Description
The function GlobalCacheTracker::get_registry_items_to_clean_size_both is responsible for manual gc cleaning when the --max-download-size option is specified. When determining what to delete, it scans both the src and .crate files.
An issue is that if it deletes a .crate file without deleting its corresponding src directory, the src directory becomes orphaned and unusuable, which results in a waste of disk space. Eventually it will be reclaimed during future cache cleaning. It would be nice if it made sure that the src gets removed if a .crate file is removed. However, this might be difficult to implement and not worth the complexity, so I'm not sure if this should be done or not.
This may not happen in practice due to the way sorting works (generally the src and .crate should have the same timestamp, and it should sort the src before the .crate). If that's the case, then this issue can probably be closed (and remove the TODO comment in the code).