Merge pull request #57722 from frappe/mergify/bp/version-16-hotfix/pr-57645

fix(purchase): reject purchase returns where every item has zero quan… (backport #57645)

erpnext/controllers/sales_and_purchase_return.py

@@ -159,10 +159,21 @@ def validate_returned_items(doc):
 				):
 					frappe.throw(_("Warehouse is mandatory"))
 
-			items_returned = True
+			if doc.doctype in ("Purchase Invoice", "Purchase Receipt", "Subcontracting Receipt"):
+				if flt(d.qty) < 0 or flt(d.get("received_qty")) < 0:
+					items_returned = True
+			else:
+				items_returned = True
 
 		elif d.item_name:
-			items_returned = True
+			if doc.doctype in ("Purchase Invoice", "Purchase Receipt", "Subcontracting Receipt"):
+				# No item_code here means no linked Item, so there's no accepted/rejected
+				# split to speak of - received_qty isn't a meaningful independent signal.
+				# Only a negative qty (i.e. a real negative billing amount) counts.
+				if flt(d.qty) < 0:
+					items_returned = True
+			else:
+				items_returned = True
 
 	if not items_returned:
 		frappe.throw(_("At least one item should be entered with negative quantity in return document"))

erpnext/controllers/tests/test_sales_and_purchase_return.py

@@ -0,0 +1,58 @@
+# Copyright (c) 2025, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestSalesAndPurchaseReturn(ERPNextTestSuite):
+	@staticmethod
+	def _cancel_and_delete(doctype, name):
+		if not frappe.db.exists(doctype, name):
+			return
+		doc = frappe.get_doc(doctype, name)
+		if doc.docstatus == 1:
+			doc.cancel()
+		frappe.delete_doc(doctype, name, force=1)
+
+	def test_purchase_invoice_zero_qty_return_is_rejected(self):
+		# A return with every item at qty 0 moves no stock and no value, so it must be
+		# rejected the same way a return with no items at all would be.
+		from erpnext.accounts.doctype.purchase_invoice.test_purchase_invoice import make_purchase_invoice
+
+		pi = make_purchase_invoice(qty=10)
+		self.addCleanup(self._cancel_and_delete, "Purchase Invoice", pi.name)
+
+		return_pi = make_purchase_invoice(
+			is_return=1,
+			return_against=pi.name,
+			qty=0,
+			do_not_save=True,
+		)
+
+		self.assertRaises(frappe.ValidationError, return_pi.save)
+
+	def test_purchase_invoice_item_name_only_zero_qty_return_is_rejected(self):
+		# Item Code is not mandatory on Purchase Invoice Item - a row can have only an
+		# item_name (e.g. a free-text/non-stock line). Such rows fall through to the
+		# item_name-only branch, which must also reject an all-zero-qty return instead
+		# of unconditionally treating the row as returned.
+		from erpnext.accounts.doctype.purchase_invoice.test_purchase_invoice import make_purchase_invoice
+
+		pi = make_purchase_invoice(item_name="_Test Item", qty=10, do_not_submit=True)
+		pi.items[0].item_code = ""
+		pi.save()
+		pi.submit()
+		self.addCleanup(self._cancel_and_delete, "Purchase Invoice", pi.name)
+
+		return_pi = make_purchase_invoice(
+			item_name="_Test Item",
+			is_return=1,
+			return_against=pi.name,
+			qty=0,
+			do_not_save=True,
+		)
+		return_pi.items[0].item_code = ""
+
+		self.assertRaises(frappe.ValidationError, return_pi.save)