fix: attach sr no si standalone credit note

erpnext/accounts/doctype/sales_invoice/sales_invoice.py

@@ -42,7 +42,11 @@ from erpnext.projects.doctype.timesheet.timesheet import get_projectwise_timeshe
 from erpnext.setup.doctype.company.company import update_company_current_month_sales
 from erpnext.stock.doctype.batch.batch import set_batch_nos
 from erpnext.stock.doctype.delivery_note.delivery_note import update_billed_amount_based_on_so
-from erpnext.stock.doctype.serial_no.serial_no import get_delivery_note_serial_no, get_serial_nos
+from erpnext.stock.doctype.serial_no.serial_no import (
+	get_delivery_note_serial_no,
+	get_serial_nos,
+	update_serial_nos_after_submit,
+)
 from erpnext.stock.utils import calculate_mapped_packed_items_return
 
 form_grid_templates = {
@@ -226,6 +230,9 @@ class SalesInvoice(SellingController):
 		# because updating reserved qty in bin depends upon updated delivered qty in SO
 		if self.update_stock == 1:
 			self.update_stock_ledger()
+		if self.is_return and self.update_stock:
+			update_serial_nos_after_submit(self, "items")
+
 
 		# this sequence because outstanding may get -ve
 		self.make_gl_entries()

erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py

@@ -2617,11 +2617,9 @@ class TestSalesInvoice(unittest.TestCase):
 
 	def test_standalone_serial_no_return(self):
 		si = create_sales_invoice(item_code="_Test Serialized Item With Series", update_stock=True, is_return=True, qty=-1)
-		si.submit()
+		si.reload()
 		self.assertTrue(si.items[0].serial_no)
 
-		return si
-
 
 def get_sales_invoice_for_e_invoice():
 	si = make_sales_invoice_for_ewaybill()

erpnext/stock/doctype/delivery_note/delivery_note.py

@@ -13,7 +13,10 @@ from frappe.utils import cint, flt
 from erpnext.controllers.accounts_controller import get_taxes_and_charges
 from erpnext.controllers.selling_controller import SellingController
 from erpnext.stock.doctype.batch.batch import set_batch_nos
-from erpnext.stock.doctype.serial_no.serial_no import get_delivery_note_serial_no
+from erpnext.stock.doctype.serial_no.serial_no import (
+	get_delivery_note_serial_no,
+	update_serial_nos_after_submit,
+)
 from erpnext.stock.utils import calculate_mapped_packed_items_return
 
 form_grid_templates = {
@@ -220,6 +223,9 @@ class DeliveryNote(SellingController):
 		# Updating stock ledger should always be called after updating prevdoc status,
 		# because updating reserved qty in bin depends upon updated delivered qty in SO
 		self.update_stock_ledger()
+		if self.is_return:
+			update_serial_nos_after_submit(self, "items")
+
 		self.make_gl_entries()
 		self.repost_future_sle_and_gle()
 

erpnext/stock/doctype/delivery_note/test_delivery_note.py

@@ -822,6 +822,11 @@ class TestDeliveryNote(FrappeTestCase):
 
 		automatically_fetch_payment_terms(enable=0)
 
+	def test_standalone_serial_no_return(self):
+		dn = create_delivery_note(item_code="_Test Serialized Item With Series", is_return=True, qty=-1)
+		dn.reload()
+		self.assertTrue(dn.items[0].serial_no)
+
 def create_return_delivery_note(**args):
 	args = frappe._dict(args)
 	from erpnext.controllers.sales_and_purchase_return import make_return_doc

erpnext/stock/doctype/serial_no/serial_no.py

@@ -394,7 +394,7 @@ def update_serial_nos(sle, item_det):
 	if not sle.is_cancelled and not sle.serial_no and cint(sle.actual_qty) > 0 \
 			and item_det.has_serial_no == 1 and item_det.serial_no_series:
 		serial_nos = get_auto_serial_nos(item_det.serial_no_series, sle.actual_qty)
-		frappe.db.set(sle, "serial_no", serial_nos)
+		sle.db_set("serial_no", serial_nos)
 		validate_serial_no(sle, item_det)
 	if sle.serial_no:
 		auto_make_serial_nos(sle)
@@ -516,13 +516,16 @@ def update_serial_nos_after_submit(controller, parentfield):
 		if controller.doctype == "Stock Entry":
 			warehouse = d.t_warehouse
 			qty = d.transfer_qty
+		elif controller.doctype in ("Sales Invoice", "Delivery Note"):
+			warehouse = d.warehouse
+			qty = d.stock_qty
 		else:
 			warehouse = d.warehouse
 			qty = (d.qty if controller.doctype == "Stock Reconciliation"
 				else d.stock_qty)
 		for sle in stock_ledger_entries:
 			if sle.voucher_detail_no==d.name:
-				if not accepted_serial_nos_updated and qty and abs(sle.actual_qty)==qty \
+				if not accepted_serial_nos_updated and qty and abs(sle.actual_qty) == abs(qty) \
 					and sle.warehouse == warehouse and sle.serial_no != d.serial_no:
 						d.serial_no = sle.serial_no
 						frappe.db.set_value(d.doctype, d.name, "serial_no", sle.serial_no)