Even if the GTK cache returns an empty result (result.size() == 0), the code executes subDirs.clear() and then attempts to populate subDirs with the empty result. This causes the subsequent icon file search loop (the for loop starting on line 507) to have no subdirectories to search, thereby failing to locate icon files that actually exist (such as those in the hicolor theme).

Reproduction steps:

1. Launch the demo application, which periodically scans desktop application icons.
   2. Download several applications; you will observe that the retrieved qicon information appears null. However, restarting the demo allows it to correctly identify the corresponding qicon information.