Merge branch 'dont_remove_items_from_saves' into 'master'

Fix #7491. Alternative to !3258

Closes #7491

See merge request OpenMW/openmw!3266

apps/openmw/mwworld/cellstore.cpp

@@ -277,9 +277,17 @@ namespace
                     return;
                 }
 
-            Log(Debug::Warning) << "Warning: Dropping reference to " << state.mRef.mRefID
-                                << " (invalid content file link)";
-            return;
+            // Note: we preserve RefNum when picking up or dropping an item. So if this RefNum is not found
+            // in this cell in content files, it doesn't mean that the instance is invalid.
+            // But non-storable item are always stored in saves together with their original cell.
+            // If a non-storable item references a content file, but is not found in this content file,
+            // we should drop it.
+            if (!MWWorld::ContainerStore::isStorableType<T>())
+            {
+                Log(Debug::Warning) << "Warning: Dropping reference to " << state.mRef.mRefID
+                                    << " (invalid content file link)";
+                return;
+            }
         }
 
         // new reference

apps/openmw/mwworld/containerstore.hpp

@@ -99,6 +99,19 @@ namespace MWWorld
 
         static const ESM::RefId sGoldId;
 
+        static constexpr bool isStorableType(unsigned int t)
+        {
+            return t == ESM::Potion::sRecordId || t == ESM::Apparatus::sRecordId || t == ESM::Armor::sRecordId
+                || t == ESM::Book::sRecordId || t == ESM::Clothing::sRecordId || t == ESM::Ingredient::sRecordId
+                || t == ESM::Light::sRecordId || t == ESM::Lockpick::sRecordId || t == ESM::Miscellaneous::sRecordId
+                || t == ESM::Probe::sRecordId || t == ESM::Repair::sRecordId || t == ESM::Weapon::sRecordId;
+        }
+        template <typename T>
+        static constexpr bool isStorableType()
+        {
+            return isStorableType(T::sRecordId);
+        }
+
     protected:
         ContainerStoreListener* mListener;