fix removeAllChildren UB

Author: dankmeme01

loader/src/hooks/CCMenuSelectedFix.cpp

@@ -0,0 +1,35 @@
+#include <Geode/Geode.hpp>
+#include <Geode/utils/VMTHookManager.hpp>
+#include <Geode/modify/Traits.hpp>
+#include <Geode/modify/CCMenu.hpp>
+
+using namespace geode::prelude;
+
+struct CCMenuSelectedFix : Modify<CCMenuSelectedFix, CCMenu> {
+    bool initWithArray(CCArray* arr) {
+        if (!CCMenu::initWithArray(arr)) return false;
+
+        if (!exact_cast<CCMenu*>(this)) {
+            return true;
+        }
+
+        auto hook = VMTHookManager::get().addHook<
+            geode::modifier::ResolveC<CCMenuSelectedFix>::func(&CCMenuSelectedFix::removeAllChildren)
+        >(this, "cocos2d::CCMenu::removeAllChildren");
+
+        if (!hook) {
+            log::error("Failed to hook CCMenu::removeAllChildren: {}", hook.unwrapErr());
+        }
+
+        return true;
+    }
+
+    $override
+    void removeAllChildren() {
+        // CCMenu itself overrides `removeChild` to reset `m_pSelectedItem` and prevent UB.
+        // `removeAllChildren` is not overriden and never calls `removeChild`, thus not resetting this member.
+        // This fixes that, eliminating UB that can happen when spam clicking a button that removes itself with this method.
+        m_pSelectedItem = nullptr;
+        CCNode::removeAllChildren();
+    }
+};