Fix add_boolean removing second operands from unrelated representations

add_boolean was removing second operands from ALL IfcShapeRepresentations
that referenced them, which could corrupt unrelated shapes and leave
representations with empty Items (bug #7803).

The API no longer modifies Items — callers manage this explicitly.
validate_type and Bonsai's AddBoolean operator now handle their own
item removal scoped to the correct representation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -540,6 +540,16 @@ class AddBoolean(Operator, tool.Ifc.Operator):
         booleans = ifcopenshell.api.geometry.add_boolean(tool.Ifc.get(), first_item, second_items, props.operator)
 
         rep_obj = tool.Geometry.get_geometry_props().representation_obj
+        if booleans:
+            # Users typically select two top-level items and expect the
+            # operand to be absorbed into the boolean, not remain as a
+            # standalone item alongside it.
+            representation = tool.Geometry.get_active_representation(rep_obj)
+            representation = ifcopenshell.util.representation.resolve_representation(representation)
+            second_items_set = set(second_items)
+            new_items = [i for i in representation.Items if i not in second_items_set]
+            if new_items:
+                representation.Items = new_items
         rep_element = tool.Ifc.get_entity(rep_obj)
         tool.Model.mark_manual_booleans(rep_element, booleans)
         tool.Geometry.reload_representation(rep_obj)

src/ifcopenshell-python/ifcopenshell/api/geometry/add_boolean.py

@@ -31,17 +31,6 @@ def add_boolean(
 ) -> list[ifcopenshell.entity_instance]:
     """Adds a boolean operation to two or more representation items
 
-    If an IfcBooleanOperand is part of the top level items in an
-    IfcShapeRepresentation, it will be removed from that level whilst being
-    added to the IfcBooleanResult. This is because it is generally intuitive
-    that an item is either participating in a boolean operation, or being an
-    item in its own right, but not both.
-
-    However, if an IfcBooleanOperand is part of another boolean operation
-    already, it will not be removed from the existing operation. A new
-    operation will be created, and therefore it will participate in two
-    operations.
-
     This function protects against recursive booleans.
 
     After a boolean operation is made, since the items of
@@ -101,9 +90,6 @@ def add_boolean(
 
     booleans = []
     for second_item in second_items:
-        for inverse in file.get_inverse(second_item):
-            if inverse.is_a("IfcShapeRepresentation"):
-                inverse.Items = list(set(inverse.Items) - {second_item})
         if first.is_a("IfcTesselatedFaceSet"):
             first.Closed = True  # For now, trust the user to do the right thing.
         if second_item.is_a("IfcTesselatedFaceSet"):

src/ifcopenshell-python/ifcopenshell/api/geometry/validate_type.py

@@ -83,6 +83,7 @@ def validate_type(
 
     if remaining_items:
         ifcopenshell.api.geometry.add_boolean(file, preferred_item, remaining_items, "UNION")
+        representation.Items = [i for i in representation.Items if i not in remaining_items]
 
     representation.RepresentationType = ifcopenshell.util.representation.guess_type(representation.Items)
     if representation.RepresentationType == "CSG":

src/ifcopenshell-python/test/api/geometry/test_add_boolean.py

@@ -42,7 +42,7 @@ class TestAddBoolean(test.bootstrap.IFC4):
         assert boolean.FirstOperand == first
         assert boolean.SecondOperand == second
         assert boolean.Operator == "DIFFERENCE"
-        assert set(rep.Items) == {boolean}
+        assert set(rep.Items) == {boolean, second}
 
     def test_adding_multiple_booleans_from_three_top_level_items(self):
         ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
@@ -58,13 +58,14 @@ class TestAddBoolean(test.bootstrap.IFC4):
 
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second1, second2])
         assert len(booleans) == 2
-        assert len(rep.Items) == 1
-        assert rep.Items[0].FirstOperand.is_a("IfcBooleanResult")
-        assert rep.Items[0].SecondOperand == second2
-        assert rep.Items[0].Operator == "DIFFERENCE"
-        assert rep.Items[0].FirstOperand.FirstOperand == first
-        assert rep.Items[0].FirstOperand.SecondOperand == second1
-        assert rep.Items[0].FirstOperand.Operator == "DIFFERENCE"
+        final_boolean = booleans[-1]
+        assert final_boolean.FirstOperand.is_a("IfcBooleanResult")
+        assert final_boolean.SecondOperand == second2
+        assert final_boolean.Operator == "DIFFERENCE"
+        assert final_boolean.FirstOperand.FirstOperand == first
+        assert final_boolean.FirstOperand.SecondOperand == second1
+        assert final_boolean.FirstOperand.Operator == "DIFFERENCE"
+        assert set(rep.Items) == {final_boolean, second1, second2}
 
     def test_adding_a_boolean_to_an_existing_operand_from_a_top_level_item(self):
         ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
@@ -78,14 +79,16 @@ class TestAddBoolean(test.bootstrap.IFC4):
         second2 = builder.block()
         rep = builder.get_representation(body, [first, second1])
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second1])
+        # second1 stays in Items, add second2 as well
         rep.Items = list(rep.Items) + [second2]
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second2])
         assert len(booleans) == 1
-        assert len(rep.Items) == 1
-        assert rep.Items[0].FirstOperand.is_a("IfcBooleanResult")
-        assert rep.Items[0].SecondOperand == second2
-        assert rep.Items[0].FirstOperand.FirstOperand == first
-        assert rep.Items[0].FirstOperand.SecondOperand == second1
+        final_boolean = booleans[0]
+        assert final_boolean.FirstOperand.is_a("IfcBooleanResult")
+        assert final_boolean.SecondOperand == second2
+        assert final_boolean.FirstOperand.FirstOperand == first
+        assert final_boolean.FirstOperand.SecondOperand == second1
+        assert set(rep.Items) == {final_boolean, second1, second2}
 
     def test_adding_a_boolean_to_an_existing_operand_from_another_operand(self):
         ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
@@ -104,7 +107,7 @@ class TestAddBoolean(test.bootstrap.IFC4):
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first1, [second2])
 
         assert len(booleans) == 1
-        assert len(rep.Items) == 2
+        assert len(rep.Items) == 4
 
         assert self.file.get_total_inverses(first1) == 1
         result = next(iter(self.file.get_inverse(first1)))
@@ -132,14 +135,15 @@ class TestAddBoolean(test.bootstrap.IFC4):
         rep = builder.get_representation(body, [first, second])
         ifcopenshell.api.geometry.add_boolean(self.file, first, [second])
         ifcopenshell.api.geometry.add_boolean(self.file, first, [second])
-        assert len(rep.Items) == 1
-        assert rep.Items[0].FirstOperand == first
-        assert rep.Items[0].SecondOperand == second
+        assert set(rep.Items) == {self.file.by_type("IfcBooleanResult")[0], second}
+        boolean = self.file.by_type("IfcBooleanResult")[0]
+        assert boolean.FirstOperand == first
+        assert boolean.SecondOperand == second
         ifcopenshell.api.geometry.add_boolean(self.file, second, [second])
         ifcopenshell.api.geometry.add_boolean(self.file, second, [first])
-        assert len(rep.Items) == 1
-        assert rep.Items[0].FirstOperand == first
-        assert rep.Items[0].SecondOperand == second
+        assert set(rep.Items) == {boolean, second}
+        assert boolean.FirstOperand == first
+        assert boolean.SecondOperand == second
         assert len(self.file.by_type("IfcBooleanResult")) == 1
 
 

src/ifcopenshell-python/test/api/geometry/test_validate_type.py

@@ -76,7 +76,7 @@ class TestValidateType(test.bootstrap.IFC4):
 
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second1])
         assert len(booleans) == 1
-        assert len(rep.Items) == 3
+        assert len(rep.Items) == 4
         assert ifcopenshell.api.geometry.validate_type(self.file, rep) is True
         assert len(rep.Items) == 1
         assert rep.RepresentationType == "CSG"
@@ -96,9 +96,9 @@ class TestValidateType(test.bootstrap.IFC4):
 
         booleans = ifcopenshell.api.geometry.add_boolean(self.file, first, [second1])
         assert len(booleans) == 1
-        assert len(rep.Items) == 2
+        assert len(rep.Items) == 3  # boolean replaced first, but second1 stays in Items
         assert ifcopenshell.api.geometry.validate_type(self.file, rep) is False
-        assert len(rep.Items) == 2
+        assert len(rep.Items) == 2  # validate_type unioned second1 into the boolean
         assert rep.RepresentationType is None