fix: Party validation for inter-warehouse transaction
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index 57dc179..8b5d4d1 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -1450,11 +1450,17 @@
 		parties = frappe.db.get_all("Supplier", fields=["name"], filters={"disabled": 0, "is_internal_supplier": 1, "represents_company": doc.company})
 		company = frappe.get_cached_value("Customer", doc.customer, "represents_company")
 
+		if not parties:
+			frappe.throw(_('No Supplier found for Inter Company Transactions which represents company {0}').format(frappe.bold(doc.company)))
+
 		party = get_internal_party(parties, "Supplier", doc)
 	else:
 		parties = frappe.db.get_all("Customer", fields=["name"], filters={"disabled": 0, "is_internal_customer": 1, "represents_company": doc.company})
 		company = frappe.get_cached_value("Supplier", doc.supplier, "represents_company")
 
+		if not parties:
+			frappe.throw(_('No Customer found for Inter Company Transactions which represents company {0}').format(frappe.bold(doc.company)))
+
 		party = get_internal_party(parties, "Customer", doc)
 
 	return {