From 7a4fb2ddc15d1afd519d4a7a0ab1306c33f3f8bc Mon Sep 17 00:00:00 2001
From: Martin-Molinero <martin.molinero1@gmail.com>
Date: Fri, 19 Jun 2026 20:34:51 +0000
Subject: [PATCH] Cache cross-zero unsupported-order-type set in brokerage
 models

TastytradeBrokerageModel and TradeStationBrokerageModel declared
NotSupportedCrossZeroOrderTypes as an expression-bodied property, allocating a
new constant HashSet on every CanSubmitOrder call (used per order in
BrokerageExtensions.ValidateCrossZeroOrder). Make it a static readonly field,
built once, matching the existing BrokerageExtensions.DefaultNotSupportedCrossZeroOrderTypes
pattern. Set contents are unchanged, so cross-zero validation behavior is identical.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 Common/Brokerages/TastytradeBrokerageModel.cs   | 2 +-
 Common/Brokerages/TradeStationBrokerageModel.cs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Common/Brokerages/TastytradeBrokerageModel.cs b/Common/Brokerages/TastytradeBrokerageModel.cs
index cd81bc786d52..8671a9d11e92 100644
--- a/Common/Brokerages/TastytradeBrokerageModel.cs
+++ b/Common/Brokerages/TastytradeBrokerageModel.cs
@@ -55,7 +55,7 @@ public class TastytradeBrokerageModel : DefaultBrokerageModel
         /// <summary>
         /// The set of <see cref="OrderType"/> values that cannot be used for cross-zero execution.
         /// </summary>
-        private static IReadOnlySet<OrderType> NotSupportedCrossZeroOrderTypes => new HashSet<OrderType>()
+        private static readonly IReadOnlySet<OrderType> NotSupportedCrossZeroOrderTypes = new HashSet<OrderType>()
         {
             OrderType.ComboLimit
         };
diff --git a/Common/Brokerages/TradeStationBrokerageModel.cs b/Common/Brokerages/TradeStationBrokerageModel.cs
index 30309319b0d9..51e4fe5139e4 100644
--- a/Common/Brokerages/TradeStationBrokerageModel.cs
+++ b/Common/Brokerages/TradeStationBrokerageModel.cs
@@ -75,7 +75,7 @@ public class TradeStationBrokerageModel : DefaultBrokerageModel
         /// <summary>
         /// The set of <see cref="OrderType"/> values that cannot be used for cross-zero execution.
         /// </summary>
-        private static IReadOnlySet<OrderType> NotSupportedCrossZeroOrderTypes => new HashSet<OrderType>()
+        private static readonly IReadOnlySet<OrderType> NotSupportedCrossZeroOrderTypes = new HashSet<OrderType>()
         {
             OrderType.ComboMarket,
             OrderType.ComboLimit,