+
+ @transaction.commit_on_success
+ def prepend_history(self, other):
+ """Takes over the the other document's history and prepends to own."""
+
+ assert self != other
+ other_revs = other.change_set.all().count()
+ self.change_set.all().update(revision=models.F('revision') + other_revs)
+ other.change_set.all().update(tree=self)
+ assert not other.change_set.exists()
+ other.delete()