fix: serial no with zero quantity issue in stock reco

(cherry picked from commit 17131e5)

erpnext/stock/doctype/stock_reconciliation/stock_reconciliation.py

@@ -4,7 +4,7 @@
 from typing import Optional
 
 import frappe
-from frappe import _, msgprint
+from frappe import _, bold, msgprint
 from frappe.utils import cint, cstr, flt
 
 import erpnext
@@ -89,7 +89,7 @@ def _changed(item):
 
 				if item_dict.get("serial_nos"):
 					item.current_serial_no = item_dict.get("serial_nos")
-					if self.purpose == "Stock Reconciliation" and not item.serial_no:
+					if self.purpose == "Stock Reconciliation" and not item.serial_no and item.qty:
 						item.serial_no = item.current_serial_no
 
 				item.current_qty = item_dict.get("qty")
@@ -140,6 +140,14 @@ def _get_msg(row_num, msg):
 
 			self.validate_item(row.item_code, row)
 
+			if row.serial_no and not row.qty:
+				self.validation_messages.append(
+					_get_msg(
+						row_num,
+						f"Quantity should not be zero for the {bold(row.item_code)} since serial nos are specified",
+					)
+				)
+
 			# validate warehouse
 			if not frappe.db.get_value("Warehouse", row.warehouse):
 				self.validation_messages.append(_get_msg(row_num, _("Warehouse not found in the system")))