fix(stock): reset bin when no stock ledger entries remain (#58362)

* fix(stock): reset bin when no stock ledger entries remain

update_bin() only writes bins reachable through prev_sle_dict, and that
dict is empty once the last live sle for an item and warehouse is
cancelled or deleted. actual_qty is still recomputed, but stock_value
and valuation_rate stay stale and a repost cannot heal them, so bin
totals drift permanently from the stock balance.

zero those bins after the normal update, guarded by a re-check that no
live sle exists. also drop the prev_sle_dict seeding added earlier in
initialize_previous_data, which never took effect because
initialize_reposting() discards the dict before update_bin() reads it.

* test(stock): cover bin reset when ledger is empty

three cases that all leave an item and warehouse with no live sle:
cancelling the only voucher, deleting it with delete_linked_ledger_entries
on, and reposting over an already emptied ledger. each asserts actual_qty,
valuation_rate and stock_value are all zero.

erpnext/stock/doctype/bin/test_bin.py

@@ -57,6 +57,68 @@ class TestBin(ERPNextTestSuite):
 		self.assertEqual(bin.valuation_rate, 0)
 		self.assertEqual(bin.stock_value, 0)
 
+	def test_repost_resets_bin_without_sle(self):
+		"""A repost must zero the bin when the ledger is empty, e.g. after entries were deleted."""
+		from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+		from erpnext.stock.stock_ledger import update_entries_after
+
+		item_code = make_item().name
+		warehouse = "_Test Warehouse - _TC"
+		make_stock_entry(item_code=item_code, target=warehouse, qty=10, rate=100)
+
+		# deleting a transaction with `delete_linked_ledger_entries` on drops its entries outright
+		frappe.db.delete("Stock Ledger Entry", {"item_code": item_code, "warehouse": warehouse})
+
+		update_entries_after(
+			{
+				"item_code": item_code,
+				"warehouse": warehouse,
+				"posting_date": "1900-01-01",
+				"posting_time": "00:01",
+			}
+		)
+
+		bin = frappe.get_doc("Bin", {"item_code": item_code, "warehouse": warehouse})
+		self.assertEqual(bin.actual_qty, 0)
+		self.assertEqual(bin.valuation_rate, 0)
+		self.assertEqual(bin.stock_value, 0)
+
+	def test_cancelling_last_entry_resets_bin(self):
+		"""Cancelling the only voucher must clear stock value, not just quantity."""
+		from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+
+		item_code = make_item().name
+		warehouse = "_Test Warehouse - _TC"
+		se = make_stock_entry(item_code=item_code, target=warehouse, qty=10, rate=100)
+
+		se.cancel()
+
+		bin = frappe.get_doc("Bin", {"item_code": item_code, "warehouse": warehouse})
+		self.assertEqual(bin.actual_qty, 0)
+		self.assertEqual(bin.valuation_rate, 0)
+		self.assertEqual(bin.stock_value, 0)
+
+	def test_deleting_last_voucher_resets_bin(self):
+		"""Deleting the only voucher wipes its ledger entries outright, the bin must still be cleared."""
+		from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+
+		item_code = make_item().name
+		warehouse = "_Test Warehouse - _TC"
+		delete_entries = frappe.get_single_value("Accounts Settings", "delete_linked_ledger_entries")
+		frappe.db.set_single_value("Accounts Settings", "delete_linked_ledger_entries", 1)
+
+		try:
+			se = make_stock_entry(item_code=item_code, target=warehouse, qty=10, rate=100)
+			se.cancel()
+			frappe.delete_doc("Stock Entry", se.name, force=1)
+		finally:
+			frappe.db.set_single_value("Accounts Settings", "delete_linked_ledger_entries", delete_entries)
+
+		bin = frappe.get_doc("Bin", {"item_code": item_code, "warehouse": warehouse})
+		self.assertEqual(bin.actual_qty, 0)
+		self.assertEqual(bin.valuation_rate, 0)
+		self.assertEqual(bin.stock_value, 0)
+
 	def test_index_exists(self):
 		# has_index is db-agnostic; raw "SHOW INDEX" is MySQL-only and errors on Postgres
 		if not frappe.db.has_index("tabBin", "unique_item_warehouse"):

erpnext/stock/stock_ledger.py

@@ -714,16 +714,6 @@ class update_entries_after:
 		previous_sle = get_previous_sle_of_current_voucher(args)
 		if previous_sle:
 			self.prev_sle_dict[(args.get("item_code"), args.get("warehouse"))] = previous_sle
-		else:
-			self.prev_sle_dict[(args.get("item_code"), args.get("warehouse"))] = frappe._dict(
-				{
-					"qty_after_transaction": 0.0,
-					"valuation_rate": 0.0,
-					"stock_value": 0.0,
-					"prev_stock_value": 0.0,
-					"stock_queue": [],
-				}
-			)
 
 		warehouse_dict.previous_sle = previous_sle
 
@@ -1951,6 +1941,30 @@ class update_entries_after:
 
 			frappe.db.set_value("Bin", bin_name, updated_values, update_modified=True)
 
+		self.reset_bin_without_stock_ledger_entries()
+
+	def reset_bin_without_stock_ledger_entries(self):
+		"""Reset the bin when its ledger has no entries left, prev_sle_dict never covers that case."""
+		item_code, warehouse = self.args.get("item_code"), self.args.get("warehouse")
+		if not item_code or not warehouse or (item_code, warehouse) in self.prev_sle_dict:
+			return
+
+		if frappe.db.exists(
+			"Stock Ledger Entry", {"item_code": item_code, "warehouse": warehouse, "is_cancelled": 0}
+		):
+			return
+
+		bin_name = frappe.db.get_value("Bin", {"item_code": item_code, "warehouse": warehouse})
+		if not bin_name:
+			return
+
+		frappe.db.set_value(
+			"Bin",
+			bin_name,
+			{"actual_qty": 0.0, "stock_value": 0.0, "valuation_rate": 0.0},
+			update_modified=True,
+		)
+
 
 def get_sle_against_current_voucher(kwargs):
 	kwargs["posting_datetime"] = get_combine_datetime(kwargs.posting_date, kwargs.posting_time)