VFS: Fix mounting non-existant paths (#13488)

rpcs3/Emu/VFS.cpp

@@ -71,6 +71,8 @@ bool vfs::mount(std::string_view vpath, std::string_view path, bool is_dir)
 		{
 			// Mounting completed; fixup for directories due to resolve_path messing with trailing /
 			list.back()->path = Emu.GetCallbacks().resolve_path(path);
+			if (list.back()->path.empty())
+				list.back()->path = std::string(path); // Fallback when resolving failed
 			if (is_dir && !list.back()->path.ends_with('/'))
 				list.back()->path += '/';
 			if (!is_dir && list.back()->path.ends_with('/'))

rpcs3/main_application.cpp

@@ -327,6 +327,7 @@ EmuCallbacks main_application::CreateCallbacks()
 
 	callbacks.resolve_path = [](std::string_view sv)
 	{
+		// May result in an empty string if path does not exist
 		return QFileInfo(QString::fromUtf8(sv.data(), static_cast<int>(sv.size()))).canonicalFilePath().toStdString();
 	};