fix: Ignore PO on So cancel

erpnext/controllers/accounts_controller.py

@@ -823,7 +823,7 @@ class AccountsController(TransactionBase):
 		for item in self.items:
 			so_items.append(item.name)
 
-		linked_po = frappe.get_all(
+		linked_po = list(set(frappe.get_all(
 			'Purchase Order Item',
 			filters = {
 				'sales_order': self.name,
@@ -831,7 +831,7 @@ class AccountsController(TransactionBase):
 				'docstatus': ['<', 2]
 			},
 			pluck='parent'
-		)
+		)))
 
 		if linked_po:
 			frappe.db.set_value(

erpnext/selling/doctype/sales_order/sales_order.js

@@ -78,6 +78,8 @@ frappe.ui.form.on("Sales Order", {
 		});
 
 		erpnext.queries.setup_warehouse_query(frm);
+
+		frm.ignore_doctypes_on_cancel_all = ['Purchase Order'];
 	},
 
 	delivery_date: function(frm) {