Access populated_optimized on DatasetCollection, not instance.

Co-authored-by: Marius van den Beek <[email protected]>

lib/galaxy/managers/hdcas.py

@@ -41,7 +41,7 @@ def stream_dataset_collection(dataset_collection_instance, upstream_mod_zip=Fals
 
 
 def write_dataset_collection(dataset_collection_instance, archive):
-    if not dataset_collection_instance.populated_optimized():
+    if not dataset_collection_instance.collection.populated_optimized():
         raise RequestParameterInvalidException("Attempt to write dataset collection that has not been populated yet")
     names, hdas = get_hda_and_element_identifiers(dataset_collection_instance)
     for name, hda in zip(names, hdas):