fix(street-level): keep explicit provider choices on filter-only updates

Review fixes on top of #1601:
- Only redirect a provider the params switch on to a keyless source, so a
  filter-only setParams (360°, SINCE) no longer moves an explicitly chosen
  keyless Mapillary to KartaView.
- Keyless QA gate: assert the new KartaView default and that the Mapillary
  chip explains its key instead of switching (it used to expect KEY REQUIRED).
- Tests: Graph-proxy keyReady, filter-only updates; shared test helper.
- README and CURRENT-STATE describe the keyless default.

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

src/layers/streetLevel/index.js

@@ -126,7 +126,7 @@ export function createStreetLevelLayer({
     });
   }
 
-  /** `def`, or the first keyless provider not refused when `def` has no key. */
+  /** `def` if its key is ready, else the first keyless provider not refused. */
   function keylessInstead(def, refused = () => false) {
     if (def.keyReady?.() !== false) return def;
     return defs.find((d) => !d.requiresKeyId && !refused(d.id)) || def;
@@ -594,15 +594,17 @@ export function createStreetLevelLayer({
         providerIds: state.providers.keys(),
         filter: state.filter,
       });
-      // Links and stored state omit Mapillary when it is on (the codec
-      // default), so a keyless install would restore a source it cannot draw.
+      // A restored "Mapillary on" (the codec default) would light a source a
+      // keyless install cannot draw. Only redirect a provider the params switch
+      // on: a filter-only update keeps whatever the user chose.
       const asked = litByParams(decoded.providers);
       const lit =
-        asked &&
-        keylessInstead(
-          state.providers.get(asked).def,
-          (id) => decoded.providers.get(id) === false,
-        ).id;
+        asked && decoded.providers.get(asked) === true
+          ? keylessInstead(
+              state.providers.get(asked).def,
+              (id) => decoded.providers.get(id) === false,
+            ).id
+          : asked;
       const before = litIds();
       for (const [id, entry] of state.providers)
         if (id !== lit) switchProvider(entry, false);

src/layers/streetLevel/index.test.mjs

@@ -1128,63 +1128,58 @@ test('the panel says why a lit Street View draws nothing off Google 3D', async (
   assert.match(view.meta, /Google Street View needs the Google 3D map/);
 });
 
-test('without a Mapillary key the first keyless source is lit instead', async (t) => {
-  const kartaViewSource = {
-    getTile: async () => ({ lines: [] }),
-    nearestPhotos: async () => [],
-    getPhoto: async () => {
-      throw new Error('KartaView has no such photo');
-    },
-    getSequencePhotos: async () => ({ photos: [], hasMore: false }),
-    probeImage: async () => true,
-  };
-  const lit = (hasToken) => {
-    const layer = createStreetLevelLayer({
-      providers: [
-        createMapillaryProvider({
-          source: fakeMapillarySource({ hasToken: () => hasToken }),
-          photoViewer: fakePhotoViewer(),
-        }),
-        createKartaViewProvider({ source: kartaViewSource }),
-      ],
-    });
-    t.after(() => layer.destroy());
-    return layer
-      .getUIState()
-      .providers.filter((provider) => provider.on)
-      .map((provider) => provider.id);
-  };
-  assert.deepEqual(lit(false), ['kartaview']);
-  assert.deepEqual(lit(true), ['mapillary']);
-});
-
-test('restoring the default "Mapillary on" without its key keeps a keyless source', (t) => {
+/** Mapillary (keyless unless `mapillary` says otherwise) plus KartaView. */
+function keylessLayer(t, mapillary = { hasToken: () => false }) {
   const layer = createStreetLevelLayer({
     providers: [
       createMapillaryProvider({
-        source: fakeMapillarySource({ hasToken: () => false }),
+        source: fakeMapillarySource(mapillary),
         photoViewer: fakePhotoViewer(),
       }),
-      createKartaViewProvider({
-        source: {
-          getTile: async () => ({ lines: [] }),
-          nearestPhotos: async () => [],
-          getPhoto: async () => null,
-          getSequencePhotos: async () => ({ photos: [], hasMore: false }),
-          probeImage: async () => true,
-        },
-      }),
+      createKartaViewProvider(),
     ],
   });
   t.after(() => layer.destroy());
-  const litIds = () =>
-    layer
-      .getUIState()
-      .providers.filter((provider) => provider.on)
-      .map((provider) => provider.id);
+  return layer;
+}
+const litProviders = (layer) =>
+  layer
+    .getUIState()
+    .providers.filter((provider) => provider.on)
+    .map((provider) => provider.id);
+
+test('without a Mapillary key the first keyless source is lit instead', (t) => {
+  assert.deepEqual(litProviders(keylessLayer(t)), ['kartaview']);
+  assert.deepEqual(litProviders(keylessLayer(t, {})), ['mapillary']);
+  // A token-adding Graph proxy counts as a key.
+  const proxied = keylessLayer(t, {
+    hasToken: () => false,
+    graphEndpoint: '/api/mapillary/graph',
+  });
+  assert.deepEqual(litProviders(proxied), ['mapillary']);
+});
+
+test('restoring the default "Mapillary on" without its key keeps a keyless source', (t) => {
+  const layer = keylessLayer(t);
   layer.setParams({ mapillary: true, providerSwitches: '' });
-  assert.deepEqual(litIds(), ['kartaview']);
+  assert.deepEqual(litProviders(layer), ['kartaview']);
   // A link that switches KartaView off keeps its word.
   layer.setParams({ mapillary: true, providerSwitches: 'kartaview-0' });
-  assert.deepEqual(litIds(), ['mapillary']);
+  assert.deepEqual(litProviders(layer), ['mapillary']);
+});
+
+test('filter-only updates keep the lit source, even a chosen keyless Mapillary', (t) => {
+  const layer = keylessLayer(t);
+  layer.setParams({ pano: 'pano' });
+  assert.deepEqual(litProviders(layer), ['kartaview']);
+  // What the MAPILLARY chip sends, and what stored state restores.
+  layer.setParams({ mapillary: true, providerSwitches: 'kartaview-0' });
+  for (const params of [{ pano: 'pano' }, { sinceDays: 365 }, {}]) {
+    layer.setParams(params);
+    assert.deepEqual(
+      litProviders(layer),
+      ['mapillary'],
+      JSON.stringify(params),
+    );
+  }
 });

src/layers/streetLevel/providers/mapillary/index.js

@@ -74,7 +74,7 @@ export function createMapillaryProvider({ source, photoViewer = null }) {
     name: MAPILLARY_NAME,
     label: MAPILLARY_LABEL,
     requiresKeyId: MAPILLARY_KEY_ID,
-    /** A browser token or a token-adding Graph proxy; else KEY REQUIRED. */
+    /** A browser token, or a Graph proxy that adds one server-side. */
     keyReady: () =>
       source.hasToken?.() !== false || Boolean(source.graphEndpoint),
     pickPrefix: PICK_PREFIX.root,