Don't set OnPcEquip for items that failed to equip (Fixes #2776)

apps/openmw/mwgui/inventorywindow.cpp

@@ -436,6 +436,20 @@ namespace MWGui
     {
         const std::string& script = ptr.getClass().getScript(ptr);
 
+        MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayerPtr();
+
+        // early-out for items that need to be equipped, but can't be equipped: we don't want to set OnPcEquip in that case
+        if (!ptr.getClass().getEquipmentSlots(ptr).first.empty())
+        {
+            std::pair<int, std::string> canEquip = ptr.getClass().canBeEquipped(ptr, player);
+            if (canEquip.first == 0)
+            {
+                MWBase::Environment::get().getWindowManager()->messageBox(canEquip.second);
+                updateItemView();
+                return;
+            }
+        }
+
         // If the item has a script, set its OnPcEquip to 1
         if (!script.empty()
                 // Another morrowind oddity: when an item has skipped equipping and pcskipequip is reset to 0 afterwards,
@@ -455,7 +469,7 @@ namespace MWGui
         {
             boost::shared_ptr<MWWorld::Action> action = ptr.getClass().use(ptr);
 
-            action->execute (MWBase::Environment::get().getWorld()->getPlayerPtr());
+            action->execute (player);
 
             mSkippedToEquip = MWWorld::Ptr();
         }