Attic stores hard link to inaccessible file

[cestrauss]

When there is a inaccessible file (ex. "chmod 0 file"), attic does not stores the file. However, if there is a hard link to this file, it is stored as a hard link to an unexisting file. Example:

$ mkdir work
$ echo hello > work/forbidden.txt
$ chmod 0 work/forbidden.txt 
$ ln work/forbidden.txt work/link.txt
$ attic init repo
Initializing repository at "repo"
Encryption NOT enabled.
Use the "--encryption=passphrase|keyfile" to enable encryption.
Initializing cache...
$ attic create repo::1 work
attic: work/forbidden.txt: [Errno 13] Permission denied: 'work/forbidden.txt'
attic: Exiting with failure status due to previous errors
$ attic list repo::1
drwxr-xr-x cstrauss cstrauss        0 Jan 21 16:06 work
h--------- cstrauss cstrauss        0 Jan 21 16:06 work/link.txt link to work/forbidden.txt
$ mkdir mnt
$ attic mount repo::1 mnt
Traceback (most recent call last):
  File "/usr/bin/attic", line 3, in <module>
    main()
  File "/usr/lib/python3.6/site-packages/attic/archiver.py", line 730, in main
    exit_code = archiver.run(sys.argv[1:])
  File "/usr/lib/python3.6/site-packages/attic/archiver.py", line 720, in run
    return args.func(args)
  File "/usr/lib/python3.6/site-packages/attic/archiver.py", line 262, in do_mount
    operations = AtticOperations(key, repository, manifest, archive)
  File "/usr/lib/python3.6/site-packages/attic/fuse.py", line 48, in __init__
    self.process_archive(archive)
  File "/usr/lib/python3.6/site-packages/attic/fuse.py", line 82, in process_archive
    inode = self._find_inode(item[b'source'], prefix)
  File "/usr/lib/python3.6/site-packages/attic/fuse.py", line 127, in _find_inode
    inode = self.contents[inode][segment]
KeyError: b'forbidden.txt'

$ mkdir extract
$ cd extract/
$ attic extract ../repo::1
attic: work/link.txt: [Errno 2] No such file or directory: '/tmp/attic2/extract/work/forbidden.txt' -> '/tmp/attic2/extract/work/link.txt'
attic: Exiting with failure status due to previous errors

I'm using Attic 0.16.