fix: migration; make it resilient against old, non-conforming data

erpnext/patches/v15_0/migrate_old_item_wise_tax_detail_data_format.py

@@ -26,7 +26,17 @@ def execute():
 			updated_tax_details = {}
 			needs_update = False
 
-			for item, tax_data in json.loads(doc.item_wise_tax_detail).items():
+			try:
+				item_iterator = json.loads(doc.item_wise_tax_detail).items()
+			except AttributeError as e:
+				# This is stale data from 2009 found in a database
+				if json.loads(doc.item_wise_tax_detail) == 1:
+					# meaning: replace with an empty {}
+					needs_update = True
+				else:
+					raise e
+			else:
+				for item, tax_data in item_iterator:
 					if isinstance(tax_data, list) and len(tax_data) == 2:
 						updated_tax_details[item] = ItemWiseTaxDetail(
 							tax_rate=tax_data[0],