Fix inventory containers (#11944)

Content.Shared/Inventory/InventorySystem.Slots.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.CodeAnalysis;
 using Robust.Shared.Containers;
 using Robust.Shared.Prototypes;
 
@@ -8,6 +8,22 @@ public partial class InventorySystem : EntitySystem
 {
     [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
 
+    private void InitializeSlots()
+    {
+        SubscribeLocalEvent<InventoryComponent, ComponentInit>(OnInit);
+    }
+
+    protected virtual void OnInit(EntityUid uid, InventoryComponent component, ComponentInit args)
+    {
+        if (!_prototypeManager.TryIndex(component.TemplateId, out InventoryTemplatePrototype? invTemplate))
+            return;
+
+        foreach (var slot in invTemplate.Slots)
+        {
+            _containerSystem.EnsureContainer<ContainerSlot>(uid, slot.Name).OccludesLight = false;
+        }
+    }
+
     public bool TryGetSlotContainer(EntityUid uid, string slot, [NotNullWhen(true)] out ContainerSlot? containerSlot, [NotNullWhen(true)] out SlotDefinition? slotDefinition,
         InventoryComponent? inventory = null, ContainerManagerComponent? containerComp = null)
     {
@@ -21,9 +37,9 @@ public partial class InventorySystem : EntitySystem
 
         if (!containerComp.TryGetContainer(slotDefinition.Name, out var container))
         {
-            containerSlot = containerComp.MakeContainer<ContainerSlot>(slotDefinition.Name);
-            containerSlot.OccludesLight = false;
-            return true;
+            if (inventory.LifeStage >= ComponentLifeStage.Initialized)
+                Logger.Error($"Missing inventory container {slot} on entity {ToPrettyString(uid)}");
+            return false;
         }
 
         if (container is not ContainerSlot containerSlotChecked) return false;