fix: added validation for duplicate serial nos in pos

erpnext/accounts/doctype/pos_invoice/pos_invoice.py

@@ -6,7 +6,7 @@
 from frappe import _
 from frappe.query_builder.functions import IfNull, Sum
 from frappe.utils import cint, flt, get_link_to_form, getdate, nowdate
-
+import collections
 from erpnext.accounts.doctype.loyalty_program.loyalty_program import validate_loyalty_points
 from erpnext.accounts.doctype.payment_request.payment_request import make_payment_request
 from erpnext.accounts.doctype.sales_invoice.sales_invoice import (
@@ -55,6 +55,7 @@ def validate(self):
 		self.validate_payment_amount()
 		self.validate_loyalty_transaction()
 		self.validate_company_with_pos_company()
+		self.validate_duplicate_serial_and_batch_no()
 		if self.coupon_code:
 			from erpnext.accounts.doctype.pricing_rule.utils import validate_coupon_code
 
@@ -155,6 +156,27 @@ def validate_pos_reserved_serial_nos(self, item):
 				title=_("Item Unavailable"),
 			)
 
+	def validate_duplicate_serial_and_batch_no(self):
+		serial_nos = []
+		batch_nos = []
+
+		for row in self.get("items"):
+			if row.serial_no:
+				serial_nos = row.serial_no.split("\n")
+
+			if row.batch_no and not row.serial_no:
+				batch_nos.append(row.batch_no)
+
+		if serial_nos:
+			for key, value in collections.Counter(serial_nos).items():
+				if value > 1:
+					frappe.throw(_("Duplicate Serial No {0} found").format("key"))
+
+		if batch_nos:
+			for key, value in collections.Counter(batch_nos).items():
+				if value > 1:
+					frappe.throw(_("Duplicate Batch No {0} found").format("key"))
+
 	def validate_pos_reserved_batch_qty(self, item):
 		filters = {"item_code": item.item_code, "warehouse": item.warehouse, "batch_no": item.batch_no}
 

erpnext/accounts/doctype/pos_invoice/test_pos_invoice.py

@@ -464,6 +464,38 @@ def test_delivered_serialized_item_transaction(self):
 		pos2.insert()
 		self.assertRaises(frappe.ValidationError, pos2.submit)
 
+	def test_pos_invoice_with_duplicate_serial_no(self):
+		from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
+		from erpnext.stock.doctype.stock_entry.test_stock_entry import make_serialized_item
+
+		se = make_serialized_item(
+			company="_Test Company",
+			target_warehouse="Stores - _TC",
+			cost_center="Main - _TC",
+			expense_account="Cost of Goods Sold - _TC",
+		)
+
+		serial_nos = get_serial_nos(se.get("items")[0].serial_no)
+
+		pos = create_pos_invoice(
+			company="_Test Company",
+			debit_to="Debtors - _TC",
+			account_for_change_amount="Cash - _TC",
+			warehouse="Stores - _TC",
+			income_account="Sales - _TC",
+			expense_account="Cost of Goods Sold - _TC",
+			cost_center="Main - _TC",
+			item=se.get("items")[0].item_code,
+			rate=1000,
+			qty=2,
+			do_not_save=1,
+		)
+
+		pos.get("items")[0].has_serial_no = 1
+		pos.get("items")[0].serial_no = serial_nos[0] + "\n" + serial_nos[0]
+		self.assertRaises(frappe.ValidationError, pos.submit)
+
+
 	def test_invalid_serial_no_validation(self):
 		from erpnext.stock.doctype.stock_entry.test_stock_entry import make_serialized_item