edge walk failed

[xuruiray]

valhalla/src/thor/route_matcher.cc

Lines 132 to 143 in 1b864c9

	uint32_t level = node.level();
	uint32_t start_de = followed_edges[correlated_index][level].first;
	// Iterate through directed edges from this node
	const NodeInfo* nodeinfo = tile->node(node);
	GraphId edge_id(node.tileid(), level, nodeinfo->edge_index());
	const DirectedEdge* de = tile->directededge(nodeinfo->edge_index());
	for (uint32_t i = start_de; i < nodeinfo->edge_count(); i++, de++, ++edge_id) {
	// Mark the directed edge as already followed
	followed_edges[correlated_index][level].first = i;
	// Skip shortcuts and transit connection edges

why do we need followed_edges ？ I feel like this is a useless cache, use start_de will skip some edge from the current node

There's a scenario.
when we get the wrong path and try to step back, it is the same correlated_index but not the same node (because there are two very similar edges)
if use start_de from followed_edges will skip some edge