Internal link gives different URL in placeholder vs static placeholder

[jasper-flux]

The URL generated for internal links to the current site differs depending on whether the plugin is located in a static placeholder or a regular placeholder.

In a regular placeholder, a link in the format /<slug> is generated.
In a static placeholder, a link in the format //example.com/<slug> is generated.

I'd say that the behaviour should be the same for both cases.

My (probably naïve) suggestion would be to change the following code:

https://github.com/divio/djangocms-link/blob/fbb67410377c953ff1e153a91e5306080b2a46fa/djangocms_link/models.py#L150-L153

Instead of overriding ref_page with the current site, I think it should be retrieved from the self.internal_link property, and cms_page_site_id should be retrieved from the current site. That way a meaningful comparison can be made and it can be decided whether the domain prefix is necessary.

[FinalAngel]

@jasper-flux I tried to understand the problems you are experiencing and created a PR with various tests:

#171

The issue originates from:

cms_page = self.placeholder.page if self.placeholder_id else None

Static placeholders act different than regular placeholder and thus self.placeholder.page is not available resulting in the reformatting of the link through:

if ref_page_site_id != cms_page_site_id:

by passing through:

else:
    ref_page = Site.objects.get_current()
    ref_page_site_id = ref_page.pk
    cms_page_site_id = None

This is a bit tricky to figure out as the else is designed to adapt links if there is no placeholder attached as a fallback. There'd need to be an additional conditional statement checking for the static_placeholder's page itself.

@czpython would you have any advice on how to get the page from a static placeholder?