App name is duplicated on Windows if author name is missing or None

• Python version: 3.9
• appdirs version: 1.4.4

Linux:

>>> appdirs.user_data_dir('foo')
'/home/user/.local/share/foo'

Windows:

>>> appdirs.user_data_dir('foo')
'C:\\Users\\user\\AppData\\Local\\foo\\foo'

Specifying an empty string as second argument works to avoid this issue.

[YariKartoshe4ka]

Noone forces you to have two levels of directories if you read the doc string

"appauthor" (only used on Windows) is the name of the
            appauthor or distributing body for this application. Typically
            it is the owning company name. This falls back to appname. You may
            pass False to disable it.

I think this behavior is not very useful, but it can still help. Also some companies use subderictories e.g.: Mozilla (“Mozilla” dir has subdir “Firefox”, Opera (“Opera Software” dir has subdir “Opera Stable” etc)

[YariKartoshe4ka]

I’m not a big Windows connoisseur, but most likely it’s just a good tone rule that doesn’t have to be followed… Hack with '' will be work until os.path.join has same bevavior

>>> os.path.join('foo', '', 'bar')
'foo/bar'