Skip done trades in error() to prevent late-error mutation

Mainly a pre-defensive update here since it _looks like it could happen_
but I've never seen any proof "delayed replay updates" happen live. More
of a logical protection fix against other condtions until we get a
better refactor of some of the long state-tracking-logic in place.

`Wrapper.error` looks up `self.trades[(clientId, reqId)]` whenever the
incoming reqId is non-negative, but `self.trades` never evicts
finished orders. A late or replayed error for a long-completed order
would silently:

  - flip its `OrderStatus.status` to `ValidationError` on the warning
    branch (corrupting the audit log of a Filled/Cancelled order); or
  - set `advancedError` on the trade in the error branch
    (`if not isDone()` only guards the cancel-mutation, not the
    `advancedError` assignment).

Treat done trades as absent at the lookup site so the rest of `error`
only acts on live orders. Live-order behavior is unchanged.

Author: mattsta

ib_async/wrapper.py

@@ -1678,6 +1678,14 @@ def error(
         # reqId is a local orderId, but is delivered as -1 if this is a non-order-related error
         if reqId != -1:
             trade = self.trades.get((self.clientId, reqId))
+            # Trades are never evicted from `self.trades`, so a late or
+            # replayed error for an already-finished order would otherwise
+            # corrupt its status (warning branch sets ValidationError) or
+            # set `advancedError` (error branch) on a completed trade.
+            # Treat done trades as absent here so the rest of the function
+            # only acts on live orders.
+            if trade and trade.isDone():
+                trade = None
 
         # Warnings are currently:
         # 105 - Order being modified does not match the original order. (?)

tests/test_error_done_trade.py

@@ -0,0 +1,62 @@
+"""Late/replayed errors for already-finished orders must not mutate them.
+
+`self.trades` is never evicted, so an error arriving for a long-finished
+orderId would otherwise:
+  - flip its status to ValidationError on the warning branch
+  - set its `advancedError` on the error branch
+
+Both are wrong: a Filled or Cancelled order is final.
+"""
+
+import ib_async as ibi
+from ib_async.order import Order, OrderState, OrderStatus, Trade
+
+
+def _doneTrade(ib, *, orderId=1, permId=42, status=OrderStatus.Filled):
+    contract = ibi.Stock("ABC", "SMART", "USD")
+    contract.conId = 12345
+    order = Order(orderId=orderId, clientId=ib.wrapper.clientId, permId=permId)
+    orderStatus = OrderStatus(orderId=orderId, status=status)
+    trade = Trade(contract, order, orderStatus, [], [])
+    ib.wrapper.trades[(ib.wrapper.clientId, orderId)] = trade
+    return trade
+
+
+def test_warning_error_does_not_mutate_filled_trade():
+    ib = ibi.IB()
+    ib.wrapper.clientId = 0
+    trade = _doneTrade(ib, orderId=1, status=OrderStatus.Filled)
+
+    # 105 is in the warning code set
+    ib.wrapper.error(reqId=1, errorCode=105, errorString="late warning",
+                     advancedOrderRejectJson="")
+
+    assert trade.orderStatus.status == OrderStatus.Filled
+    assert trade.log == []
+
+
+def test_error_does_not_set_advancedError_on_cancelled_trade():
+    ib = ibi.IB()
+    ib.wrapper.clientId = 0
+    trade = _doneTrade(ib, orderId=2, status=OrderStatus.Cancelled)
+    assert trade.advancedError == ""
+
+    # 201 is a non-warning order error code
+    ib.wrapper.error(reqId=2, errorCode=201, errorString="late reject",
+                     advancedOrderRejectJson='{"foo":"bar"}')
+
+    assert trade.advancedError == ""
+    assert trade.orderStatus.status == OrderStatus.Cancelled
+
+
+def test_warning_error_still_mutates_live_trade():
+    """Sanity: the live-trade path must remain intact."""
+    ib = ibi.IB()
+    ib.wrapper.clientId = 0
+    trade = _doneTrade(ib, orderId=3, status=OrderStatus.Submitted)
+
+    ib.wrapper.error(reqId=3, errorCode=105, errorString="live warning",
+                     advancedOrderRejectJson="")
+
+    assert trade.orderStatus.status == OrderStatus.ValidationError
+    assert len(trade.log) == 1