fix: Item tax validity comparison fixes (#34784)

fix: Item tax validity comparsion fixes

erpnext/setup/doctype/item_group/item_group.py

@@ -36,8 +36,24 @@ class ItemGroup(NestedSet, WebsiteGenerator):
 
 		self.make_route()
 		self.validate_item_group_defaults()
+		self.check_item_tax()
 		ECommerceSettings.validate_field_filters(self.filter_fields, enable_field_filters=True)
 
+	def check_item_tax(self):
+		"""Check whether Tax Rate is not entered twice for same Tax Type"""
+		check_list = []
+		for d in self.get("taxes"):
+			if d.item_tax_template:
+				if (d.item_tax_template, d.tax_category) in check_list:
+					frappe.throw(
+						_("{0} entered twice {1} in Item Taxes").format(
+							frappe.bold(d.item_tax_template),
+							"for tax category {0}".format(frappe.bold(d.tax_category)) if d.tax_category else "",
+						)
+					)
+				else:
+					check_list.append((d.item_tax_template, d.tax_category))
+
 	def on_update(self):
 		NestedSet.on_update(self)
 		invalidate_cache_for(self)

erpnext/stock/doctype/item/item.py

@@ -351,10 +351,15 @@ class Item(Document):
 		check_list = []
 		for d in self.get("taxes"):
 			if d.item_tax_template:
-				if d.item_tax_template in check_list:
-					frappe.throw(_("{0} entered twice in Item Tax").format(d.item_tax_template))
+				if (d.item_tax_template, d.tax_category) in check_list:
+					frappe.throw(
+						_("{0} entered twice {1} in Item Taxes").format(
+							frappe.bold(d.item_tax_template),
+							"for tax category {0}".format(frappe.bold(d.tax_category)) if d.tax_category else "",
+						)
+					)
 				else:
-					check_list.append(d.item_tax_template)
+					check_list.append((d.item_tax_template, d.tax_category))
 
 	def validate_barcode(self):
 		import barcodenumber

erpnext/stock/get_item_details.py

@@ -637,7 +637,9 @@ def _get_item_tax_template(args, taxes, out=None, for_validate=False):
 				taxes_with_no_validity.append(tax)
 
 	if taxes_with_validity:
-		taxes = sorted(taxes_with_validity, key=lambda i: i.valid_from, reverse=True)
+		taxes = sorted(
+			taxes_with_validity, key=lambda i: i.valid_from or tax.maximum_net_rate, reverse=True
+		)
 	else:
 		taxes = taxes_with_no_validity