fix(maps): stop delivering settled state to detached subscribers

src/maps/map-subscription-ownership.test.mjs

@@ -0,0 +1,55 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { MapSourceController } from './controller.js';
+function fixture() {
+  return new MapSourceController(
+    {
+      scene: {
+        globe: { show: true },
+        requestRender() {},
+        frameState: {
+          creditDisplay: { addStaticCredit() {}, removeStaticCredit() {} },
+        },
+        primitives: { add() {}, remove() {} },
+      },
+      imageryLayers: { add() {}, remove() {} },
+    },
+    {
+      registry: {
+        defaultId: 'fixture',
+        sources: [
+          {
+            descriptor: { id: 'fixture', label: 'Fixture', kind: 'imagery' },
+            imagery: async () => ({}),
+          },
+        ],
+      },
+      createImageryLayer: (provider) => ({ provider }),
+    },
+  );
+}
+test('an unsubscribed owner is skipped in the same map settlement delivery', async () => {
+  const controller = fixture();
+  const calls = [];
+  let detach;
+  controller.subscribe(() => {
+    calls.push('first');
+    detach();
+  });
+  detach = controller.subscribe(() => calls.push('detached'));
+  controller.subscribe(() => calls.push('last'));
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['first', 'last']);
+  controller.destroy();
+});
+test('destroying the controller during delivery stops remaining listeners', async () => {
+  const controller = fixture();
+  const calls = [];
+  controller.subscribe(() => {
+    calls.push('destroy');
+    controller.destroy();
+  });
+  controller.subscribe(() => calls.push('detached'));
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['destroy']);
+});