Déjà Dup should verify if there is enough room to restore a backup in the destination folder

[Huygens]

As I described it in bug #332497 I was trying to restore a backup (~700MB) on my hard disk which had not enough available space (~400MB) to accommodate it.
I found out the problem after downloading the first 400MB, which took quite a while... Déjà Dup should check before restoring that the destination has enough room for the restored data. In case it is not possible, it should right away notify the user. Note that on some remote backup places (like Amazon S3), transfer has a cost (albeit small).

[Michael Terry (mterry)]

Yes, Déjà Dup should definitely check.

[Pete Goodall (pgoodall)]

I'm sure this is an implementation detail, but could we write some metadata for each backup, such as the backup date and time, the size required and maybe a file list. This would allow Deja Dup to know almost immediately that it does not have enough available space in either the cache dir or the destination dir. It also allows Deja Dup to come back much more quickly with the date and time of the backup you want to restore (rather that eating my cpu to get this information). The file list (which should probably be encrypted) might allow future functionality of either warning the user when they request to restore a non-existent directory or allowing the user to pick from a list of directories they wish to (or to not) restore.

[Christoph Michelbach (hj7-c)]

I want to note that it'd be nice if a restore wasn't made impossible. A mere Nautilus style "You don't have enough storage space. Do you want to do it anyway?" would be nice.

The reason for this is that if the restore takes place over a slow connection, there is plenty of time to clear space up (and I don't like unnecessary restrictions).

[Michael Terry (mterry)]

For restic backups, the not-yet-released 49.0 will use nautilus as the main restore interface, so this should be fixed via outsourcing the problem to them.

(Duplicity backups will continue using the in-app browser, but for default restic backups, the problem is solved.)