fix: some crashes

src/modules/sni/host.cpp

@@ -59,7 +59,7 @@ void Host::nameVanished(const Glib::RefPtr<Gio::DBus::Connection>& conn, const G
 
 void Host::proxyReady(GObject* src, GAsyncResult* res, gpointer data) {
   GError* error = nullptr;
-  waybar::util::ScopeGuard error_deleter([error]() {
+  waybar::util::ScopeGuard error_deleter([&error]() {
     if (error != nullptr) {
       g_error_free(error);
     }
@@ -81,7 +81,7 @@ void Host::proxyReady(GObject* src, GAsyncResult* res, gpointer data) {
 
 void Host::registerHost(GObject* src, GAsyncResult* res, gpointer data) {
   GError* error = nullptr;
-  waybar::util::ScopeGuard error_deleter([error]() {
+  waybar::util::ScopeGuard error_deleter([&error]() {
     if (error != nullptr) {
       g_error_free(error);
     }

src/modules/sni/item.cpp

@@ -365,13 +365,14 @@ Glib::RefPtr<Gdk::Pixbuf> Item::extractPixBuf(GVariant* variant) {
 
 void Item::updateImage() {
   auto pixbuf = getIconPixbuf();
+  if (!pixbuf) return;
   auto scaled_icon_size = getScaledIconSize();
 
   // If the loaded icon is not square, assume that the icon height should match the
   // requested icon size, but the width is allowed to be different. As such, if the
   // height of the image does not match the requested icon size, resize the icon such that
   // the aspect ratio is maintained, but the height matches the requested icon size.
-  if (pixbuf->get_height() != scaled_icon_size) {
+  if (pixbuf->get_height() > 0 && pixbuf->get_height() != scaled_icon_size) {
     int width = scaled_icon_size * pixbuf->get_width() / pixbuf->get_height();
     pixbuf = pixbuf->scale_simple(width, scaled_icon_size, Gdk::InterpType::INTERP_BILINEAR);
   }

src/modules/sni/watcher.cpp

@@ -31,7 +31,7 @@ Watcher::~Watcher() {
 
 void Watcher::busAcquired(const Glib::RefPtr<Gio::DBus::Connection>& conn, Glib::ustring name) {
   GError* error = nullptr;
-  waybar::util::ScopeGuard error_deleter([error]() {
+  waybar::util::ScopeGuard error_deleter([&error]() {
     if (error) {
       g_error_free(error);
     }