v0.4.9h — a leg that is part of the row, the deck the sheet prints, and regions not miles per hour

The 0.4.9 line's port of v0.7.2, minus Gitea#18: the Division map redraw is a
multiplayer redesign and does not belong in a build people are mid-playtest on.

Gitea#17 — a 45° leg is an end of the west-to-east row, so backing into a cut
through a curve's south leg no longer couples it back to front, and a crew
pulling out through a leg takes its own cut with it.

Gitea#14 — every count is docs/Deck cards5.xlsx, including removing the Q12
office doubling and the Gap 12 industry tripling.

Gitea#15 — RAR reversed it: the placement is legal; what must hold is that no
train crosses the gap.

Gitea#3 — the printed speeds are scenery. One Stage per printed region, and
where a train starts is what varies.

test/cut-ordering.test.ts

@@ -13,7 +13,7 @@ import assert from 'node:assert/strict';
 
 import { applyIntent, areaOf, check } from '../src/engine/apply.ts';
 import { createGame } from '../src/engine/setup.ts';
-import type { CrewTray, GameConfig, GameState, GridCoord, RollingStock, TrackCard } from '../src/engine/state.ts';
+import type { CrewTray, GameConfig, GameState, GridCoord, RollingStock, TrackArc, TrackCard } from '../src/engine/state.ts';
 import { carsOn, coordKey, turnOf } from '../src/engine/state.ts';
 
 const config: GameConfig = {
@@ -51,12 +51,18 @@ function row(s: GameState, n: number): void {
   for (let c = 0; c < n; c++) addCard(s, at(1, c), straight());
 }
 
+/**
+ * `facing` is the PORT the engine points out through, which is not always an east-west one: a train
+ * standing on a curve points along its 45° leg. `railFacing` carries the east-west sense the train
+ * arrived with, so it keeps a straight answer whatever port the nose is on (`railFacingOf`).
+ */
 function placeTray(
   s: GameState,
   coord: GridCoord,
   consist: RollingStock[],
-  facing: 'e' | 'w',
+  facing: 'n' | 's' | 'e' | 'w',
   engineAt = 0,
+  railFacing: 'e' | 'w' = facing === 'w' ? 'w' : 'e',
 ): string {
   const id = s.freeTrays.pop()!;
   s.trays.set(id, {
@@ -65,9 +71,9 @@ function placeTray(
     trainIsExtra: false,
     engineAt,
     consist,
-    direction: facing === 'w' ? 'west' : 'east',
+    direction: railFacing === 'w' ? 'west' : 'east',
     facing,
-    railFacing: facing,
+    railFacing,
     position: { at: 'grid', seat: 0, coord },
     movesUsed: 0,
   } as CrewTray);
@@ -371,3 +377,85 @@ describe('taking your own cut back is undoing the drop, not a fresh pick-up', ()
     );
   });
 });
+
+// ---------------------------------------------------------------------------
+
+describe('a 45° leg is part of the west-to-east row, not outside it (Gitea#17)', () => {
+  /**
+   * Reported: "Cars were West to East Caboose, Loaded boxcar, Loaded boxcar, Loaded boxcar. After
+   * backing into that square cars were attached to the train Loaded boxcar, Loaded boxcar, Loaded
+   * boxcar, Caboose, Engine." The caboose came back next to the engine instead of at the far end,
+   * which also leaves the train badly made up under §8.2.
+   *
+   * The square was a `sw` CURVE and the train backed in through its SOUTH leg. `standing` runs west
+   * to east, and the two places that walk it both asked the PORT which end of the row they were at:
+   * `exploreMoves` reversed the row for an 'e' entry and for nothing else, and `cutTowards` answered
+   * "you meet nothing" for a north or south exit. Neither is a property of the port.
+   *
+   * A 45° leg leaves through the MIDDLE of its edge, so its end of the run is whichever end the arc
+   * does not reach: the south leg of a `sw` curve is the row's EAST end, and the south leg of an
+   * `se` curve is its WEST end. Same port, opposite answers — which is why `rowEndAt` has to ask the
+   * card.
+   */
+  const curve = (arc: TrackArc, standing: RollingStock[] = [], standingWest = 0): TrackCard => ({
+    geometry: { kind: 'track', geometry: 'curved', arc, hand: 'right' },
+    baseOperationalRail: true,
+    standing,
+    standingWest,
+    facility: null,
+    modifiers: [],
+    enhancements: [],
+  });
+
+  /**
+   * The reported board, minimally: a `sw` curve holding the cut, and an `ne` curve below it for the
+   * train to run from. Both legs lie on the `ne_sw` diagonal, so the two cards actually join.
+   */
+  function board(standing: RollingStock[], standingWest = standing.length): GameState {
+    const s = game();
+    addCard(s, at(1, 0), curve('sw', standing, standingWest));
+    addCard(s, at(0, 0), curve('ne'));
+    switching(s);
+    return s;
+  }
+
+  it('backs into a cut through the south leg and meets the EAST end of the row first', () => {
+    const s = board([car('caboose', true), car('boxcar', true), car('boxcar', true), car('boxcar', true)]);
+    // Facing east on the `ne` curve, so reversing pulls out through its north leg and into the
+    // curve above through that card's south leg — the move in the reported save.
+    const id = placeTray(s, at(0, 0), [], 'e');
+    const r = applyIntent(s, 0, { type: 'switch.move', trayId: id, to: at(1, 0), reverse: true });
+    assert.ok(r.ok, `the reverse move was refused: ${r.ok ? '' : r.code}`);
+    // Coupled behind the engine nearest-car-first, and the nearest car is the one at the south end
+    // — the LAST of a west-to-east row on a `sw` curve. The caboose was westmost, so it ends up
+    // furthest from the engine, which is where §8.2 needs it.
+    assert.deepEqual(types(s.trays.get(id)!.consist), ['boxcar', 'boxcar', 'boxcar', 'caboose']);
+  });
+
+  it('meets the WEST end of the row first where the same leg belongs to an `se` curve', () => {
+    // The mirror, and the reason the port alone cannot answer: an `se` curve's south leg is the
+    // west end of its row, so the same reverse move meets the caboose first.
+    const s = game();
+    addCard(s, at(1, 0), curve('se', [car('caboose', true), car('boxcar', true)], 2));
+    addCard(s, at(0, 0), curve('nw'));
+    switching(s);
+    const id = placeTray(s, at(0, 0), [], 'w');
+    const r = applyIntent(s, 0, { type: 'switch.move', trayId: id, to: at(1, 0), reverse: true });
+    assert.ok(r.ok, `the reverse move was refused: ${r.ok ? '' : r.code}`);
+    assert.deepEqual(types(s.trays.get(id)!.consist), ['caboose', 'boxcar']);
+  });
+
+  it('takes its own cut back with it when it pulls out through the south leg (§A.4)', () => {
+    // The other half of the same assumption: `cutTowards` said a train leaving north or south meets
+    // nothing, so a crew standing on a curve drove away and left the cars beside it standing —
+    // exactly what mandatory coupling forbids.
+    const s = board([car('boxcar', true)], 0);
+    // `standingWest` 0 puts the boxcar EAST of the train, which on a `sw` curve is between it and
+    // the south leg it is about to leave by.
+    const id = placeTray(s, at(1, 0), [], 's');
+    const r = applyIntent(s, 0, { type: 'switch.move', trayId: id, to: at(0, 0), reverse: false });
+    assert.ok(r.ok, `the move off the curve was refused: ${r.ok ? '' : r.code}`);
+    assert.deepEqual(types(s.trays.get(id)!.consist), ['boxcar'], 'the cut beside the train was left standing');
+    assert.deepEqual(standingAt(s, at(1, 0)), [], 'the cars should have come off the card');
+  });
+});