Return the ordered points of the shortest track route

[Drefvelin]

What changed

TrackRegistry.shortestRoute(world, ax, az, radiusA, bx, bz, radiusB, spacing) returns a TrackRoute(length, points): the same route shortestRouteLength measures, with points sampled along the track in order from A to B.

• Both queries share one graph and one search. shortestRouteLength keeps its signature and behaviour; its existing tests are untouched.
• Points follow the track in travel order across junctions, against a spline's direction, and across the seam of a loop. The exit of each spline piece is included.
• Spacing follows sampleTrack: invalid values become 4 blocks, with a 0.5 block minimum.
• Areas that overlap on the track give one point and length 0.

SimpleFactions needs this to work out which provinces a railway passes through, in order, for its trade networks.

Testing

mvn verify passes locally: 689 tests, 14 of them new (length equals shortestRouteLength on every existing route fixture, reverse travel, junctions, loop seams, broken segments, overlap, spacing rules).

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📝 Summary

Summary by CodeRabbit

• New Features
  • Added the ability to find the shortest route between two areas of a track and receive ordered points along it.
  • Route points follow the direction of travel and account for junctions, loops and changes in height. The route length is also available.
  • Sampling spacing defaults to 4 blocks when invalid and is limited to a minimum of 0.5 blocks.
  • No route is returned when the areas cannot be connected or the route would cross a broken track segment.

Walkthrough

The track route query now returns an optional route containing its length and sampled points. The registry exposes the query. The search reconstructs directed spline legs, and tests cover route geometry, spacing and route availability.

Changes

Sampled track routes

Layer / File(s)	Summary
Directed route-path reconstruction src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRoute.java, src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQuery.java	The search retains directed spline spans and predecessor edges, then reconstructs route legs and total length.
Route sampling and registry API src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQuery.java, src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRegistry.java	The query samples route legs in A-to-B order. Invalid or non-positive spacing defaults to 4 blocks, and positive spacing is clamped to a minimum of 0.5 blocks. The registry delegates to the query.
Route and sampling validation src/test/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQueryPointsTest.java	Tests cover route availability, length, direction, junctions, loops, broken segments, spacing, immutability and registry delegation.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant TrackRegistry
  participant TrackRouteQuery
  participant Dijkstra
  TrackRegistry->>TrackRouteQuery: shortestRoute request
  TrackRouteQuery->>Dijkstra: find shortest path and predecessor edges
  Dijkstra-->>TrackRouteQuery: path length and directed legs
  TrackRouteQuery-->>TrackRegistry: sampled TrackRoute

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Merge Risk: 🔵 Low · up to 37212

Routes through manually attached, misaligned junctions can report misleading points and length. This is a bounded issue, but junction continuity should be checked before those routes are relied on.

Security Architecture Review

Security architecture risk: 🔵 Low · up to 37212

The new API preserves the existing read-only route-query boundary and returns an immutable result. No new permission bypass or privileged operation was identified. External consumers and their use of the additional geometry remain outside the reviewed scope.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The evidenced exposure expansion is additional track geometry available through an existing plugin-facing registry boundary. The inspected query limits graph membership to the requested world; external consumers' access policies and downstream uses are not established.

Trust Boundaries and Controls

• inferred — The inspected methods perform no caller-identity or permission transition. World filtering selects query data; it is not caller authorization. Any authorization required when exposing this API to untrusted callers must therefore remain with the consuming integration.

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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Actionable comments posted: 1

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Inline comments:
Review comments at
@src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQuery.java:
- Around line 170-174: Update TrackRouteQuery.findRoute’s junction handling to
compare the stem position at wrapped junction.s with the branch position at s=0
before anchoring or linking them. Only create the zero-weight edge when the
ports are continuous; leave mismatched anchors disconnected.

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: Organization UI
• Review profile: CHILL
• Plan: Advanced
• Run ID: 77ec81ac-1d62-49ad-a917-750a724df0c0

📥 Commits

Reviewing files that changed from the base of the PR and between b4bb783 and 372124e.

📒 Files selected for processing (4)

• src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRegistry.java
• src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRoute.java
• src/main/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQuery.java
• src/test/java/net/tfminecraft/vehicleframework/tracks/TrackRouteQueryPointsTest.java

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