Backport pending-opening-cuts banner from gh8088

Extract the pending_opening_recut tracking, three operators (apply /
dismiss / select), Project-panel banner, and the sibling
multi-instance warning banner (its backend helpers already landed
on this branch) from commit a85ed6032 on gizmos-8088.

All tool.* dependencies (Geometry.reimport_element_representations,
Blender.set_objects_selection, Array.*) and IfcImporter.gross_elements
are already on this branch -- no other diffs from a85ed6032 are
pulled.

The source's narrow except-tuple paraphrase comments are trimmed
to keep only the durable "don't swallow programmer errors" note,
per CLAUDE.md s4a.

Tests: 5 bim-lane tests in test/bim/module/project/
test_pending_opening_cuts.py covering apply happy-path + missing
entity, dismiss, select happy-path + cancellation.

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/module/project/__init__.py

@@ -28,6 +28,10 @@ classes = (
     operator.AppendLibraryElementByQuery,
     operator.AssignLibraryDeclaration,
     operator.BIM_FH_import_ifc,
+    operator.BIM_OT_apply_pending_opening_cuts,
+    operator.BIM_OT_dismiss_multi_instance_warning,
+    operator.BIM_OT_dismiss_pending_opening_cuts,
+    operator.BIM_OT_select_pending_opening_cuts,
     operator.BIM_OT_load_clipping_planes,
     operator.BIM_OT_save_clipping_planes,
     operator.ChangeLibraryElement,
@@ -82,6 +86,7 @@ classes = (
     prop.FilterCategory,
     prop.Link,
     prop.EditedObj,
+    prop.PendingOpeningRecut,
     prop.BIMProjectProperties,
     prop.MeasureToolSettings,
     ui.BIM_MT_new_project,

src/bonsai/bonsai/bim/module/project/operator.py

@@ -1223,6 +1223,19 @@ class LoadProjectElements(bpy.types.Operator):
         props = tool.Project.get_project_props()
         props.is_loading = False
 
+        # Stash elements the kernel skipped opening cuts on (HasOpenings > void_limit).
+        # The Project panel banner offers the user a one-click recut.
+        props.pending_opening_recut.clear()
+        if ifc_importer.gross_elements:
+            for element in ifc_importer.gross_elements:
+                item = props.pending_opening_recut.add()
+                item.ifc_definition_id = element.id()
+            self.report(
+                {"WARNING"},
+                f"{len(ifc_importer.gross_elements)} element(s) had too many openings and were loaded without cuts. "
+                f"Apply manually from the Project panel.",
+            )
+
         tool.Project.load_default_thumbnails()
         tool.Project.set_default_context()
         tool.Project.set_default_modeling_dimensions()
@@ -3421,3 +3434,108 @@ class GenerateUVMap(bpy.types.Operator):
         tool.Loader.load_generated_uv_map(obj.data)
         self.report({"INFO"}, "Generated UV map for selected mesh.")
         return {"FINISHED"}
+
+
+class BIM_OT_apply_pending_opening_cuts(bpy.types.Operator, tool.Ifc.Operator):
+    """Recompute the wall mesh including opening subtractions for every host
+    that the load-time ``void_limit`` filter skipped. Clears the deferred
+    list on completion so the panel banner disappears."""
+
+    bl_idname = "bim.apply_pending_opening_cuts"
+    bl_label = "Apply Pending Opening Cuts"
+    bl_description = (
+        "Recompute meshes for elements whose openings were skipped at load because they had too many openings"
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context: bpy.types.Context) -> set[str]:
+        pending = tool.Project.get_project_props().pending_opening_recut
+        applied = 0
+        skipped = 0
+        failed = 0
+        for item in pending:
+            try:
+                element = tool.Ifc.get().by_id(item.ifc_definition_id)
+            except RuntimeError:
+                skipped += 1
+                continue
+            obj = tool.Ifc.get_object(element)
+            if obj is None:
+                skipped += 1
+                continue
+            body = ifcopenshell.util.representation.get_representation(element, "Model", "Body", "MODEL_VIEW")
+            if body is None:
+                skipped += 1
+                continue
+            try:
+                tool.Geometry.reimport_element_representations(obj, body, apply_openings=True)
+                applied += 1
+            except (RuntimeError, OSError, AttributeError) as exc:
+                # Programmer errors (TypeError, ValueError, etc.) must surface — don't swallow them.
+                failed += 1
+                print(f"apply_pending_opening_cuts: failed to recompute {element} ({exc})")
+
+        pending.clear()
+        message = f"Applied opening cuts to {applied} element(s)."
+        if skipped:
+            message += f" {skipped} entry/entries skipped (entity or object no longer available)."
+        if failed:
+            message += f" {failed} entry/entries failed (see system console)."
+            self.report({"WARNING"}, message)
+        else:
+            self.report({"INFO"}, message)
+        return {"FINISHED"}
+
+
+class BIM_OT_dismiss_pending_opening_cuts(bpy.types.Operator):
+    bl_idname = "bim.dismiss_pending_opening_cuts"
+    bl_label = "Dismiss Pending Opening Cuts"
+    bl_description = "Clear the pending opening-cut list without applying it. Walls stay solid where openings would have been subtracted."
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        tool.Project.get_project_props().pending_opening_recut.clear()
+        return {"FINISHED"}
+
+
+class BIM_OT_dismiss_multi_instance_warning(bpy.types.Operator):
+    bl_idname = "bim.dismiss_multi_instance_warning"
+    bl_label = "Dismiss Multi-Instance Warning"
+    bl_description = (
+        "Hide the warning that another Blender instance has this IFC file open. Sticky for the current session."
+    )
+    bl_options = {"REGISTER"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        from bonsai.bim.ifc import dismiss_multi_instance_warning
+
+        dismiss_multi_instance_warning()
+        return {"FINISHED"}
+
+
+class BIM_OT_select_pending_opening_cuts(bpy.types.Operator):
+    bl_idname = "bim.select_pending_opening_cuts"
+    bl_label = "Select Elements With Skipped Opening Cuts"
+    bl_description = "Select the Blender objects whose openings were skipped at load. Useful for locating which elements need attention."
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        ifc_file = tool.Ifc.get()
+        if ifc_file is None:
+            self.report({"INFO"}, "No IFC file loaded.")
+            return {"CANCELLED"}
+        objects: list[bpy.types.Object] = []
+        for item in tool.Project.get_project_props().pending_opening_recut:
+            try:
+                element = ifc_file.by_id(item.ifc_definition_id)
+            except RuntimeError:
+                continue
+            obj = tool.Ifc.get_object(element)
+            if obj is not None:
+                objects.append(obj)
+        if not objects:
+            self.report({"INFO"}, "No matching Blender objects found for the pending list.")
+            return {"CANCELLED"}
+        tool.Blender.set_objects_selection(context, active_object=objects[0], selected_objects=objects)
+        self.report({"INFO"}, f"Selected {len(objects)} element(s).")
+        return {"FINISHED"}

src/bonsai/bonsai/bim/module/project/prop.py

@@ -295,6 +295,17 @@ class LibraryBreadcrumb(PropertyGroup):
         library_id: int
 
 
+class PendingOpeningRecut(PropertyGroup):
+    """One element whose ``HasOpenings`` exceeded ``void_limit`` at load time
+    and was imported without opening subtractions. The user can later apply
+    them on demand from the Project panel banner."""
+
+    ifc_definition_id: IntProperty(name="IFC Definition ID")
+
+    if TYPE_CHECKING:
+        ifc_definition_id: int
+
+
 class BIMProjectProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing", default=False)
     is_loading: BoolProperty(name="Is Loading", default=False)
@@ -360,6 +371,7 @@ class BIMProjectProperties(PropertyGroup):
         default=30,
         description="Maxium number of openings that object can have. If object has more openings, it will be loaded without openings",
     )
+    pending_opening_recut: CollectionProperty(name="Pending Opening Recut", type=PendingOpeningRecut)
     style_limit: IntProperty(
         name="Style Limit",
         default=300,
@@ -525,6 +537,7 @@ class BIMProjectProperties(PropertyGroup):
         deflection_tolerance: float
         angular_tolerance: float
         void_limit: int
+        pending_opening_recut: bpy.types.bpy_prop_collection_idprop[PendingOpeningRecut]
         style_limit: int
         distance_limit: float
         false_origin_mode: Literal["AUTOMATIC", "MANUAL", "DISABLED"]

src/bonsai/bonsai/bim/module/project/ui.py

@@ -28,8 +28,9 @@ from bpy.types import Menu, Panel, UIList
 import bonsai.bim
 import bonsai.tool as tool
 from bonsai.bim.helper import draw_attributes, prop_with_search
-from bonsai.bim.ifc import IfcStore
+from bonsai.bim.ifc import IfcStore, is_cache_locked_by_other_process
 from bonsai.bim.module.project.data import LinksData, ProjectData
+from bonsai.bim.ui import draw_multiline_text
 
 if TYPE_CHECKING:
     from bonsai.bim.module.project.prop import (
@@ -166,6 +167,20 @@ class BIM_PT_project(Panel):
         if pprops.is_loading:
             self.draw_advanced_loading_ui(context)
         elif self.file or props.ifc_file:
+            if is_cache_locked_by_other_process():
+                box = self.layout.box()
+                box.alert = True
+                row = box.row(align=True)
+                row.label(text="IFC Already Open in Another Blender Instance", icon="ERROR")
+                row.operator("bim.dismiss_multi_instance_warning", text="", icon="CANCEL")
+                draw_multiline_text(
+                    box.column(align=True),
+                    "This file is open in another Blender instance. Editing the same "
+                    "IFC from two instances at once can lose your work or display "
+                    "outdated geometry. Close the other Blender instances to continue safely.",
+                    context=context,
+                )
+
             if props.has_blend_warning:
                 box = self.layout.box()
                 box.alert = True
@@ -175,6 +190,21 @@ class BIM_PT_project(Panel):
                 op.uri = "https://docs.bonsaibim.org/guides/troubleshooting.html#saving-and-loading-blend-files"
                 row.operator("bim.close_blend_warning", text="", icon="CANCEL")
 
+            if pending := pprops.pending_opening_recut:
+                box = self.layout.box()
+                box.alert = True
+                box.label(text="Opening Cuts Skipped", icon="ERROR")
+                draw_multiline_text(
+                    box.column(align=True),
+                    f"{len(pending)} element(s) had too many openings to cut during load. "
+                    f"Apply to recompute their meshes, or dismiss to leave them as they are.",
+                    context=context,
+                )
+                row = box.row(align=True)
+                row.operator("bim.select_pending_opening_cuts", text="Select Elements", icon="RESTRICT_SELECT_OFF")
+                row.operator("bim.apply_pending_opening_cuts", text="Apply Openings", icon="PLAY")
+                row.operator("bim.dismiss_pending_opening_cuts", text="", icon="CANCEL")
+
             if props.ifc_file:
                 self.draw_loaded_project_ui(context)
             else:

src/bonsai/test/bim/module/project/__init__.py

@@ -0,0 +1,19 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.

src/bonsai/test/bim/module/project/test_pending_opening_cuts.py

@@ -0,0 +1,108 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+from unittest.mock import patch
+
+import bpy
+import ifcopenshell
+import pytest
+
+import bonsai.tool as tool
+from test.bim.bootstrap import NewIfc
+
+pytestmark = pytest.mark.project
+
+
+def _populate_pending(*element_ids: int) -> None:
+    pending = tool.Project.get_project_props().pending_opening_recut
+    pending.clear()
+    for eid in element_ids:
+        pending.add().ifc_definition_id = eid
+
+
+def _make_linked_wall(name: str = "Wall") -> tuple[ifcopenshell.entity_instance, bpy.types.Object]:
+    ifc_file = tool.Ifc.get()
+    element = ifc_file.create_entity("IfcWall", GlobalId=ifcopenshell.guid.new(), Name=name)
+    obj = bpy.data.objects.new(name, bpy.data.meshes.new(name))
+    bpy.context.scene.collection.objects.link(obj)
+    tool.Ifc.link(element, obj)
+    return element, obj
+
+
+class TestApplyPendingOpeningCuts(NewIfc):
+    def test_clears_pending_and_calls_reimport_with_apply_openings(self):
+        element, obj = _make_linked_wall()
+        _populate_pending(element.id())
+
+        with patch.object(tool.Geometry, "reimport_element_representations") as mock_reimport, patch(
+            "ifcopenshell.util.representation.get_representation",
+            return_value=object(),
+        ):
+            result = bpy.ops.bim.apply_pending_opening_cuts()
+
+        assert result == {"FINISHED"}
+        assert len(tool.Project.get_project_props().pending_opening_recut) == 0
+        mock_reimport.assert_called_once()
+        _, kwargs = mock_reimport.call_args
+        assert kwargs.get("apply_openings") is True
+
+    def test_skips_entries_whose_entity_is_gone(self):
+        _populate_pending(99999)  # ID guaranteed not present
+
+        with patch.object(tool.Geometry, "reimport_element_representations") as mock_reimport:
+            result = bpy.ops.bim.apply_pending_opening_cuts()
+
+        assert result == {"FINISHED"}
+        assert len(tool.Project.get_project_props().pending_opening_recut) == 0
+        mock_reimport.assert_not_called()
+
+
+class TestDismissPendingOpeningCuts(NewIfc):
+    def test_clears_collection_without_calling_reimport(self):
+        element, _obj = _make_linked_wall()
+        _populate_pending(element.id())
+
+        with patch.object(tool.Geometry, "reimport_element_representations") as mock_reimport:
+            result = bpy.ops.bim.dismiss_pending_opening_cuts()
+
+        assert result == {"FINISHED"}
+        assert len(tool.Project.get_project_props().pending_opening_recut) == 0
+        mock_reimport.assert_not_called()
+
+
+class TestSelectPendingOpeningCuts(NewIfc):
+    def test_selects_objects_for_each_pending_entry(self):
+        e1, o1 = _make_linked_wall("WallA")
+        e2, o2 = _make_linked_wall("WallB")
+        _populate_pending(e1.id(), e2.id())
+
+        for obj in bpy.context.view_layer.objects:
+            obj.select_set(False)
+
+        result = bpy.ops.bim.select_pending_opening_cuts()
+
+        assert result == {"FINISHED"}
+        assert o1.select_get() and o2.select_get()
+        assert bpy.context.view_layer.objects.active in (o1, o2)
+
+    def test_cancels_when_no_objects_match(self):
+        _populate_pending(99999)
+        result = bpy.ops.bim.select_pending_opening_cuts()
+        assert result == {"CANCELLED"}