+ end
+ # any remaining members must be new additions
+ changed_members += members
+
+ # update the members. first delete all the old members, as the new
+ # members may be in a different order and i don't feel like implementing
+ # a longest common subsequence algorithm to optimise this.
+ members = self.members
+ RelationMember.delete_all(:relation_id => self.id)
+ members.each_with_index do |m,i|
+ mem = RelationMember.new
+ mem.relation_id = self.id
+ mem.sequence_id = i
+ mem.member_type = m[0]
+ mem.member_id = m[1]
+ mem.member_role = m[2]
+ mem.save!
+ end
+
+ old_relation = OldRelation.from_relation(self)
+ old_relation.timestamp = t
+ old_relation.save_with_dependencies!
+
+ # update the bbox of the changeset and save it too.
+ # discussion on the mailing list gave the following definition for
+ # the bounding box update procedure of a relation:
+ #
+ # adding or removing nodes or ways from a relation causes them to be
+ # added to the changeset bounding box. adding a relation member or
+ # changing tag values causes all node and way members to be added to the
+ # bounding box. this is similar to how the map call does things and is
+ # reasonable on the assumption that adding or removing members doesn't
+ # materially change the rest of the relation.
+ any_relations =
+ changed_members.collect { |id,type| type == "relation" }.
+ inject(false) { |b,s| b or s }
+
+ update_members = if tags_changed or any_relations
+ # add all non-relation bounding boxes to the changeset
+ # FIXME: check for tag changes along with element deletions and
+ # make sure that the deleted element's bounding box is hit.
+ self.members
+ else
+ changed_members
+ end
+ update_members.each do |type, id, role|
+ if type != "Relation"
+ update_changeset_element(type, id)