Alexandrite now has cross-posting! You can cross post from the '...' menu on posts:
You then pick a community from your subscriptions, or search for any other community, or directly enter the full name like alexandrite@lemmy.world if you want a very specific one and don't want to bother with searching.
And links to cross-posts will now show when viewing a posts:
Alexandrite now matches Lemmy-UI handling taglines. If an instance has any taglines set it will now pick a random one instead of showing all of them.
Lastly if you have NSFW thumbnail handling set to "Hide" or "Blur", it will now hide/blur thumbnails when a post is in a NSFW community, even if the post itself isn't marked NSFW, as the post is probably actually NSFW anyway and it's better to be safe than sorry.
It’s a relatively common request. Do you think it makes more sense in the front or back end (though it could exist in both I suppose)?
How would the backend handle cross posts to communities not visible or subscribed to on that instance? See such cross posts even possible? Are they even listed?
Lemmy doesn't have that strong of a "concept" of cross posts. The way it appears to work is that all posts linking to the same URL are all considered cross-posts of each other, so I bet the cross posts Lemmy's API gives are basically just search results for that URL. When making a cross post there's nothing that I'm doing to identify that it's a cross post, but it knows.
I'm not sure what'd be best. Backend would maybe be the least taxing, but at any rate the amount of work to be done to gather all the comments goes up as the number of cross-posts increeases, so 8 cross posts means you have to request 8 times the number of comment lists.
Maybe a good middle ground could be a menu that shows you a bit more of the cross post (because you can completely change the post body for example, or just link to the same thing on a brand new post) and let you select which post's comments you'd like to see.
Yea, there's an issue (on GitHub) to show not just cross-posts with the same URL (which only works for posts with a URL in the first place), but also to anytime a cross-post is made, which, along with the idea of being able to view a merge of the comments, seems like a nice idea ... along with things like multi-communities/community-groups, it would facilitate more connectivity and/or user-driven etching out of customisable "spaces".