fix: get default stock uom (#45384)

Co-authored-by: Sagar Vora <sagar@resilient.tech>

erpnext/accounts/doctype/opening_invoice_creation_tool/opening_invoice_creation_tool.py

@@ -11,6 +11,7 @@ from frappe.utils.background_jobs import enqueue, is_job_enqueued
 from erpnext.accounts.doctype.accounting_dimension.accounting_dimension import (
 	get_accounting_dimensions,
 )
+from erpnext.stock.utils import get_default_stock_uom
 
 
 class OpeningInvoiceCreationTool(Document):
@@ -172,7 +173,7 @@ class OpeningInvoiceCreationTool(Document):
 			income_expense_account_field = (
 				"income_account" if row.party_type == "Customer" else "expense_account"
 			)
-			default_uom = frappe.db.get_single_value("Stock Settings", "stock_uom") or "Nos"
+			default_uom = get_default_stock_uom()
 			rate = flt(row.outstanding_amount) / flt(row.qty)
 
 			item_dict = frappe._dict(

erpnext/regional/italy/utils.py

@@ -8,6 +8,7 @@ from frappe.utils.file_manager import remove_file
 
 from erpnext.controllers.taxes_and_totals import ItemWiseTaxDetail, get_itemised_tax
 from erpnext.regional.italy import state_codes
+from erpnext.stock.utils import get_default_stock_uom
 
 
 def update_itemised_tax_data(doc):
@@ -159,7 +160,7 @@ def get_invoice_summary(items, taxes):
 						rate=reference_row.tax_amount,
 						qty=1.0,
 						amount=reference_row.tax_amount,
-						stock_uom=frappe.db.get_single_value("Stock Settings", "stock_uom") or "Nos",
+						stock_uom=get_default_stock_uom(),
 						tax_rate=tax.rate,
 						tax_amount=(reference_row.tax_amount * tax.rate) / 100,
 						net_amount=reference_row.tax_amount,

erpnext/stock/utils.py

@@ -658,3 +658,26 @@ def get_combine_datetime(posting_date, posting_time):
 		posting_time = (datetime.datetime.min + posting_time).time()
 
 	return datetime.datetime.combine(posting_date, posting_time).replace(microsecond=0)
+
+
+@frappe.request_cache
+def get_default_stock_uom() -> str | None:
+	if default_uom := frappe.get_cached_value("Stock Settings", None, "stock_uom"):
+		return default_uom
+
+	acceptable_default_uoms = dict.fromkeys(
+		(
+			"Nos",
+			# In the past, we used to create translated UOMs during initial setup.
+			# These could either be in the system language...
+			_("Nos", frappe.get_system_settings("language")),
+			# or the current user's language
+			_("Nos"),
+		)
+	)
+
+	available_default_uoms = frappe.db.get_values(
+		"UOM", {"name": ("in", tuple(acceptable_default_uoms))}, pluck="name"
+	)
+
+	return next((uom for uom in acceptable_default_uoms if uom in available_default_uoms), None)