Merge pull request #19853 from rohitwaghchaure/fixed_production_plan_items_required_to_pull_mr

fix: 'NoneType' object is not iterable
diff --git a/erpnext/manufacturing/doctype/production_plan/production_plan.py b/erpnext/manufacturing/doctype/production_plan/production_plan.py
index 25c385f..8876253 100644
--- a/erpnext/manufacturing/doctype/production_plan/production_plan.py
+++ b/erpnext/manufacturing/doctype/production_plan/production_plan.py
@@ -615,6 +615,9 @@
 
 	doc['mr_items'] = []
 	po_items = doc.get('po_items') if doc.get('po_items') else doc.get('items')
+	if not po_items:
+		frappe.throw(_("Items are required to pull the raw materials which is associated with it."))
+
 	company = doc.get('company')
 	warehouse = doc.get('for_warehouse')