fix(postgres): use portable DateDiff/CurDate in Inactive Sales Items report

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

erpnext/accounts/report/inactive_sales_items/inactive_sales_items.py

@@ -4,7 +4,7 @@
 
 import frappe
 from frappe import _
-from frappe.query_builder import CustomFunction
+from frappe.query_builder.functions import CurDate, DateDiff
 from frappe.utils import cint
 
 
@@ -102,11 +102,11 @@ def get_sales_details(filters):
 	child_doctype = "Sales Order Item" if filters["based_on"] == "Sales Order" else "Sales Invoice Item"
 	child = frappe.qb.DocType(child_doctype)
 
-	date_diff = CustomFunction("DATEDIFF", ["d1", "d2"])
-	current_date = CustomFunction("CURRENT_DATE", [])
-
 	date_col = parent.transaction_date if filters["based_on"] == "Sales Order" else parent.posting_date
-	days_since_last_order = date_diff(current_date(), date_col)
+
+	# DateDiff is cross-database (DATEDIFF on MariaDB, date subtraction on postgres); CurDate()
+	# renders the bare CURRENT_DATE keyword. Yields the integer number of days.
+	days_since_last_order = DateDiff(CurDate(), date_col)
 
 	sales_data = (
 		frappe.qb.from_(parent)

erpnext/accounts/report/inactive_sales_items/test_inactive_sales_items.py

@@ -0,0 +1,32 @@
+# Copyright (c) 2024, Frappe Technologies Pvt. Ltd. and contributors
+# For license information, please see license.txt
+
+import frappe
+from frappe.utils import add_days, today
+
+from erpnext.accounts.report.inactive_sales_items.inactive_sales_items import execute
+from erpnext.selling.doctype.sales_order.test_sales_order import make_sales_order
+from erpnext.stock.doctype.item.test_item import make_item
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestInactiveSalesItems(ERPNextTestSuite):
+	def test_days_since_last_order_is_computed(self):
+		# Exercises the date-arithmetic path (DATEDIFF/CURRENT_DATE on mariadb, date subtraction on
+		# postgres) which must produce the same integer day count on both databases.
+		item = make_item("_Test Inactive Sales Item").name
+		old_date = add_days(today(), -120)
+		so = make_sales_order(item=item, qty=3, rate=150, transaction_date=old_date)
+		so.items[0].delivery_date = add_days(old_date, 7)
+		so.save()
+		so.submit()
+
+		columns, data = execute(frappe._dict({"based_on": "Sales Order", "days": 30}))
+		self.assertTrue(columns)
+		row = next((r for r in data if r.get("item") == item and r.get("days_since_last_order")), None)
+		self.assertIsNotNone(row, "Inactive item should appear in the report")
+		self.assertGreaterEqual(row["days_since_last_order"], 30)
+
+	def test_report_runs_for_sales_invoice(self):
+		columns, _data = execute(frappe._dict({"based_on": "Sales Invoice", "days": 30}))
+		self.assertTrue(columns)