Fix #7208. Merge duplicates patch recipe can now control merging by empty attributes.

Moult · Moult · commit 25dacc8fed1a · 2025-10-06T23:18:32.000+11:00
diff --git a/src/ifcpatch/ifcpatch/recipes/MergeDuplicateTypes.py b/src/ifcpatch/ifcpatch/recipes/MergeDuplicateTypes.py
@@ -25,7 +25,7 @@
 
 
 class Patcher:
-    def __init__(self, file: ifcopenshell.file, logger: Logger, attribute: str = "Tag"):
+    def __init__(self, file: ifcopenshell.file, logger: Logger, attribute: str = "Tag", should_merge_null: bool = True):
         """Merge duplicate element types via the Tag or another attribute
 
         Revit is notorious for creating many duplicate element types. Element
@@ -50,6 +50,8 @@ def __init__(self, file: ifcopenshell.file, logger: Logger, attribute: str = "Ta
         :param attribute: The name of the attribute to merge element types based
             on. Typically this will be "Tag" as it stores the unique ID from the
             proprietary BIM software.
+        :param should_merge_null: If True, all elements with an empty attribute
+            will be merged. If False, they will be kept separate.
 
         Example:
 
@@ -64,12 +66,15 @@ def __init__(self, file: ifcopenshell.file, logger: Logger, attribute: str = "Ta
         self.file = file
         self.logger = logger
         self.attribute = attribute
+        self.should_merge_null = should_merge_null
 
     def patch(self):
-        key = self.attribute
         keys: dict[Any, ifcopenshell.entity_instance] = {}
         for element_type in self.file.by_type("IfcTypeObject"):
-            original_type = keys.get(getattr(element_type, key), None)
+            key = getattr(element_type, self.attribute)
+            if not key and not self.should_merge_null:
+                continue
+            original_type = keys.get(key, None)
             if original_type:
                 elements = ifcopenshell.util.element.get_types(element_type)
                 if elements:
@@ -78,7 +83,7 @@ def patch(self):
                     ifcopenshell.util.element.replace_attribute(inverse, element_type, original_type)
                 self.file.remove(element_type)
             else:
-                keys[getattr(element_type, key)] = element_type
+                keys[key] = element_type
 
     def assign_type(
         self, related_objects: list[ifcopenshell.entity_instance], relating_type: ifcopenshell.entity_instance
diff --git a/src/ifcpatch/test/test_MergeDuplicateTypes.py b/src/ifcpatch/test/test_MergeDuplicateTypes.py
@@ -74,6 +74,15 @@ def test_run(self):
         assert ifcopenshell.util.element.get_material(wall1, should_inherit=False) == None
         assert ifcopenshell.util.element.get_material(wall2, should_inherit=False) == None
 
+    def test_not_merging_empty_attributes(self):
+        wall_type1 = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWallType", name="")
+        wall_type2 = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWallType", name="")
+        output = ifcpatch.execute({"file": self.file, "recipe": "MergeDuplicateTypes", "arguments": ["Name", True]})
+        assert len(output.by_type("IfcWallType")) == 1
+        wall_type3 = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWallType", name="")
+        output = ifcpatch.execute({"file": self.file, "recipe": "MergeDuplicateTypes", "arguments": ["Name", False]})
+        assert len(output.by_type("IfcWallType")) == 2
+
 
 class TestMergeDuplicateTypesIFC2X3(test.bootstrap.IFC2X3, TestMergeDuplicateTypes):
     pass
