Unless I'm misunderstanding something, the publish service callback
imposeSortOrderOnPublishedCollection() isn't called when images are rearranged in a publish collection. This callback is only invoked if something else triggers a republish, i.e., marking an image to be republished or changing metadata of an image. Then the imposeSortOrderOnPublishedCollection() callback is invoked after the changed image is processRenderedPhotos() callback finishes. This issue is aggravated because the LR UI shows the images in the new sort order but there is no indication this change needs to be published causing a disconnect between LR and the publish service.
If there is some SDK call or listener that I should be using to monitor the sort changes, I'm not aware of it nor can I find it in the SDK docs.
It would be nice to trigger a user dialog or some other notification a little while after the images have been rearranged asking if the changes should be pushed to the publish service.
The publish service callback imposeSortOrderOnPublishedCollection() is how the plugin is notified the sort order has changed (assuming the publish service set 'supportsCustomSortOrder' to true. My issue isn't that the plugin isn't being notified of the sort order change. My issue is when/how the plugin is notified. The imposeSortOrderonPublishedCollection() callback isn't called unless there is something else to publish/republish. One of the parameters passed to that callback is:
"3. remoteIdSequence(array of string or number) The IDs for each published photo that was stored via exportRendition:recordPublishedPhotoId"
So the order presented to the user and the order on the publish service can diverge without any notification to the user.
I wanted to confirm I wasn't missing something before posting as a feature request