fix(share): reject inherited style keys during restore

src/view/index.js

@@ -370,7 +370,9 @@ export function viewFromParams(params) {
       pitch_deg: number('pitch'),
     },
     layers: state?.enabledLayerIds ?? [],
-    style: STYLES_BY_URL_NAME[params.get('style')] ?? null,
+    style: Object.hasOwn(STYLES_BY_URL_NAME, params.get('style'))
+      ? STYLES_BY_URL_NAME[params.get('style')]
+      : null,
     map: VIEW_MAPS.includes(map) ? map : null,
     follow,
     annotations: annotationsFromParams(params),

src/view/index.test.mjs

@@ -126,3 +126,20 @@ test('annotations travel in the link, keeping only what the app draws', async ()
   // Too long for a link: the view keeps them, the link leaves them out.
   assert.equal(viewToParams(many).has('an'), false);
 });
+
+test('inherited and unknown style keys do not corrupt a restored view', () => {
+  for (const style of [
+    'constructor',
+    '__proto__',
+    'toString',
+    'hasOwnProperty',
+    'unknown',
+  ]) {
+    const view = viewFromParams(
+      new URLSearchParams({ lat: '10', lon: '20', style, map: 'osm' }),
+    );
+    assert.equal(view.style, null);
+    assert.equal(view.map, 'osm');
+    assert.equal(view.camera.lat, 10);
+  }
+});