invalid turn type returned

[karenzshea]

A request in New Zealand (extract can be fetched from geofabrik), I see a turn type that shouldn't be exposed:

$ curl 'localhost:5000/route/v1/car/171.21113,-42.450158;171.12712383270264,-42.58207906066402?steps=true' | jq '.routes[].legs[].steps[].maneuver.type'

Returns,

"depart"
"exit roundabout"
"invalid"
"exit rotary"
"arrive"

In debug mode, this assertion is triggered which assumes that for a step to be collapsed into the one before it, the geometry indices of the two steps should be adjacent.

I managed to narrow down a possible cause for this in the segregated intersection collapsing, so that when I comment out the segregated intersection collapsing in route_api and rerun the same request, I see these turn types emitted

"depart"
"exit roundabout"
"new name"
"new name"
"new name"
"rotary"
"exit rotary"
"arrive"

Inspecting this route though, I'm not sure what should be considered a segregated intersection,
https://gist.github.com/karenzshea/8ff491dbe7155fc8a94cb7701ab2aa89

Next steps

• Determine which parts of the code are incorrectly collapsing steps
• Is an intersection getting misclassified as segregated?
• Write a test case
• Fix either invalid turn type emission, or segregated intersection misclassification

cc @dgearhart