From 299a5943a01b754b5a268d6fc4d14551fbfbdd12 Mon Sep 17 00:00:00 2001
From: German Khokhlov <ouchlock@gmail.com>
Date: Tue, 3 Nov 2026 19:46:31 +0400
Subject: [PATCH] Ignore a late image or error from a street-level provider the
 user switched away from

---
 src/layers/streetLevel/edgeCases.test.mjs | 91 +++++++++++++++++++++++
 src/layers/streetLevel/index.js           | 11 ++-
 2 files changed, 100 insertions(+), 2 deletions(-)
 create mode 100644 src/layers/streetLevel/edgeCases.test.mjs

diff --git a/src/layers/streetLevel/edgeCases.test.mjs b/src/layers/streetLevel/edgeCases.test.mjs
new file mode 100644
index 000000000..bca078618
--- /dev/null
+++ b/src/layers/streetLevel/edgeCases.test.mjs
@@ -0,0 +1,91 @@
+// Edge cases from docs/migration/planet-separation/layers.md (street-level):
+// without a paid source, a late answer from a provider the user switched away
+// from is ignored and the lit provider keeps the panel.
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import * as Cesium from 'cesium';
+import { createStreetLevelLayer } from './index.js';
+import {
+  fakeCesiumViewer,
+  fakeStreetLevelProvider as fakeProvider,
+} from '../../testSupport/streetLevelFakes.mjs';
+
+const settle = () => new Promise((resolve) => setTimeout(resolve, 0));
+
+function deferred() {
+  let resolve;
+  const promise = new Promise((done) => (resolve = done));
+  return { promise, resolve };
+}
+
+/** Two keyless providers; the first answers its nearest lookup on demand. */
+async function twoProviders(t) {
+  const saved = globalThis.document;
+  const drawing = new Proxy({}, { get: () => () => ({ addColorStop() {} }) });
+  globalThis.document = Object.assign(new EventTarget(), {
+    createElement: () => ({ getContext: () => drawing }),
+  });
+  t.mock.method(
+    Cesium.GroundPolylinePrimitive,
+    'initializeTerrainHeights',
+    async () => {},
+  );
+  const lookups = [];
+  const previous = fakeProvider({
+    nearestImage: (point, { signal } = {}) => {
+      const answer = deferred();
+      lookups.push({ point, signal, answer });
+      return answer.promise;
+    },
+  });
+  const lit = fakeProvider({
+    id: 'panoramax',
+    pickPrefix: 'pmx:',
+    nearestImage: async () => 'pmx-1',
+  });
+  const viewer = fakeCesiumViewer();
+  const layer = createStreetLevelLayer({ providers: [previous, lit] });
+  layer.init(viewer);
+  layer.enable(viewer);
+  layer.attachViewerHost({});
+  t.after(() => {
+    layer.destroy();
+    globalThis.document = saved;
+  });
+  await settle();
+  return { layer, previous, lit, lookups };
+}
+
+test('edge:street-level: a late nearest answer from the previous provider is ignored', async (t) => {
+  const { layer, previous, lit, lookups } = await twoProviders(t);
+  const stale = layer.openNearest({ lat: 38.58, lon: -121.49 });
+  await settle();
+  layer.setProviderEnabled('panoramax', true);
+  assert.equal(await layer.openNearest({ lat: 38.58, lon: -121.49 }), true);
+  lookups[0].answer.resolve('mly-late');
+  assert.equal(await stale, false);
+  await settle();
+  assert.deepEqual(previous.calls.open, []);
+  assert.deepEqual(lit.calls.open, ['pmx-1']);
+  const { street } = layer.getUIState();
+  assert.equal(street.providerId, 'panoramax');
+  assert.equal(street.error, null);
+  assert.equal(street.loading, false);
+});
+
+test('edge:street-level: a switched-off provider cannot open an image or post an error late', async (t) => {
+  const { layer, previous, lit } = await twoProviders(t);
+  const late = previous.context().actions;
+  layer.setProviderEnabled('panoramax', true);
+  assert.equal(await layer.openNearest({ lat: 1, lon: 2 }), true);
+  // The darkened provider's own work (a sequence step, a cone it had queued)
+  // finishes after the switch.
+  assert.equal(await late.openImage('mly-late'), false);
+  late.reportError('Sequence images unavailable');
+  await settle();
+  assert.deepEqual(previous.calls.open, []);
+  assert.deepEqual(lit.calls.open, ['pmx-1']);
+  const { street } = layer.getUIState();
+  assert.equal(street.providerId, 'panoramax');
+  assert.equal(street.error, null);
+});
diff --git a/src/layers/streetLevel/index.js b/src/layers/streetLevel/index.js
index 926db23db..bb69ff043 100644
--- a/src/layers/streetLevel/index.js
+++ b/src/layers/streetLevel/index.js
@@ -100,9 +100,14 @@ export function createStreetLevelLayer({
       waitingForView: () => waitingForView,
       notify,
       actions: {
-        /** `{frame: false}` opens it without moving the camera. */
+        /**
+         * `{frame: false}` opens it without moving the camera. A provider
+         * switched off (or a layer turned off) answers late: ignored.
+         */
         openImage: (imageId, options) =>
-          openImage(entry.def.id, imageId, options),
+          state.enabled && entry.on
+            ? openImage(entry.def.id, imageId, options)
+            : Promise.resolve(false),
         /** This provider's image nearest a point the user picked on the map. */
         openNearest: (point) =>
           layer.openNearest(point, {
@@ -115,6 +120,8 @@ export function createStreetLevelLayer({
          */
         reportError: (message) => {
           if (message) {
+            // Another source owns the panel now; its late failure is not news.
+            if (!state.enabled || !entry.on) return;
             state.street.error = entry.reportedError = message;
           } else {
             if (!entry.reportedError) return;