#1531 Breadth-first search and maintain insertion order on remove_deep()

src/ifcopenshell-python/ifcopenshell/file.py

@@ -359,19 +359,27 @@ class file(object):
             return [entity_instance(e, self) for e in self.wrapped_data.by_type(type)]
         return [entity_instance(e, self) for e in self.wrapped_data.by_type_excl_subtypes(type)]
 
-    def traverse(self, inst, max_levels=None):
+    def traverse(self, inst, max_levels=None, breadth_first=False):
         """Get a list of all referenced instances for a particular instance including itself
 
         :param inst: The entity instance to get all sub instances
         :type inst: ifcopenshell.entity_instance.entity_instance
         :param max_levels: How far deep to recursively fetch sub instances. None or -1 means infinite.
         :type max_levels: None|int
+        :param breadth_first: Whether to use breadth-first search, the default is depth-first.
+        :type max_levels: bool
         :returns: A list of ifcopenshell.entity_instance.entity_instance objects
         :rtype: list
         """
         if max_levels is None:
             max_levels = -1
-        return [entity_instance(e, self) for e in self.wrapped_data.traverse(inst.wrapped_data, max_levels)]
+        
+        if breadth_first:
+            fn = self.wrapped_data.traverse_breadth_first
+        else:
+            fn = self.wrapped_data.traverse
+        
+        return [entity_instance(e, self) for e in fn(inst.wrapped_data, max_levels)]
 
     def get_inverse(self, inst):
         """Return a list of entities that reference this entity

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

@@ -104,7 +104,7 @@ def has_element_reference(value, element):
 def remove_deep(ifc_file, element):
     # @todo maybe some sort of try-finally mechanism.
     ifc_file.batch()
-    subgraph = list(ifc_file.traverse(element))
+    subgraph = list(ifc_file.traverse(element, breadth_first=True))
     subgraph_set = set(subgraph)
     for ref in subgraph[::-1]:
         if ref.id() and len(set(ifc_file.get_inverse(ref)) - subgraph_set) == 0: