Qt: Fix empty gamesettings ini being saved on close

src/core/fullscreenui_settings.cpp

@@ -2114,10 +2114,12 @@ void FullscreenUI::DrawSettingsWindow()
     if (s_settings_locals.game_settings_interface)
     {
       Error error;
-      s_settings_locals.game_settings_interface->RemoveEmptySections();
 
       if (s_settings_locals.game_settings_interface->IsEmpty())
       {
+        // prevent empty ini from being saved if it was modified and transitioned back to empty
+        s_settings_locals.game_settings_interface->SetDirty(false);
+
         if (FileSystem::FileExists(s_settings_locals.game_settings_interface->GetPath().c_str()))
         {
           INFO_LOG("Removing empty game settings {}", s_settings_locals.game_settings_interface->GetPath());
@@ -2131,6 +2133,8 @@ void FullscreenUI::DrawSettingsWindow()
       }
       else
       {
+        s_settings_locals.game_settings_interface->RemoveEmptySections();
+
         if (!s_settings_locals.game_settings_interface->Save(&error))
         {
           OpenInfoMessageDialog(

src/duckstation-qt/qthost.cpp

@@ -683,6 +683,9 @@ bool QtHost::SaveGameSettings(SettingsInterface* sif, bool delete_if_empty)
   {
     INFO_LOG("Removing empty gamesettings ini {}", Path::GetFileName(ini->GetPath()));
 
+    // prevent empty ini from being saved if it was modified and transitioned back to empty
+    ini->SetDirty(false);
+
     // grab the settings lock while we're writing the file, that way the CPU thread doesn't try
     // to read it at the same time.
     const auto lock = Core::GetSettingsLock();

src/duckstation-qt/settingswindow.cpp

@@ -77,6 +77,9 @@ SettingsWindow::SettingsWindow(const GameList::Entry* entry, std::unique_ptr<INI
 
 SettingsWindow::~SettingsWindow()
 {
+  if (m_sif && m_sif->IsDirty()) [[unlikely]]
+    WARNING_LOG("File {} was dirty when SettingsWindow was closed", Path::GetFileName(m_sif->GetPath()));
+
   if (isPerGameSettings())
     s_open_game_properties_dialogs.removeOne(this);
 }

src/util/ini_settings_interface.cpp

@@ -31,6 +31,11 @@ INISettingsInterface::~INISettingsInterface()
     Save();
 }
 
+void INISettingsInterface::SetDirty(bool dirty)
+{
+  m_dirty = dirty;
+}
+
 void INISettingsInterface::SetPath(std::string path)
 {
   m_dirty |= (path != m_path);

src/util/ini_settings_interface.h

@@ -41,6 +41,7 @@ public:
 
   ALWAYS_INLINE bool IsDirty() const { return m_dirty; }
   ALWAYS_INLINE const std::string& GetPath() const { return m_path; }
+  void SetDirty(bool dirty);
   void SetPath(std::string path);
 
   bool Load(Error* error = nullptr);