Property transfer ownership of schema from py to c++ upon register_schema()

src/ifcopenshell-python/ifcopenshell/__init__.py

@@ -160,9 +160,6 @@ def create_entity(type, schema="IFC4", *args, **kwargs):
     return e
 
 
-gcroot = []
-
-
 def register_schema(schema):
     """Registers a custom IFC schema
 
@@ -177,7 +174,8 @@ def register_schema(schema):
         ifcopenshell.register_schema(schema)
         ifcopenshell.file(schema="IFC_CUSTOM")
     """
-    gcroot.append(schema)
+    schema.schema.this.disown()
+    schema.disown()
     ifcopenshell_wrapper.register_schema(schema.schema)
     register_schema_attributes(schema.schema)
 

src/ifcopenshell-python/ifcopenshell/express/schema_class.py

@@ -84,7 +84,7 @@ class LateBoundSchemaInstantiator:
         for attr_name, decl_type, optional in attribute_definitions:
             attributes.append(w.attribute(attr_name, decl_type, optional))
         self.declarations[str(name)].set_attributes(attributes, is_derived)
-        self.cache.append(attributes)
+        self.cache.extend(attributes)
 
     def inverse_attributes(self, name, inv_attrs):
         attributes = []
@@ -100,6 +100,7 @@ class LateBoundSchemaInstantiator:
                     en.attributes()[attribute_entity_index],
                 )
             )
+        self.cache.extend(attributes)
         self.declarations[str(name)].set_inverse_attributes(attributes)
 
     def entity_subtypes(self, name, tys):
@@ -110,6 +111,10 @@ class LateBoundSchemaInstantiator:
             override_schema_name or self.schema_name, list(self.declarations.values()), None
         )
 
+    def disown(self):
+        for elem in self.cache + list(self.declarations.values()):
+            elem.this.disown()
+
 
 class EarlyBoundCodeWriter:
     def __init__(self, schema_name):