fix cascading schedule when parent tasks have sequence relationships #3772

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

@@ -426,3 +426,23 @@ def get_tasks_for_product(product, schedule=None):
         ]
 
     return inputs, outputs
+
+
+def get_sequence_assignment(task, sequence="successor"):
+    if sequence == "successor":
+        relationship_attr = "IsPredecessorTo"
+    elif sequence == "predecessor":
+        relationship_attr = "IsSuccessorFrom"
+    else:
+        return []
+
+    relationship = getattr(task, relationship_attr, None)
+    if relationship:
+        return relationship
+
+    for rel in task.Nests or []:
+        result = get_sequence_assignment(rel.RelatingObject, sequence)
+        if result:
+            return result
+
+    return []