fix(map): the day route waits out a busy router instead of keeping straight lines

The public OSRM hosts answer 429 above about one request a second. The trip
overview and the road trip waited that out and asked again; the day route
took the first refusal as final and drew straight lines between the stops
until the next edit, which is what a day with a change of mode or a quick
switch between days ran into. Both the day route and the overview now go
through one retry helper: a rate limit is waited out, as long as the host
asks when it says, and a refusal the host meant still ends at once.

client/src/components/Map/routeRetry.test.ts

@@ -0,0 +1,85 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { calculateRouteWithLegs, RoutingRefusedError } from './RouteCalculator';
+import { calculateRouteWithRetries, ROUTE_RETRY_DELAYS_MS } from './routeRetry';
+
+vi.mock('./RouteCalculator', async (importActual) => {
+  const actual = await importActual<typeof import('./RouteCalculator')>();
+  return { ...actual, calculateRouteWithLegs: vi.fn() };
+});
+
+const WAYPOINTS = [
+  { lat: 47.5, lng: 19.04 },
+  { lat: 47.49, lng: 19.05 },
+];
+const ROUTED = {
+  coordinates: [
+    [47.5, 19.04],
+    [47.49, 19.05],
+  ],
+  legs: [],
+} as unknown as Awaited<ReturnType<typeof calculateRouteWithLegs>>;
+
+beforeEach(() => {
+  vi.useFakeTimers();
+  vi.mocked(calculateRouteWithLegs).mockReset();
+});
+afterEach(() => vi.useRealTimers());
+
+describe('calculateRouteWithRetries', () => {
+  it('waits out a rate limit and answers with the road (Discord, 16.10.2026)', async () => {
+    vi.mocked(calculateRouteWithLegs)
+      .mockRejectedValueOnce(new RoutingRefusedError(429, null))
+      .mockResolvedValueOnce(ROUTED);
+
+    const answer = calculateRouteWithRetries(WAYPOINTS, { profile: 'driving' });
+    await vi.advanceTimersByTimeAsync(ROUTE_RETRY_DELAYS_MS[0]);
+
+    await expect(answer).resolves.toBe(ROUTED);
+    expect(calculateRouteWithLegs).toHaveBeenCalledTimes(2);
+  });
+
+  it('waits as long as the host asks when that is longer', async () => {
+    vi.mocked(calculateRouteWithLegs)
+      .mockRejectedValueOnce(new RoutingRefusedError(503, 3000))
+      .mockResolvedValueOnce(ROUTED);
+
+    const answer = calculateRouteWithRetries(WAYPOINTS, {});
+    await vi.advanceTimersByTimeAsync(ROUTE_RETRY_DELAYS_MS[0]);
+    expect(calculateRouteWithLegs).toHaveBeenCalledTimes(1);
+    await vi.advanceTimersByTimeAsync(3000 - ROUTE_RETRY_DELAYS_MS[0]);
+
+    await expect(answer).resolves.toBe(ROUTED);
+  });
+
+  it('gives up after the last delay and throws the refusal', async () => {
+    vi.mocked(calculateRouteWithLegs).mockRejectedValue(new RoutingRefusedError(429, null));
+
+    const answer = calculateRouteWithRetries(WAYPOINTS, {});
+    const settled = expect(answer).rejects.toBeInstanceOf(RoutingRefusedError);
+    for (const ms of ROUTE_RETRY_DELAYS_MS) await vi.advanceTimersByTimeAsync(ms);
+
+    await settled;
+    expect(calculateRouteWithLegs).toHaveBeenCalledTimes(ROUTE_RETRY_DELAYS_MS.length + 1);
+  });
+
+  it('throws a refusal the host meant at once', async () => {
+    vi.mocked(calculateRouteWithLegs).mockRejectedValue(new RoutingRefusedError(400, null));
+
+    await expect(calculateRouteWithRetries(WAYPOINTS, {})).rejects.toBeInstanceOf(RoutingRefusedError);
+    expect(calculateRouteWithLegs).toHaveBeenCalledTimes(1);
+  });
+
+  it('stops waiting when the day changes', async () => {
+    const controller = new AbortController();
+    vi.mocked(calculateRouteWithLegs)
+      .mockRejectedValueOnce(new RoutingRefusedError(429, null))
+      .mockRejectedValueOnce(new DOMException('aborted', 'AbortError'));
+
+    const answer = calculateRouteWithRetries(WAYPOINTS, { signal: controller.signal });
+    const settled = expect(answer).rejects.toMatchObject({ name: 'AbortError' });
+    await vi.advanceTimersByTimeAsync(10);
+    controller.abort();
+
+    await settled;
+  });
+});

client/src/components/Map/routeRetry.ts

@@ -0,0 +1,48 @@
+import { calculateRouteWithLegs, RoutingRefusedError } from './RouteCalculator';
+
+// The profile a caller hands in, so a hook routing through here needs nothing else from Map/.
+export type { RouteProfileKey } from './RouteCalculator';
+
+/** How often a rate-limited route is asked for again, and how long after. */
+export const ROUTE_RETRY_DELAYS_MS = [1500, 4000];
+
+/** A pause that ends early, without throwing, when the signal aborts. */
+export const sleepUnlessAborted = (ms: number, signal?: AbortSignal): Promise<void> =>
+  new Promise((resolve) => {
+    if (signal?.aborted || ms <= 0) {
+      resolve();
+      return;
+    }
+    const timer = setTimeout(done, ms);
+    function done(): void {
+      clearTimeout(timer);
+      signal?.removeEventListener('abort', done);
+      resolve();
+    }
+    signal?.addEventListener('abort', done, { once: true });
+  });
+
+/**
+ * `calculateRouteWithLegs`, asked again while the host says it is busy.
+ *
+ * The public OSRM hosts allow about one request a second and answer 429 above that. A
+ * day with a change of mode, or a quick switch between days, asks more often than that,
+ * and the day route used to give up on the first refusal and keep its straight lines
+ * until the next edit (reported on Discord, 16.10.2026). A rate limit is waited out, for
+ * as long as the host asks when it says; a refusal the host meant is thrown at once,
+ * because the same request earns the same answer. An abort ends the wait, and the next
+ * attempt then throws the AbortError the caller already handles.
+ */
+export async function calculateRouteWithRetries(
+  ...[waypoints, opts]: Parameters<typeof calculateRouteWithLegs>
+): ReturnType<typeof calculateRouteWithLegs> {
+  for (let attempt = 0; ; attempt++) {
+    try {
+      return await calculateRouteWithLegs(waypoints, opts);
+    } catch (err) {
+      const rateLimit = err instanceof RoutingRefusedError && err.isRateLimit ? err : null;
+      if (!rateLimit || attempt >= ROUTE_RETRY_DELAYS_MS.length || opts?.signal?.aborted) throw err;
+      await sleepUnlessAborted(Math.max(ROUTE_RETRY_DELAYS_MS[attempt], rateLimit.retryAfterMs ?? 0), opts?.signal);
+    }
+  }
+}

client/src/components/Map/tripRouteGeometry.ts

@@ -1,4 +1,5 @@
-import { calculateRouteWithLegs, RoutingRefusedError, type RouteProfileKey } from './RouteCalculator'
+import type { RouteProfileKey } from './RouteCalculator'
+import { calculateRouteWithRetries, sleepUnlessAborted as sleep } from './routeRetry'
 import { buildDayRouteRuns, type DayRouteInputs, type DayRoutePoint } from './dayRoutePlan'
 import { dayViaLookup, foldViaLegs, threadVias, viasOnDayLeg, type DayViaLookup } from '../../utils/dayRouteVias'
 import { projectDayItinerary } from './dayTourProjection'
@@ -185,20 +186,6 @@ export function summariseTripRoute(days: TripOverviewDay[]): TripRouteSummary {
 const REQUEST_SPACING_MS = 1100
 /** Anything answered faster than this came out of RouteCalculator's cache, not the network. */
 const CACHE_HIT_MS = 60
-/** How often a rate-limited leg is tried again, and how long after. */
-const RETRY_DELAYS_MS = [1500, 4000]
-
-const sleep = (ms: number, signal?: AbortSignal): Promise<void> =>
-  new Promise(resolve => {
-    if (signal?.aborted || ms <= 0) { resolve(); return }
-    const timer = setTimeout(done, ms)
-    function done(): void {
-      clearTimeout(timer)
-      signal?.removeEventListener('abort', done)
-      resolve()
-    }
-    signal?.addEventListener('abort', done, { once: true })
-  })
 
 /**
  * Ask the router for every leg of every day, one at a time.
@@ -233,23 +220,16 @@ export async function routeTripLegs(
     runs.forEach((chunks, r) => {
       chunks.forEach((chunk, c) => {
         tasks.push(async () => {
-          for (let attempt = 0; attempt <= RETRY_DELAYS_MS.length; attempt++) {
-            if (signal?.aborted) return
-            try {
-              const answer = await calculateRouteWithLegs(
-                chunk.waypoints,
-                { signal, profile: chunk.mode, tripId, dayId: day.id },
-              )
-              routed[d][r][c] = { coordinates: answer.coordinates, legs: foldViaLegs(answer.legs, chunk.stopAt, unit) }
-              onAnswer?.(routed)
-              return
-            } catch (err) {
-              if (signal?.aborted) return
-              const rateLimit = err instanceof RoutingRefusedError && err.isRateLimit ? err : null
-              if (!rateLimit || attempt === RETRY_DELAYS_MS.length) return
-              // When the host says how long to wait, waiting less is just a second refusal.
-              await sleep(Math.max(RETRY_DELAYS_MS[attempt], rateLimit.retryAfterMs ?? 0), signal)
-            }
+          if (signal?.aborted) return
+          try {
+            const answer = await calculateRouteWithRetries(
+              chunk.waypoints,
+              { signal, profile: chunk.mode, tripId, dayId: day.id },
+            )
+            routed[d][r][c] = { coordinates: answer.coordinates, legs: foldViaLegs(answer.legs, chunk.stopAt, unit) }
+            onAnswer?.(routed)
+          } catch {
+            // Refused for good, or aborted: the leg keeps its straight line.
           }
         })
       })

client/src/hooks/useRouteCalculation.ts

@@ -4,7 +4,7 @@ import { useState, useCallback, useRef, useEffect, useMemo } from 'react'
 import { useTripStore } from '../store/tripStore'
 import { useSettingsStore } from '../store/settingsStore'
 import { useAddonStore } from '../store/addonStore'
-import { calculateRouteWithLegs, type RouteProfileKey } from '../components/Map/RouteCalculator'
+import { calculateRouteWithRetries, type RouteProfileKey } from '../components/Map/routeRetry'
 import { buildDayRouteRuns, hotelBookendOf, TRANSPORT_TYPES } from '../components/Map/dayRoutePlan'
 import { dayViaLookup, foldViaLegs, threadVias, viaKeyOf, viasOnDayLeg } from '../utils/dayRouteVias'
 import { resolveLegMode } from '../components/Planner/legMode'
@@ -131,7 +131,8 @@ export function useRouteCalculation(tripStore: Pick<TripStoreState, 'assignments
           const straight = (): [number, number][] => chunk.map(p => [p.lat, p.lng] as [number, number])
           const { waypoints, stopAt } = threadVias(chunk, (from, to) => viasOnDayLeg(viaLookup, dayId, mode, from, to))
           try {
-            const r = await calculateRouteWithLegs(waypoints, { signal: controller.signal, profile: mode, tripId, dayId })
+            // A busy router is waited out rather than left as straight lines until the next edit.
+            const r = await calculateRouteWithRetries(waypoints, { signal: controller.signal, profile: mode, tripId, dayId })
             pushCoords(r.coordinates.length >= 2 ? r.coordinates : straight(), mode === 'walking')
             // Leg k runs from chunk[k] to chunk[k + 1]; a hotel bookend says so on the
             // segment, which is how the phone timeline finds it (#2501).