Fix ifcpatch unit conversion for lists of ifc entities #6280

src/ifcopenshell-python/ifcopenshell/util/unit.py

@@ -24,6 +24,7 @@ from typing import Iterable
 from typing import Literal
 from typing import Optional
 from typing import Union
+from typing import Generator
 
 import ifcopenshell
 import ifcopenshell.ifcopenshell_wrapper as ifcopenshell_wrapper
@@ -803,9 +804,18 @@ def is_attr_type(
     return None
 
 
-def iter_element_and_attributes_per_type(
+FloatOrSequenceOfFloats = Union[float, tuple["FloatOrSequenceOfFloats", ...]]
-    ifc_file: ifcopenshell.file, attr_type_name: str
+
-) -> Iterable[tuple[ifcopenshell.entity_instance, ifcopenshell_wrapper.attribute, Any]]:
+
+def iter_element_and_attributes_per_type(ifc_file: ifcopenshell.file, attr_type_name: str) -> Generator[
+    tuple[
+        ifcopenshell.entity_instance,
+        ifcopenshell_wrapper.attribute,
+        Union[FloatOrSequenceOfFloats, ifcopenshell.entity_instance],
+    ],
+    None,
+    None,
+]:
     schema: ifcopenshell_wrapper.schema_definition = ifcopenshell_wrapper.schema_by_name(ifc_file.schema_identifier)
 
     for element in ifc_file:
@@ -826,6 +836,17 @@ def iter_element_and_attributes_per_type(
 
             if isinstance(val, ifcopenshell.entity_instance) and not val.is_a(attr_type_name):
                 continue
+            elif isinstance(val, tuple):
+                if not val:
+                    continue
+                val_ = val[0]
+                # If it's a tuple of entities, just yield the entities we need to edit.
+                if isinstance(val_, ifcopenshell.entity_instance):
+                    for val_ in val:
+                        if not val_.is_a(attr_type_name):
+                            continue
+                        yield element, attr, val_
+                    continue
 
             yield element, attr, val
 
@@ -863,9 +884,10 @@ def convert_file_length_units(ifc_file: ifcopenshell.file, target_units: str = "
 
     # Traverse all elements and their nested attributes in the file and convert them
     for element, attr, val in iter_element_and_attributes_per_type(file_patched, "IfcLengthMeasure"):
+        # NOTE: There is no risk of editing same entities twice as they're all recreated
+        # after file is reloaded as `file_patched`.
         if isinstance(val, ifcopenshell.entity_instance):
-            new_value = convert_value(val.wrappedValue)
+            val.wrappedValue = convert_value(val.wrappedValue)
-            getattr(element, attr.name()).wrappedValue = new_value
         else:
             new_value = convert_value(val)
             setattr(element, attr.name(), new_value)

src/ifcopenshell-python/test/util/test_unit.py

@@ -247,6 +247,32 @@ class TestConvertFileLengthUnits(test.bootstrap.IFC2X3):
         rectangle = builder.rectangle((100, 100))
         extrusion = builder.extrude(rectangle, 1000)
 
+        # IfcLengthMeasure entities.
+        product = ifcopenshell.api.root.create_entity(self.file, "IfcWall")
+        pset = ifcopenshell.api.pset.add_pset(self.file, product, "TestPset")
+        # Consider weird case when same entity is reused.
+        length_measure = self.file.create_entity("IfcLengthMeasure", 50.0)
+        enum_property = self.file.create_entity(
+            "IfcPropertyEnumeratedValue",
+            Name="Enum",
+            # Not entirely sure if there are real life cases when mixed typed entities used in the list
+            # but just to be safe.
+            EnumerationValues=[
+                length_measure,
+                self.file.create_entity("IfcLabel", "TEXT"),
+                self.file.create_entity("IfcLengthMeasure", 250.0),
+                length_measure,
+            ],
+        )
+        ifcopenshell.api.pset.edit_pset(
+            self.file,
+            pset,
+            properties={
+                "Length": self.file.create_entity("IfcLengthMeasure", 25.0),
+                "Enum": enum_property,
+            },
+        )
+
         ifcopenshell.api.unit.assign_unit(self.file, units=[unit])
         output = subject.convert_file_length_units(self.file, target_units="METER")
         assert subject.get_full_unit_name(subject.get_project_unit(output, "LENGTHUNIT")) == "METRE"
@@ -267,6 +293,12 @@ class TestConvertFileLengthUnits(test.bootstrap.IFC2X3):
             points = rectangle.Points.CoordList
         assert np.allclose(points, expected_points)
 
+        # IfcLengthMeasure entities.
+        product = output.by_type("IfcWall")[0]
+        pset_data = ifcopenshell.util.element.get_pset(product, "TestPset")
+        assert pset_data["Length"] == 0.025
+        assert pset_data["Enum"] == [0.05, "TEXT", 0.25, 0.05]
+
     def test_converting_map_conversion_if_there_is_no_map_unit(self):
         ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcProject")
         unit = ifcopenshell.api.unit.add_si_unit(self.file, unit_type="LENGTHUNIT", prefix="MILLI")