I was mistaken. Lemmy only detected automatically the link when title, body and external reference where the same. It did not do it when the title and body was the same on posts without external references.
First case
https://jlai.lu/post/13228928
https://jlai.lu/post/13228821
Second case
https://jlai.lu/post/13228938
https://jlai.lu/post/13228935
If I remember correctly, Lemmy matches two posts with the exact same title. I think I don’t it by mistake once. Maybe Piefed do the same, maybe it is implemented differently.
Let me check.
So… I made sure to federate !forumlibre@jlai.lu to feddit.online. I joined it then done the same test : A crosspost from Lemmy to Lemmy with no external reference but a text body and still no crosspost is picked up by Piefed
https://feddit.online/post/166043
Here is another 4-days old post, this time with an external ressource crossposted from Lemmy to Piefed.
It gets picked up as crosspost by Lemmy but unfortunatly not by Piefed
https://feddit.online/post/165962
Watching it from Piefed, I have no way to see that it match a post in another community as it doesn’t even refer to the original post using hyperlink.
Then I tried to crosspost it from Lemmy to Piefed using the link of the image and got an error. But many parameter could be the cause. I’ll try again.
Here is a 4-days old post that I just crosspost from and to Lemmy
https://feddit.online/post/165936
It is not pickup as crosspost either.
Interesting. Let me try again with posts with closer dates.
Do I need to use the URL of the picture or of the post itself to crosspost it successfully on Piefed?
Unfortunatly, no :-(
A cross-post is just a post that links to the same URL as another post.
I have to disagree with you. When I crosspost properly, I got the list of each community in which the post is found. I can also open the post in each community in my instance with a simple click.
I vaguely remember reading that PieFed promised that cross-posts will have a single comment space but it seems we are not there yet. I tried what you told me but I could get crosspost. I just have posts referencing one another with a hyperlink.
Too bad
Hi! Pseudo here, back with my Piefed account. I just realised you have access to Guppe groupe from the twittoverse with Piefed. Many there is something to look here about have FB-style group and FB-style pages.
But I don’t now much about FB or ActivityPub to be sure.
Maybe that’s how Lemmy detects crossposting but there is a visual mark of the crosspost in the interface and I have access to a link to the post in the other community that opens in my instance rather than in another instance. That is something very practical that make Lemmy crossposts more than posts with similar content. And that is something I didn’t find in Piefed.