Core/Scripting: Added missing hotswap code for SceneScripts

src/server/game/Scripting/ScriptMgr.cpp

@@ -662,6 +662,35 @@ class ScriptRegistrySwapHooks<InstanceMapScript, Base>
     bool swapped;
 };
 
+/// This hook is responsible for swapping SceneScript's
+template<typename Base>
+class ScriptRegistrySwapHooks<SceneScript, Base>
+    : public ScriptRegistrySwapHookBase
+{
+public:
+    ScriptRegistrySwapHooks() : swapped(false) { }
+
+    void BeforeReleaseContext(std::string const& context) final override
+    {
+        auto const bounds = static_cast<Base*>(this)->_ids_of_contexts.equal_range(context);
+        if (bounds.first != bounds.second)
+            swapped = true;
+    }
+
+    void BeforeSwapContext(bool /*initialize*/) override
+    {
+        swapped = false;
+    }
+
+    void BeforeUnload() final override
+    {
+        ASSERT(!swapped);
+    }
+
+private:
+    bool swapped;
+};
+
 /// This hook is responsible for swapping SpellScriptLoader's
 template<typename Base>
 class ScriptRegistrySwapHooks<SpellScriptLoader, Base>