Fix wall edit lifecycle + drain wall_offset_gizmos cache on load

Bundled bug fixes + the forward-compat AST guard that prevents the
underlying class of bug from coming back.

* bim/module/model/wall.py: FinishEditingWall._execute early-returns
  CANCELLED when props.is_editing is False. Without this guard, a
  failed enable (e.g. on a wall without IfcMaterialLayerSetUsage)
  leaves is_editing False but a press on finish still walked the
  sub-ops below, which dereferenced layer-set-dependent state and
  crashed.

* tool/model.py: Model.offset_wall now guards against
  ifcopenshell.util.element.get_material returning None before
  calling .is_a("IfcMaterialLayerSetUsage"). Fixes the pre-existing
  test/bim/module/model/test_wall_header_refresh.py crash that has
  been the only failing test in the wall lane since this branch
  started.

* bim/handler.py: _apply_save_file_invariants drains
  wall_offset_gizmos.clear_caches() on load_post. The module-scope
  GenerationKeyedCache instance survives the .blend reload; without
  the drain the cache may serve entries whose bpy_struct references
  point into the freed bpy.data of the previous file.

* test/bim/test_handler_forward_compat.py: AST-walk test that
  enumerates every bim/module/model/*.py source declaring both a
  module-scope GenerationKeyedCache assignment AND a top-level
  clear_caches function, and asserts each module appears as a
  <module>.clear_caches() call in _apply_save_file_invariants. Pins
  the contract: any future module-scope geom cache that exposes
  clear_caches must wire into the load_post drain.

* test/bim/feature/model.feature + test/bim/test_feature.py: wall
  edit-lifecycle scenarios switch from "add cube + assign as
  IfcWallType" to "load the demo construction library + add an
  occurrence of the WAL100 wall type", so the parametric edit runs
  against a real LAYER2 wall with IfcMaterialLayerSetUsage rather
  than a vanilla-mesh promotion that lacks one. The demo-library
  step also picks the schema-matching library file (IFC2X3 /
  IFC4 / IFC4X3) so the appended types remain valid across schemas.
  Door saved-height assertion updates from 2.5 → 2500 to reflect
  that BBIM_Door pset stores project units (METRIC_MM in the
  empty-project fixture).

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/handler.py

@@ -41,6 +41,7 @@ from bonsai.bim.decorator_cache import (
 from bonsai.bim.ifc import IfcStore, get_cache_or_detect_lock
 from bonsai.bim.module.aggregate.decorator import AggregateDecorator
 from bonsai.bim.module.georeference.decorator import GeoreferenceDecorator
+from bonsai.bim.module.model import wall_offset_gizmos
 from bonsai.bim.module.model.data import AuthoringData
 from bonsai.bim.module.model.decorator import (
     ArrayPreviewDecorator,
@@ -447,6 +448,7 @@ def _apply_save_file_invariants(scene: bpy.types.Scene) -> None:
 
     tool.Parametric.heal_stale_edit_flags()
     discard_pending_previews(scene)
+    wall_offset_gizmos.clear_caches()
 
     if tool.Ifc.get() and bpy.data.is_saved:
         props = tool.Blender.get_bim_props()

src/bonsai/bonsai/bim/module/model/wall.py

@@ -1821,6 +1821,12 @@ class FinishEditingWall(bpy.types.Operator, tool.Ifc.Operator):
         if not element:
             return {"CANCELLED"}
         props = tool.Model.get_wall_props(obj)
+        # No edit session in progress — finish is a true no-op. Without this guard,
+        # an enable that failed validation (e.g. wall without IfcMaterialLayerSetUsage)
+        # leaves is_editing=False but a press on finish still walks the sub-ops below,
+        # which dereference layer-set-dependent state and crash.
+        if not props.is_editing:
+            return {"CANCELLED"}
 
         length_changed = not tool.Cad.is_x(props.length, props.snap_length, tolerance=1e-5)
         height_changed = not tool.Cad.is_x(props.height, props.snap_height, tolerance=1e-5)

src/bonsai/bonsai/tool/model.py

@@ -2943,7 +2943,7 @@ class Model(bonsai.core.tool.Model):
     def offset_wall(cls, wall: bpy.types.Object, baseline: Literal["EXTERIOR", "INTERIOR", "CENTER"]) -> None:
         element = tool.Ifc.get_entity(wall)
         usage = ifcopenshell.util.element.get_material(element)
-        if not usage.is_a("IfcMaterialLayerSetUsage"):
+        if usage is None or not usage.is_a("IfcMaterialLayerSetUsage"):
             return
         layer_set = usage.ForLayerSet
         if baseline == "CENTER":

src/bonsai/test/bim/feature/model.feature

@@ -687,8 +687,10 @@ Scenario: Saving with a door mid-edit auto-commits the draft value to the IFC ps
     Then "active_object.BIMDoorProperties.is_editing" is "True"
     When I press "bim.save_project(filepath='{temp_project_path}', should_save_as=True)"
     Then "active_object.BIMDoorProperties.is_editing" is "False"
+    # BBIM_<Type> psets store project units, not raw Blender SI. The empty project
+    # used in an_empty_blender_session is METRIC_MM, so 2.5 m → 2500 mm in the pset.
     And the variable "saved_height" is "__import__('json').loads(ifcopenshell.util.element.get_pset({ifc}.by_type('IfcDoor')[0], 'BBIM_Door', 'Data'))['overall_height']"
-    And the variable "saved_height" equals "2.5"
+    And the variable "saved_height" equals "2500.0"
 
 Scenario: Saving with no parametric edits in progress leaves the door pset unchanged
     Given an empty IFC project
@@ -705,14 +707,10 @@ Scenario: Saving with no parametric edits in progress leaves the door pset uncha
 
 Scenario: Saving with a wall mid-edit auto-commits the draft to IFC
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWallType"
-    And I press "bim.assign_class"
+    And I load the demo construction library
     And I set "scene.BIMModelProperties.ifc_class" to "IfcWallType"
-    And the variable "cube" is "{ifc}.by_type('IfcWallType')[0].id()"
-    And I set "scene.BIMModelProperties.relating_type_id" to "{cube}"
+    And the variable "element_type" is "[e for e in {ifc}.by_type('IfcWallType') if e.Name == 'WAL100'][0].id()"
+    And I set "scene.BIMModelProperties.relating_type_id" to "{element_type}"
     And I press "bim.add_occurrence"
     And the object "IfcWall/Wall" is selected
     And I press "bim.enable_editing_wall()"
@@ -722,21 +720,18 @@ Scenario: Saving with a wall mid-edit auto-commits the draft to IFC
 
 Scenario: Enabling and finishing a wall edit with no drag is a no-op
     Given an empty IFC project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWallType"
-    And I press "bim.assign_class"
+    And I load the demo construction library
     And I set "scene.BIMModelProperties.ifc_class" to "IfcWallType"
-    And the variable "cube" is "{ifc}.by_type('IfcWallType')[0].id()"
-    And I set "scene.BIMModelProperties.relating_type_id" to "{cube}"
+    And the variable "element_type" is "[e for e in {ifc}.by_type('IfcWallType') if e.Name == 'WAL100'][0].id()"
+    And I set "scene.BIMModelProperties.relating_type_id" to "{element_type}"
     And I press "bim.add_occurrence"
     And the object "IfcWall/Wall" is selected
     And the variable "entity_count_before" is "len(list({ifc}))"
     When I press "bim.enable_editing_wall()"
     And I press "bim.finish_editing_wall()"
     Then "active_object.BIMWallProperties.is_editing" is "False"
-    And "len(list({ifc}))" is "{entity_count_before}"
+    And the variable "entity_count_after" is "len(list({ifc}))"
+    And the variable "entity_count_after" equals "{entity_count_before}"
 
 Scenario: Cancelling a wall edit clears is_editing
     Given an empty IFC project
@@ -756,14 +751,10 @@ Scenario: Cancelling a wall edit clears is_editing
 
 Scenario: Wall parametric edit works on IFC2X3 projects
     Given an empty IFC2X3 project
-    And I add a cube
-    And the object "Cube" is selected
-    And I set "scene.BIMRootProperties.ifc_product" to "IfcElementType"
-    And I set "scene.BIMRootProperties.ifc_class" to "IfcWallType"
-    And I press "bim.assign_class"
+    And I load the demo construction library
     And I set "scene.BIMModelProperties.ifc_class" to "IfcWallType"
-    And the variable "cube" is "{ifc}.by_type('IfcWallType')[0].id()"
-    And I set "scene.BIMModelProperties.relating_type_id" to "{cube}"
+    And the variable "element_type" is "[e for e in {ifc}.by_type('IfcWallType') if e.Name == 'WAL100'][0].id()"
+    And I set "scene.BIMModelProperties.relating_type_id" to "{element_type}"
     And I press "bim.add_occurrence"
     And the object "IfcWall/Wall" is selected
     When I press "bim.enable_editing_wall()"

src/bonsai/test/bim/test_feature.py

@@ -1764,7 +1764,17 @@ def i_load_the_ifc_test_file(filepath):
 @given("I load the demo construction library")
 @when("I load the demo construction library")
 def i_add_a_construction_library():
-    lib_path = "./bonsai/bim/data/libraries/IFC4 Demo Library.ifc"
+    # Pick the library file whose schema matches the current project so the
+    # appended types are valid (IFC2X3-vs-IFC4 entity attributes differ).
+    schema_to_library = {
+        "IFC2X3": "IFC2X3 Demo Library.ifc",
+        "IFC4": "IFC4 Demo Library.ifc",
+        "IFC4X3": "IFC4X3 Demo Library.ifc",
+        "IFC4X3_ADD2": "IFC4X3 Demo Library.ifc",
+    }
+    schema = tool.Ifc.get().schema
+    lib_name = schema_to_library.get(schema, "IFC4 Demo Library.ifc")
+    lib_path = f"./bonsai/bim/data/libraries/{lib_name}"
     bpy.ops.bim.select_library_file(filepath=lib_path, append_all=True)
 
 

src/bonsai/test/bim/test_handler_forward_compat.py

@@ -35,6 +35,7 @@ pytestmark = pytest.mark.model
 
 HANDLER_PATH = Path(__file__).parent.parent.parent / "bonsai" / "bim" / "handler.py"
 PARAMETRIC_PATH = HANDLER_PATH.parent.parent / "tool" / "parametric.py"
+MODEL_MODULE_DIR = HANDLER_PATH.parent / "module" / "model"
 
 # User-intent enums encode the user's "what to build next" choice on the
 # BIM Tool panel. The header-only writer must never drift into enum writes;
@@ -117,3 +118,59 @@ def test_refresh_post_commit_gates_header_refresh_on_edit_types_registry() -> No
         "fires the refresh for commits in contexts that strip view-layer attributes; "
         "a missing call silently drops the validate-gizmo header refresh."
     )
+
+
+def _modules_with_module_scope_cache_and_clear():
+    """Yield ``module_name`` for every ``bim/module/model/*.py`` source that
+    declares a module-scope ``GenerationKeyedCache()`` assignment AND a
+    top-level ``def clear_caches``. These are the modules whose cache state
+    survives file loads and must be drained from ``_apply_save_file_invariants``."""
+    for path in MODEL_MODULE_DIR.glob("*.py"):
+        tree = ast.parse(path.read_text(encoding="utf-8"))
+        has_cache = False
+        has_clear = False
+        for node in tree.body:
+            if isinstance(node, ast.FunctionDef) and node.name == "clear_caches":
+                has_clear = True
+                continue
+            if isinstance(node, ast.Assign):
+                for sub in ast.walk(node.value):
+                    if (
+                        isinstance(sub, ast.Call)
+                        and isinstance(sub.func, ast.Attribute)
+                        and sub.func.attr == "GenerationKeyedCache"
+                    ):
+                        has_cache = True
+                        break
+        if has_cache and has_clear:
+            yield path.stem
+
+
+def test_apply_save_file_invariants_drains_every_module_scope_geom_cache(handler_tree: ast.Module) -> None:
+    """Module-scope ``GenerationKeyedCache`` instances persist across file
+    loads — the counter they invalidate against is class-level and survives
+    a ``.blend`` reload. Without a ``load_post`` drain the cache may serve
+    entries whose ``bpy_struct`` references point into the previous file's
+    freed ``bpy.data``, raising ``ReferenceError`` on the next attribute read.
+
+    Pin: every model module that exposes both a module-scope cache and a
+    top-level ``clear_caches`` is called from ``_apply_save_file_invariants``,
+    the central post-load drain."""
+    fn = _function_node(handler_tree, "_apply_save_file_invariants")
+    drained: set[str] = set()
+    for node in ast.walk(fn):
+        if (
+            isinstance(node, ast.Call)
+            and isinstance(node.func, ast.Attribute)
+            and node.func.attr == "clear_caches"
+            and isinstance(node.func.value, ast.Name)
+        ):
+            drained.add(node.func.value.id)
+    missing = [name for name in _modules_with_module_scope_cache_and_clear() if name not in drained]
+    if missing:
+        pytest.fail(
+            "Module(s) expose a module-scope GenerationKeyedCache + clear_caches() but "
+            f"_apply_save_file_invariants does not drain them on load_post: {sorted(missing)}. "
+            "Add a `<module>.clear_caches()` call so freshly-loaded files cannot serve "
+            "entries holding freed bpy.data references from the previous file."
+        )