/// Is this vertex of zero length?
    pub fn is_empty(&self) -> bool {
        self.end == self.start
    }

        .any(|e| e.flag.contains(EdgeFlags::BLOCK) || e.flag.contains(EdgeFlags::FOLDER))

        .any(|e| e.flag.contains(EdgeFlags::BLOCK))

            flag: EdgeFlags::empty(),

            flag: EdgeFlags::BLOCK,

                    }
                }
                Some(Record::SolveOrderConflict { change: c, local }) => {
                    // If the last record solved a conflict, replace
                    // the empty "solving" line with this change.
                    if change.up_context.len() == 1 && change.up_context[0].change.is_none() {
                        if let Atom::NewVertex(mut c) = c {
                            c.down_context.extend(change.down_context.into_iter());
                            c.start = change.start;
                            c.end = change.end;
                            self.rec.actions.push(Record::SolveOrderConflict {
                                change: Atom::NewVertex(c),
                                local,
                            });
                            return Ok(());
                        }
                    } else {
                        self.rec
                            .actions
                            .push(Record::SolveOrderConflict { change: c, local })

        put_graph_with_rev(txn, channel, n.flag | EdgeFlags::BLOCK, up, vertex, change)?;

        let flag = if !vertex.is_empty() {
            n.flag | EdgeFlags::BLOCK
        } else {
            n.flag - EdgeFlags::BLOCK
        };
        put_graph_with_rev(txn, channel, flag, up, vertex, change)?;