delete() ignores a dj.Top restriction and deletes every matching row #1589

delete() and delete_quick() ignore a dj.Top restriction and delete every row that matches the expression's other conditions.

Item.insert([(i,) for i in range(5)])
(Item & dj.Top(2, order_by="item_id")).delete(prompt=False)
len(Item())   # 0 — expected 3

dj.Top is an ORDER BY ... LIMIT, kept in the expression's _top, not in its WHERE clause. Diagram.cascade builds the seed from table_expr.restriction only, and delete_quick uses where_clause() only, so both drop the Top. With no other condition, the whole table is deleted, along with its descendants. Diagram.trace has the same seed problem.

Workaround until the fix ships: restrict by the keys instead, (Item & (Item & dj.Top(2, order_by="item_id")).keys()).delete(). The delete prompt also shows the row counts before anything is deleted.

Fix: a seed restricted by Top is replaced by the primary keys it selects, in cascade, trace and delete_quick.