FA-12218 / Navigation route constraints / Member archive

Roundabout instructions count entrances as exits · case 03

Roundabout instructions count entrances as exits in the controlled route-policy fixture.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

Arms are ordered after entry as (ID, may_exit, public). Return one-based legal-exit ordinal for a legal selected arm, or None for an absent or forbidden arm.

Why this case matters

Navigation policies depend on road context that a shortest-path cost alone does not encode.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
entrance excluded	`2`	`1`	Failed

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