Comment 6 for bug 153054

Well, basically its a question of how to sanely detect and handle the presence/removal of such drives, while also automatically handling actual file deletions. The current system is based exclusively on file paths. So while we could detect the separate filesystem when its mounted, once its unmounted there's no way to distinguish between deletion and being unmounted. This means that, for EVERY FILE we would have to store some identifier for what filesystem its on, and be able to know whether that fs is mounted/unmounted, and check all of those at start. Not very ideal, to say the least.

Another way of handling it could be to just say that if you want a feature like this it must be registered as a separate library, which could be given a "not always present" mark or something like that. Then we just check files to be sure that their library is mounted (easy as the library path will be the same as the start of the file's path), and only if it is, should we attempt to handle the file. This is doable, but a fair chunk of work.

Also, this is a use case that only affects a very small percentage of users and it is thus very low on the list of things to do. It's a legitimate concern, and is likely to be implemented eventually, but don't hold your breath. However, patches are, as always, welcome, as are additional ideas on how to best handle the detection and handling of mounts.