Preserve positionless aircraft identities for classification

src/layers/aircraft/classification.js

@@ -129,10 +129,17 @@ export function createMilitaryRegistry({ source, now = Date.now } = {}) {
     const signal = AbortSignal.any([owner.signal, AbortSignal.timeout(10000)]);
     _polling = true;
     try {
-      const snapshot = await requestSource.getSnapshot({}, { signal });
+      const ids =
+        typeof requestSource.getIdentities === 'function'
+          ? await requestSource.getIdentities({}, { signal })
+          : (await requestSource.getSnapshot({}, { signal })).records.map(
+              (record) => record.id,
+            );
       signal.throwIfAborted();
       if (lifetime !== owner) return;
-      registerMilitaryIcaos(snapshot.records.map((record) => record.id));
+      if (!Array.isArray(ids))
+        throw new TypeError('Expected aircraft identities');
+      registerMilitaryIcaos(ids);
     } catch {
       // Keep the existing classification through source outages.
     } finally {

src/layers/aircraft/classification.test.mjs

@@ -121,3 +121,21 @@ test('disposing a registry fed directly by its layer also clears classification'
   registry.dispose();
   assert.equal(registry.isMilitaryIcao('abc123'), false);
 });
+
+test('classification prefers an explicit identity capability over positioned observations', async () => {
+  const registry = createMilitaryRegistry({
+    source: {
+      getSnapshot() {
+        assert.fail(
+          'position snapshots must not replace an available identity capability',
+        );
+      },
+      async getIdentities() {
+        return ['abc123'];
+      },
+    },
+  });
+  await registry.refreshMilitaryRegistryIfStale();
+  assert.equal(registry.isMilitaryIcao('abc123'), true);
+  registry.dispose();
+});

src/sources/live/aircraft.js

@@ -165,3 +165,16 @@ export function normalizeAircraftTrack(
     ];
   });
 }
+
+/** Known source identities are useful for classification even without positions. */
+export function readsbIdentities(payload) {
+  const admitted = admitRecords(
+    payload?.ac,
+    (row) => {
+      const id = cleanText(row?.hex).toLowerCase();
+      return id ? { id } : null;
+    },
+    'aircraft identities',
+  );
+  return admitted.records.map((record) => record.id);
+}

src/sources/live/contract.test.mjs

@@ -271,3 +271,45 @@ test('out-of-range source epochs do not reach Date or globe time constructors',
   assert.equal(snapshot.records[0].positionTimeMs, null);
   assert.equal(snapshot.records[0].contactTimeMs, null);
 });
+
+test('classification identities include positionless aircraft without admitting them to rendering', async () => {
+  const source = createAdsbLolSource({
+    fetchImpl: async () =>
+      response({
+        ac: [
+          { hex: ' ABC123 ' },
+          { hex: 'abc123' },
+          { hex: 'def456', lat: 30, lon: -97 },
+        ],
+      }),
+  });
+  assert.deepEqual(await source.getIdentities(), ['abc123', 'def456']);
+  const snapshot = await source.getSnapshot();
+  assert.deepEqual(
+    snapshot.records.map((record) => record.id),
+    ['def456'],
+  );
+  assert.equal(snapshot.complete, false);
+});
+
+test('identity lookup validates its response and honors body-parse cancellation', async () => {
+  const malformed = createAdsbLolSource({
+    fetchImpl: async () => response({ ac: [{}] }),
+  });
+  await assert.rejects(malformed.getIdentities(), /Malformed/);
+  const abort = new AbortController();
+  const source = createAdsbLolSource({
+    fetchImpl: async () => ({
+      ok: true,
+      status: 200,
+      headers: new Headers(),
+      async json() {
+        abort.abort();
+        return { ac: [{ hex: 'abc123' }] };
+      },
+    }),
+  });
+  await assert.rejects(source.getIdentities({}, { signal: abort.signal }), {
+    name: 'AbortError',
+  });
+});

src/sources/live/index.js

@@ -5,6 +5,7 @@ export {
   normalizeAircraftTrack,
   openSkySnapshot,
   readsbSnapshot,
+  readsbIdentities,
 } from './aircraft.js';
 export {
   normalizeVesselObservation,

src/sources/live/standalone.js

@@ -9,6 +9,7 @@ import {
   normalizeAircraftTrack,
   openSkySnapshot,
   readsbSnapshot,
+  readsbIdentities,
 } from './aircraft.js';
 import { normalizeVesselTrack, vesselSnapshot } from './vessels.js';
 
@@ -113,6 +114,16 @@ export function createAdsbLolSource({
 } = {}) {
   return {
     label: 'adsb.lol',
+    async getIdentities(_query = {}, { signal } = {}) {
+      const { response, payload } = await readResponse(
+        fetchImpl,
+        '/api/adsblol/mil',
+        { signal },
+        'adsb.lol',
+      );
+      if (!response.ok) throw httpError(response, 'adsb.lol');
+      return readsbIdentities(payload);
+    },
     async getSnapshot(_query = {}, { signal } = {}) {
       const { response, payload } = await readResponse(
         fetchImpl,