import blenderbim
 import importlib
 from . import handler, ui, prop, operator, helper
+from typing import Callable, Union
 
 try:
     from blenderbim.translations import translations_dict
@@ -187,7 +188,7 @@ addon_keymaps = []
 icons = None
 is_registering = False
 last_commit_hash = "8888888"
-overridden_scene_panels = dict()
+original_scene_panels_polls: dict[bpy.types.Panel, Union[Callable, None]] = dict()
 
 
 def on_register(scene):
@@ -295,10 +296,17 @@ def unregister():
             km.keymap_items.remove(kmi)
     addon_keymaps.clear()
 
-    for panel in tuple(overridden_scene_panels.keys()):
+    for panel, poll in tuple(original_scene_panels_polls.items()):
-        original_panel, override_panel = overridden_scene_panels[panel]
+        if poll is None:
-        bpy.utils.unregister_class(override_panel)
+            del panel.poll
-        bpy.utils.register_class(original_panel)
+        else:
-        del overridden_scene_panels[panel]
+            panel.poll = poll
+        # panel might be already unregisterd during blender exit
+        # or if it's addon was disabled
+        if panel.is_registered:
+            # reregister to activate new poll
+            bpy.utils.unregister_class(panel)
+            bpy.utils.register_class(panel)
+        del original_scene_panels_polls[panel]
 
     bpy.app.translations.unregister("blenderbim")

src/blenderbim/blenderbim/bim/handler.py

@@ -260,34 +260,25 @@ def poll_check_blender_tab(cls, context):
     return tool.Blender.is_tab(context, "BLENDER")
 
 
-def get_override_scene_panel(panel_name):
+def override_scene_panel(original_panel: bpy.types.Panel) -> None:
-    original_panel = getattr(bpy.types, panel_name)
+    polls = blenderbim.bim.original_scene_panels_polls
-
-    override_panel = type(f"Override_{panel_name}", (original_panel,), {})
-    override_panel.bl_idname = f"{panel_name}_override"
-
-    # some blender panel depend on other and register_class will throw an error
-    # if we won't override their `bl_parent_id`
-    bl_parent_id = getattr(override_panel, "bl_parent_id", None)
-    if bl_parent_id is not None:
-        override_panel.bl_parent_id = f"{bl_parent_id}_override"
 
     # override poll method
-    poll = getattr(override_panel, "poll", None)
+    if not hasattr(original_panel, "poll"):
-    if poll is None:
+        polls[original_panel] = None
-        override_panel.poll = poll_check_blender_tab
+        original_panel.poll = poll_check_blender_tab
     else:
+        polls[original_panel] = original_panel.poll
 
         @classmethod
         def wrapped_poll(cls, context):
-            return super(override_panel, cls).poll(context) and poll_check_blender_tab.__func__(cls, context)
+            return polls[cls](context) and poll_check_blender_tab.__func__(cls, context)
 
-        override_panel.poll = wrapped_poll
+        original_panel.poll = wrapped_poll
 
-    return override_panel
+    # reregister to activate new poll
-
+    bpy.utils.unregister_class(original_panel)
-
+    bpy.utils.register_class(original_panel)
-OVERRIDE_SCENE_PANELS = tool.Blender.get_scene_panels_list()
 
 
 @persistent
@@ -328,12 +319,8 @@ def load_post(scene):
     # To improve usability for new users, we hijack the scene properties
     # tab. We override default scene properties panels with our own poll
     # to hide them unless the user has chosen to view Blender properties.
-    for panel in OVERRIDE_SCENE_PANELS:
+    for panel in tool.Blender.get_scene_panels_list():
-        if panel in blenderbim.bim.overridden_scene_panels:
+        if panel in blenderbim.bim.original_scene_panels_polls:
             continue
-        override_panel = get_override_scene_panel(panel)
+        override_scene_panel(panel)
-        original_panel = getattr(bpy.types, panel)
-        bpy.utils.register_class(override_panel)
-        bpy.utils.unregister_class(original_panel)
-        blenderbim.bim.overridden_scene_panels[panel] = (original_panel, override_panel)
     tool.Blender.setup_tabs()

src/blenderbim/blenderbim/tool/blender.py

@@ -877,7 +877,7 @@ class Blender(blenderbim.core.tool.Blender):
             pass
 
     @classmethod
-    def get_scene_panels_list(cls) -> tuple[str, ...]:
+    def get_scene_panels_list(cls) -> tuple[bpy.types.Panel, ...]:
         # example default blender scene panels can be found in
         # https://projects.blender.org/blender/blender/src/branch/main/scripts/startup/bl_ui/properties_scene.py#L421
         scene_panels: list[str] = []
@@ -887,6 +887,9 @@ class Blender(blenderbim.core.tool.Blender):
             # filter only panels
             if not hasattr(item, "bl_rna") or not isinstance(item.bl_rna, bpy.types.Panel):
                 continue
+            # ignore bbim panels
+            if item.__module__.startswith("blenderbim"):
+                continue
             # filter scene panels
             if getattr(item, "bl_context", None) != "scene":
                 continue
@@ -896,7 +899,8 @@ class Blender(blenderbim.core.tool.Blender):
                 panels_to_parents[item_name] = parent_panel
 
         scene_panels = cls.sort_panels_for_register(scene_panels, panels_to_parents)
-        return tuple(scene_panels)
+        final_panels = [getattr(bpy.types, p) for p in scene_panels]
+        return tuple(final_panels)
 
     @classmethod
     def sort_panels_for_register(cls, items: list[str], items_to_parents: dict[str, str]) -> list[str]: