[Errno 18] Invalid cross-device link when doing `bak down`

[dhasial]

So whenever I do bak up, it works, but I also get An error occurred. after the bakfile is made.

And then when I try to do bak down to restore the test file, I get:

Overwrite /home/user/src/bak/TEST? [y/N]: y
Confirm: Restore /home/user/src/bak/TEST to /home/user/src/bak/TEST and erase bakfiles? [y/N]: y
Traceback (most recent call last):
  File "/usr/local/bin/bak", line 33, in <module>
    sys.exit(load_entry_point('bak==0.0.2a1', 'console_scripts', 'bak')())
  File "/usr/lib/python3/dist-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3/dist-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3/dist-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python3.9/dist-packages/bak-0.0.2a1-py3.9.egg/bak/__main__.py", line 102, in bak_down
  File "/usr/local/lib/python3.9/dist-packages/bak-0.0.2a1-py3.9.egg/bak/commands/__init__.py", line 274, in bak_down_cmd
  File "/usr/lib/python3.9/pathlib.py", line 1377, in rename
    self._accessor.rename(self, target)
OSError: [Errno 18] Invalid cross-device link: '/root/.local/share/bak/bakfiles/home-user-src-bak-TEST.1613262086-135462.bak' -> '/home/user/src/bak/TEST'

I've been messing around with bak reinstalling and such, but this happens after I've fully uninstalled any past installation and deleted, I believe, all the leftover files. It's possible this might be a permissions problem, but I recently recursively chowned and chmodded my homedir to 751 so that's probably not it. Also, it seemed to work pretty flawlessly on the very first install, no errors with bak up, bak down or anything else.

[ChanceNCounter]

Fascinating. shutil shouldn't do this.

[ChanceNCounter]

I'm also slightly concerned that the bakfile directory is in root's home folder.

[ChanceNCounter]

Right. Having slept, a couple clarifying questions:

• Is your home directory on another partition? (Mine is, shouldn't matter, but the linking error is a linking error)
• Did you sudo install bak, or have you run it as sudo?
• Do you have both /root/.local/share/bak and /home/user/.local/share/bak going? Unless you set $XDG_DATA_HOME to the former, you should only have the latter.

[ChanceNCounter]

I'm unable to repro, but I suspect the PR above this comment will fix it.

[dhasial]

1) Yes, my home directory is on another partition than root.

2) Yes, I did sudo python3 setup.py install --force because there were permission errors when trying to install without sudo:

python3 setup.py install --force
running install
error: can't create or remove files in install directory

The following error occurred while trying to add or remove files in the
installation directory:

    [Errno 13] Permission denied: '/usr/local/lib/python3.9/dist-packages/test-easy-install-1074937.write-test'

The installation directory you specified (via --install-dir, --prefix, or
the distutils default setting) was:

    /usr/local/lib/python3.9/dist-packages/

Perhaps your account does not have write access to this directory?  If the
installation directory is a system-owned directory, you may need to sign in
as the administrator or "root" account.  If you do not have administrative
access to this machine, you may wish to choose a different installation
directory, preferably one that is listed in your PYTHONPATH environment
variable.

For information on other options, you may wish to consult the
documentation at:

  https://setuptools.readthedocs.io/en/latest/easy_install.html

Please make the appropriate changes for your system and try again.

Also, at one point I did sudo pip3 uninstall, which worked, because doing the normal pip3 uninstall gave me the following error message:

ERROR: Exception:
Traceback (most recent call last):
  File "/usr/lib/python3.9/shutil.py", line 806, in move
    os.rename(src, real_dst)
PermissionError: [Errno 13] Permission denied: '/usr/local/lib/python3.9/dist-packages/bak-0.0.2a1-py3.9.egg' -> '/tmp/pip-uninstall-_s2ieye4/bak-0.0.2a1-py3.9.egg'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/cli/base_command.py", line 189, in _main
    status = self.run(options, args)
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/commands/uninstall.py", line 87, in run
    uninstall_pathset = req.uninstall(
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/req/req_install.py", line 658, in uninstall
    uninstalled_pathset.remove(auto_confirm, verbose)
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/req/req_uninstall.py", line 400, in remove
    moved.stash(path)
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/req/req_uninstall.py", line 289, in stash
    renames(path, new_path)
  File "/home/USER/.local/lib/python3.9/site-packages/pip/_internal/utils/misc.py", line 347, in renames
    shutil.move(old, new)
  File "/usr/lib/python3.9/shutil.py", line 821, in move
    os.unlink(src)
PermissionError: [Errno 13] Permission denied: '/usr/local/lib/python3.9/dist-packages/bak-0.0.2a1-py3.9.egg'

3) When I first installed bak, I set $XDG_DATA_HOME to /home/user/.local/share and haven't changed it since then but probably using sudo to install forced bak to use the /root/.local/share/bak instead.

My memory is crap so I wrote out this whole thing before looking closer at my logs to see I ended up needing to install it with sudo because of the permissions, and ended up rewriting this. Hopefully it's better information, and sorry for any clutter / confusion.

[ChanceNCounter]

That latest commit is master now, it needed merging regardless.

The time you tried sudo bak up might be responsible for root's bak dir. I'll have to check if bak up does firstrun stuff (should spin that off into a function of its own.)

This also raises the issue of sudo bak down.

[dhasial]

I rewrote my comment, forgot I did install with sudo.

I should mention that it would be nice to be able to run the command both as sudo and as a nonprivileged user and I'm not sure if there's any way to do that right now.

[ChanceNCounter]

Indeed. That'll require some thought to achieve.

[ChanceNCounter]

I don't know if I mentioned it, but I went with falling back on sudo cp after a PermissionError. That might evolve in the future.

Also dunno why this issue wasn't closed automatically when that branch was merged, it usually works.