Exception: raise TypeError(f'{funcname}() argument must be str, bytes, or ; due to mistake in ABLog config handling with multiple langua

[AlbertMietus]

When Sphinx/ABlog is configured with multiple languages, like

blog_languages = {
    'nl'  : ('Nederlands', None),
    'en'  : ('English', None)
}

post.generate_atom_feeds() on line 684 goes (or can go) wrong

if len(blog.blog_languages) > 1:
        base_url = os_path_join(url, app.config.language)

When that unrelated [app.config] language setting is not set (default), it's None. Which is a not allowed parameter in os-join-path (in generi Path; that is ultimately called).

To Reproduce

Create a setting with 2 (or more) blog_languages, as shown above. The related setting blog_default_language is a relevant. And enable atom-feed (default)

Then it goes wrong.

Remove that setting, or when it dict has length=1. It work

Fix (suggestions)

• Check the value of app.config.language; when none, do not use
• Use the value of blog_default_language (when not none)
• When no default is available, use the first key (or any) of the blog.blog_languages dict.

note: When that dict has no entries, the issue does not arise

[SilverRainZ]

May be related to #136.

[nabobalis]

I thought I would try to fix this in #142
Changing to make sure that join() never gets a None value was simple enough but as far as I can see, the url should never have the language set in the URL. So I removed that block of code instead.

It should be in the next release of ablog.