fix: distinguish partial vessel snapshots from stale data

src/layers/vessels/evidence.js

@@ -25,6 +25,7 @@ export function createEvidence({
     state.feed.loaded = true;
     state.feed.error = null;
     state.feed.stale = false;
+    state.feed.partial = false;
     state.feed.lastUpdate = Date.now();
     state.feed.transportStatus = 'synthetic';
     state.feed.lastMessageAt = null;

src/layers/vessels/ingestion.js

@@ -102,6 +102,7 @@ export function createIngestion({
     feed.lastMessageAt = snapshot.lastMessageAt;
     feed.rawRowCount = snapshot.rawRowCount;
     feed.acceptedRowCount = snapshot.acceptedRowCount;
+    feed.partial = payload?.complete === false;
 
     if (snapshot.acceptedRowCount === 0) {
       feed.count = readCount();
@@ -133,7 +134,8 @@ export function createIngestion({
     feed.count = readCount();
     feed.stale =
       Boolean(payload?.refreshing) ||
-      payload?.complete === false ||
+      payload?.freshness === 'stale' ||
+      snapshot.transportStatus === 'stale' ||
       payload?.freshness === 'unknown';
     feed.newestPositionAt = payload?.newestPositionAt || null;
     // Not unconditionally null: a degraded feed keeps its reason even though the
@@ -190,6 +192,7 @@ export function createVesselFeed() {
     loading: false,
     loaded: false,
     stale: false,
+    partial: false,
     error: null,
     loadingLabel: '',
     lastUpdate: null,

src/layers/vessels/lifecycle.js

@@ -100,6 +100,7 @@ export function createLifecycle({
     state.feed.loading = false;
     state.feed.loaded = false;
     state.feed.stale = false;
+    state.feed.partial = false;
     state.feed.error = null;
     state.feed.loadingLabel = '';
     state.feed.lastUpdate = null;

src/layers/vessels/ownership.test.mjs

@@ -124,7 +124,8 @@ test('partial observations retain missing contacts only until their receipt dead
   current = snapshot([observation('111')], { complete: false, rawRowCount: 2 });
   await layer.update();
   assert.equal(layer.hasContact('222'), true);
-  assert.equal(layer.getStats().stale, true);
+  assert.equal(layer.getStats().stale, false);
+  assert.equal(layer.getStats().partial, true);
   assert.equal(layer.getStats().rawRowCount, 2);
   assert.equal(layer.getStats().acceptedRowCount, 1);
   assert.equal(layer.getStats().lastUpdate, 500);
@@ -301,3 +302,62 @@ test('refresh keeps pick identity and renderer geometry separate, and eviction r
   assert.equal(primitives.has(primitive), false);
   assert.equal(layer.findByQuery('111'), null);
 });
+
+test('partial vessel snapshots preserve freshness and recover after a complete update', async (t) => {
+  const originalDocument = globalThis.document;
+  globalThis.document = { getElementById: () => null };
+  t.after(() => {
+    if (originalDocument === undefined) delete globalThis.document;
+    else globalThis.document = originalDocument;
+  });
+  const { vesselSnapshot } = await import('../../sources/live/vessels.js');
+  const { layerFeedState } = await import('../../data/feedState.js');
+  const valid = {
+    mmsi: '123456789',
+    lat: 51.93,
+    lon: 4.05,
+    last_position_epoch: 1,
+  };
+  let current = vesselSnapshot({
+    rows: [valid, { ...valid }, { mmsi: '987654321', lat: 200, lon: 4 }],
+    status: 'live',
+  });
+  const { layer } = setup({ getSnapshot: async () => current });
+  await layer.update();
+  assert.equal(layer.getStats().partial, true);
+  assert.equal(layer.getStats().stale, false);
+  assert.equal(layer.getStats().rawRowCount, 3);
+  assert.equal(layer.getStats().acceptedRowCount, 1);
+  assert.equal(layerFeedState(layer.getStats()), 'partial');
+  assert.equal(layer.hasContact('123456789'), true);
+
+  for (const extra of [
+    { stale: true },
+    { freshness: 'stale' },
+    { freshness: 'unknown', observedAtMs: null },
+    { transportStatus: 'stale' },
+  ]) {
+    const original = current;
+    current = { ...original, ...extra };
+    await layer.update();
+    assert.equal(layer.getStats().partial, true);
+    assert.equal(layerFeedState(layer.getStats()), 'stale');
+    current = original;
+  }
+  current = { ...current, transportStatus: 'reconnecting' };
+  await layer.update();
+  assert.equal(layerFeedState(layer.getStats()), 'degraded');
+  assert.match(layer.getStats().error, /reconnecting/);
+
+  current = vesselSnapshot({ rows: [valid], status: 'live' });
+  await layer.update();
+  assert.equal(layer.getStats().partial, false);
+  assert.equal(layer.getStats().stale, false);
+  assert.equal(layer.getStats().error, null);
+  assert.equal(layerFeedState(layer.getStats()), 'nominal');
+  current = { ...current, complete: false };
+  await layer.update();
+  assert.equal(layer.getStats().partial, true);
+  layer.destroy();
+  assert.equal(layer.getStats().partial, false);
+});

src/layers/vessels/queries.js

@@ -508,6 +508,7 @@ export function createQueries({
           : state.feed.loadingLabel,
         error: state.feed.error,
         stale: state.feed.stale,
+        partial: state.feed.partial,
         status:
           state.feed.firstConnectPhase === 'unavailable'
             ? 'unavailable'

src/layers/vessels/testing.js

@@ -37,6 +37,7 @@ export function createTesting({
     state.feed.loaded = options.loaded === true;
     state.feed.loading = options.loading === true;
     state.feed.stale = options.stale === true;
+    state.feed.partial = options.partial === true;
     state.feed.error = options.error || null;
     state.feed.lastUpdate = options.lastUpdate ?? null;
     state.records.all = records;