From 41ecaa27d0f300178f32a4c33d7a7e55101115d3 Mon Sep 17 00:00:00 2001
From: Leah <leahcatdev@gmail.com>
Date: Sat, 18 Jul 2026 12:11:28 +0200
Subject: [PATCH] fix unhandled ArgumentException when a duplicate shop cost
 modifier is added (#42064)

* add map containskey check

* review

---------

Co-authored-by: AJCM-git <ajcm_mail@disroot.org>
---
 Content.Shared/Store/ListingPrototype.cs | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Content.Shared/Store/ListingPrototype.cs b/Content.Shared/Store/ListingPrototype.cs
index 00d912ede9..a45c020526 100644
--- a/Content.Shared/Store/ListingPrototype.cs
+++ b/Content.Shared/Store/ListingPrototype.cs
@@ -346,11 +346,10 @@ public sealed partial class ListingDataWithCostModifiers : ListingData
     /// <param name="modifiers">Values for cost modification.</param>
     public void AddCostModifier(string modifierSourceId, Dictionary<ProtoId<CurrencyPrototype>, FixedPoint2> modifiers)
     {
-        CostModifiersBySourceId.Add(modifierSourceId, modifiers);
+        CostModifiersBySourceId.TryAdd(modifierSourceId, modifiers);
+
         if (_costModified != null)
-        {
             _costModified = ApplyAllModifiers();
-        }
     }
 
     /// <summary> Remove cost modifier with passed sourceId. </summary>