fix: validate historical trade chain changes

src/grid_trading/services/trading_service.py

@@ -143,6 +143,15 @@ class TradingService:
         return self.save_trade(trade)
 
     def delete_trade(self, trade_id: int) -> None:
+        trade = self.repository.get_trade(trade_id)
+        if trade is None:
+            return
+        remaining_trades = [
+            existing
+            for existing in self.repository.list_trades(account_id=trade.account_id)
+            if existing.id != trade_id
+        ]
+        self._validate_trade_chain(remaining_trades)
         self.repository.delete_trade(trade_id)
 
     def list_trades(self, *, instrument_id: int | None = None) -> list[Trade]:
@@ -216,15 +225,21 @@ class TradingService:
             )
 
     def _validate_resulting_position(self, trade: Trade, existing_trades: list[Trade]) -> None:
+        self._validate_trade_chain([*existing_trades, trade])
+
+    def _validate_trade_chain(self, trades: list[Trade]) -> None:
+        if not trades:
+            return
         instruments = self.repository.list_instruments()
+        as_of = max(item.trade_date for item in trades)
         try:
             calculate_positions(
                 instruments,
-                [*existing_trades, trade],
-                as_of=trade.trade_date,
+                trades,
+                as_of=as_of,
             )
         except CalculationError as exc:
-            raise ValueError(str(exc)) from exc
+            raise ValueError(f"后续成交重算失败：{exc}") from exc
 
     def _instrument_cashflows(self, account_id: int) -> dict[int, Decimal]:
         totals: dict[int, Decimal] = defaultdict(lambda: Decimal("0"))

tests/test_services.py

@@ -129,3 +129,51 @@ def test_service_validates_lot_size_and_available_sell_quantity(tmp_path):
     )
 
     assert saved_sell.id is not None
+
+
+def test_service_rejects_historical_changes_that_break_future_sells(tmp_path):
+    service = TradingService(tmp_path / "grid.db")
+    service.ensure_defaults()
+    account = service.get_active_account()
+    instrument = service.add_instrument(Instrument(id=None, code="159915", name="创业板ETF"))
+    buy = service.save_trade(
+        Trade(
+            id=None,
+            account_id=account.id,
+            instrument_id=instrument.id,
+            trade_date=date(2026, 7, 7),
+            side=TradeSide.BUY,
+            price=Decimal("2.00"),
+            quantity=200,
+            trade_group=TradeGroup.GRID,
+        )
+    )
+    service.save_trade(
+        Trade(
+            id=None,
+            account_id=account.id,
+            instrument_id=instrument.id,
+            trade_date=date(2026, 7, 8),
+            side=TradeSide.SELL,
+            price=Decimal("2.10"),
+            quantity=200,
+            trade_group=TradeGroup.GRID,
+        )
+    )
+
+    with pytest.raises(ValueError, match="后续成交"):
+        service.update_trade(
+            Trade(
+                id=buy.id,
+                account_id=account.id,
+                instrument_id=instrument.id,
+                trade_date=date(2026, 7, 7),
+                side=TradeSide.BUY,
+                price=Decimal("2.00"),
+                quantity=100,
+                trade_group=TradeGroup.GRID,
+            )
+        )
+
+    with pytest.raises(ValueError, match="后续成交"):
+        service.delete_trade(buy.id)