fix(traffic): pass fetchFlowDetail through the layer's source slot

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/data/traffic.js

@@ -9,9 +9,18 @@ const sourceSlot = createSourceSlot(
   {
     getFlowSessionStats: () => ({ tilesFetched: 0 }),
     resetFlowTileCache: () => {},
+    // The layer reads stale cached tiles through this; a source without it
+    // answers with fresh segments only.
+    fetchFlowDetail: async (...args) => ({
+      segments: await sourceSlot.source.fetchFlowForBounds(...args),
+      stale: false,
+      oldestTileAt: null,
+    }),
   },
 );
 export const configureTrafficSource = sourceSlot.configure;
+/** The source the traffic layer reads, as configured. */
+export const trafficSource = sourceSlot.source;
 const layer = createApplicationTraffic({
   source: sourceSlot.source,
 });

src/data/traffic.test.mjs

@@ -22,7 +22,10 @@ import { DataLayerManager, layerFeedState } from './manager.js';
 const LIVE_CLAIM = /\bLIVE\b|\bGPS\b|\breal[- ]?time\b/;
 
 test('a superseded flow fetch is not an outage', () => {
-  assert.equal(deriveTrafficFlowError({ name: 'AbortError', message: 'aborted' }), null);
+  assert.equal(
+    deriveTrafficFlowError({ name: 'AbortError', message: 'aborted' }),
+    null,
+  );
   assert.equal(deriveTrafficFlowError(null), null);
   assert.equal(deriveTrafficFlowError(undefined), null);
 });
@@ -30,10 +33,22 @@ test('a superseded flow fetch is not an outage', () => {
 test('flow failures map onto short, specific reasons', () => {
   const reason = (message) => deriveTrafficFlowError(new Error(message));
   assert.equal(reason('flow tile 12/1/1: HTTP 503'), 'TomTom key unavailable');
-  assert.equal(reason('flow tile 12/1/1: HTTP 429'), 'TomTom daily budget reached');
+  assert.equal(
-  assert.equal(reason('flow tile 12/1/1: HTTP 502'), 'TomTom upstream unreachable');
+    reason('flow tile 12/1/1: HTTP 429'),
-  assert.equal(reason('flow tile 12/1/1: HTTP 504'), 'TomTom upstream unreachable');
+    'TomTom daily budget reached',
-  assert.equal(reason('flow tile 12/1/1: HTTP 418'), 'TomTom flow error (HTTP 418)');
+  );
+  assert.equal(
+    reason('flow tile 12/1/1: HTTP 502'),
+    'TomTom upstream unreachable',
+  );
+  assert.equal(
+    reason('flow tile 12/1/1: HTTP 504'),
+    'TomTom upstream unreachable',
+  );
+  assert.equal(
+    reason('flow tile 12/1/1: HTTP 418'),
+    'TomTom flow error (HTTP 418)',
+  );
   assert.equal(reason('flow fetch failed'), 'TomTom flow unavailable');
 });
 
@@ -56,19 +71,32 @@ test('no keyless label ever implies a live feed', () => {
     trafficFeedPresentation({ liveMode: false, fetching: false }),
     trafficFeedPresentation({ liveMode: false, fetching: true }),
     trafficFeedPresentation({ statusUnavailable: true }),
-    trafficFeedPresentation({ liveMode: true, flowError: 'TomTom flow unavailable' }),
+    trafficFeedPresentation({
-    trafficFeedPresentation({ liveMode: true, fetching: true, flowError: 'TomTom flow unavailable' }),
+      liveMode: true,
+      flowError: 'TomTom flow unavailable',
+    }),
+    trafficFeedPresentation({
+      liveMode: true,
+      fetching: true,
+      flowError: 'TomTom flow unavailable',
+    }),
   ].map((feed) => feed.loadingLabel);
   for (const label of labels) {
     assert.ok(!LIVE_CLAIM.test(label), `label implies live data: ${label}`);
-    assert.ok(label.startsWith('SIMULATED'), `fallback label must lead with the mode: ${label}`);
+    assert.ok(
+      label.startsWith('SIMULATED'),
+      `fallback label must lead with the mode: ${label}`,
+    );
   }
 });
 
 test('simulating because the status probe failed reads differently from keyless by design', () => {
   const probeDown = trafficFeedPresentation({ statusUnavailable: true });
   assert.equal(probeDown.mode, 'sim');
-  assert.equal(probeDown.loadingLabel, 'SIMULATED — traffic service unreachable');
+  assert.equal(
+    probeDown.loadingLabel,
+    'SIMULATED — traffic service unreachable',
+  );
 });
 
 test('a healthy keyed layer reports live flow with its real coverage', () => {
@@ -76,7 +104,8 @@ test('a healthy keyed layer reports live flow with its real coverage', () => {
   assert.deepEqual(idle, {
     mode: 'live',
     error: null,
-    loadingLabel: 'LIVE · Roads: OpenStreetMap · Flow: TomTom · 87% cov · Unmatched: simulated',
+    loadingLabel:
+      'LIVE · Roads: OpenStreetMap · Flow: TomTom · 87% cov · Unmatched: simulated',
   });
   assert.equal(
     trafficFeedPresentation({ liveMode: true, fetching: true }).loadingLabel,
@@ -100,7 +129,11 @@ test('a mid-session flow outage degrades instead of reporting stale live coverag
     fetching: true,
     flowError: 'TomTom daily budget reached',
   });
-  assert.deepEqual(busy, down, 'the degraded state reads the same whether or not a load is in flight');
+  assert.deepEqual(
+    busy,
+    down,
+    'the degraded state reads the same whether or not a load is in flight',
+  );
 });
 
 test('the rendered steady-state meta line carries the SIMULATED copy', () => {
@@ -116,10 +149,12 @@ test('the rendered steady-state meta line carries the SIMULATED copy', () => {
   assert.equal(
     mgr._buildMetaText({
       source: 'OpenStreetMap',
-      stats: stats(trafficFeedPresentation({
+      stats: stats(
+        trafficFeedPresentation({
           liveMode: true,
           flowError: 'TomTom daily budget reached',
-      })),
+        }),
+      ),
     }),
     'DEGRADED · OpenStreetMap · SIMULATED — TomTom daily budget reached',
   );
@@ -128,17 +163,26 @@ test('the rendered steady-state meta line carries the SIMULATED copy', () => {
 test('the manager reads keyless as FALLBACK and an outage as DEGRADED', () => {
   const settled = { count: 4200, lastUpdate: Date.now() };
   assert.equal(
-    layerFeedState({ ...settled, ...trafficFeedPresentation({ liveMode: false }) }),
+    layerFeedState({
+      ...settled,
+      ...trafficFeedPresentation({ liveMode: false }),
+    }),
     'fallback',
   );
   assert.equal(
-    layerFeedState({ ...settled, ...trafficFeedPresentation({ liveMode: true }) }),
+    layerFeedState({
+      ...settled,
+      ...trafficFeedPresentation({ liveMode: true }),
+    }),
     'nominal',
   );
   assert.equal(
     layerFeedState({
       ...settled,
-      ...trafficFeedPresentation({ liveMode: true, flowError: 'TomTom flow unavailable' }),
+      ...trafficFeedPresentation({
+        liveMode: true,
+        flowError: 'TomTom flow unavailable',
+      }),
     }),
     'degraded',
   );
@@ -148,7 +192,10 @@ test('the shipped layer boots keyless-honest before any status check', () => {
   const stats = trafficLayer.getStats();
   assert.equal(stats.mode, 'sim');
   assert.equal(stats.error, null);
-  assert.ok(!LIVE_CLAIM.test(stats.loadingLabel), `boot label implies live data: ${stats.loadingLabel}`);
+  assert.ok(
+    !LIVE_CLAIM.test(stats.loadingLabel),
+    `boot label implies live data: ${stats.loadingLabel}`,
+  );
   assert.equal(layerFeedState(stats), 'fallback');
 });
 
@@ -167,3 +214,42 @@ test('zero matched dots never claims live coverage', () => {
   assert.match(feed.loadingLabel, /TomTom \(no matches\)/);
   assert.ok(!LIVE_CLAIM.test(feed.loadingLabel));
 });
+
+test('the traffic layer source passes fetchFlowDetail through, so stale tiles reach the layer', async () => {
+  const { trafficSource, configureTrafficSource } =
+    await import('./traffic.js');
+  assert.equal(typeof trafficSource.fetchFlowDetail, 'function');
+  const base = {
+    requestRoads: async () => ({}),
+    getStatus: async () => ({}),
+    fetchFlowForBounds: async () => ['segment'],
+  };
+  let release = configureTrafficSource({
+    ...base,
+    fetchFlowDetail: async () => ({
+      segments: ['segment'],
+      stale: true,
+      oldestTileAt: 1000,
+    }),
+  });
+  try {
+    assert.deepEqual(await trafficSource.fetchFlowDetail({}), {
+      segments: ['segment'],
+      stale: true,
+      oldestTileAt: 1000,
+    });
+  } finally {
+    release();
+  }
+  // A source without fetchFlowDetail answers with fresh segments.
+  release = configureTrafficSource(base);
+  try {
+    assert.deepEqual(await trafficSource.fetchFlowDetail({}), {
+      segments: ['segment'],
+      stale: false,
+      oldestTileAt: null,
+    });
+  } finally {
+    release();
+  }
+});