Its been a while since I implemented this (hopefully its all here). Copy from one history to another.
I'm currently working on merging this pull request. Can you update to the latest default revision and re-apply this change in your repository?
I have updated this to work with the new source, content structure in history_contents.py.
Don't know if there is something more modern than
assert trans.user.id == hda.history.user_id, "HistoryDatasetAssocation does not belong to current user"
like 'check_ownership' for hda = self.get_dataset(trans, content)
Thanks for the update and the work, Andrew. Merged.