fix: don't reset rate if greater than zero in standalone debit note (…

…backport #37935) (#37940)

* fix: don't reset rate if greater than zero in standalone debit note

(cherry picked from commit 5cce522)

* fix(test): `test_gl_entries_for_standalone_debit_note`

(cherry picked from commit f9fc6c9)

---------

Co-authored-by: s-aga-r <sagarsharma.s312@gmail.com>
(cherry picked from commit 64658fc)

erpnext/accounts/doctype/purchase_invoice/test_purchase_invoice.py

@@ -1718,9 +1718,14 @@ def test_batch_expiry_for_purchase_invoice(self):
 		self.assertTrue(return_pi.docstatus == 1)
 
 	def test_gl_entries_for_standalone_debit_note(self):
-		make_purchase_invoice(qty=5, rate=500, update_stock=True)
+		from erpnext.stock.doctype.item.test_item import make_item
 
-		returned_inv = make_purchase_invoice(qty=-5, rate=5, update_stock=True, is_return=True)
+		item_code = make_item(properties={"is_stock_item": 1})
+		make_purchase_invoice(item_code=item_code, qty=5, rate=500, update_stock=True)
+
+		returned_inv = make_purchase_invoice(
+			item_code=item_code, qty=-5, rate=5, update_stock=True, is_return=True
+		)
 
 		# override the rate with valuation rate
 		sle = frappe.get_all(
@@ -1730,7 +1735,7 @@ def test_gl_entries_for_standalone_debit_note(self):
 		)[0]
 
 		rate = flt(sle.stock_value_difference) / flt(sle.actual_qty)
-		self.assertAlmostEqual(returned_inv.items[0].rate, rate)
+		self.assertAlmostEqual(rate, 500)
 
 	def test_payment_allocation_for_payment_terms(self):
 		from erpnext.buying.doctype.purchase_order.test_purchase_order import (

erpnext/controllers/buying_controller.py

@@ -78,26 +78,26 @@ def onload(self):
 	def set_rate_for_standalone_debit_note(self):
 		if self.get("is_return") and self.get("update_stock") and not self.return_against:
 			for row in self.items:
+				if row.rate <= 0:
+					# override the rate with valuation rate
+					row.rate = get_incoming_rate(
+						{
+							"item_code": row.item_code,
+							"warehouse": row.warehouse,
+							"posting_date": self.get("posting_date"),
+							"posting_time": self.get("posting_time"),
+							"qty": row.qty,
+							"serial_and_batch_bundle": row.get("serial_and_batch_bundle"),
+							"company": self.company,
+							"voucher_type": self.doctype,
+							"voucher_no": self.name,
+						},
+						raise_error_if_no_rate=False,
+					)
 
-				# override the rate with valuation rate
-				row.rate = get_incoming_rate(
-					{
-						"item_code": row.item_code,
-						"warehouse": row.warehouse,
-						"posting_date": self.get("posting_date"),
-						"posting_time": self.get("posting_time"),
-						"qty": row.qty,
-						"serial_and_batch_bundle": row.get("serial_and_batch_bundle"),
-						"company": self.company,
-						"voucher_type": self.doctype,
-						"voucher_no": self.name,
-					},
-					raise_error_if_no_rate=False,
-				)
-
-				row.discount_percentage = 0.0
-				row.discount_amount = 0.0
-				row.margin_rate_or_amount = 0.0
+					row.discount_percentage = 0.0
+					row.discount_amount = 0.0
+					row.margin_rate_or_amount = 0.0
 
 	def set_missing_values(self, for_validate=False):
 		super(BuyingController, self).set_missing_values(for_validate)