Merge pull request #1046 from rudycelekli/contrib/gods-025-asset-stream-cancellation-20261011-reviewed

fix(director): reject cancellation during the final asset stream read

CHANGELOG.md

@@ -36,6 +36,8 @@
 
 - Director timeline seeks cross the dateline along the short longitude arc.
 
+- Director assets cancelled during the final stream read are discarded with reader cleanup.
+
 - Analyst queries preserve useful rows when an upstream timestamp is outside the supported date range.
 
 - Fire detections with missing or impossible positions are skipped while genuine zero coordinates remain valid.

docs/CURRENT-STATE.md

@@ -398,6 +398,10 @@ and geographic placement remain distinct; Stop/replacement releases resources.
 Import acquires nothing. See [data packs](DIRECTOR-DATA-PACKS.md). Existing scene
 content, assets and credit remain unchanged.
 
+The asset directory source rejects with the caller's abort reason if
+cancellation arrives during any read, including the final one, or while the
+reader is being released.
+
 Director version-4 documents add named geographic anchors and optional explicit
 camera moves with easing, duration and holds. Playback and seek share one
 coordinate sampler; navigation/manual input revokes authored motion and pending

src/director/packs/asset-stream-cancellation.test.mjs

@@ -0,0 +1,79 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createAssetDirectorySource } from './source.js';
+test('cancellation during the terminating read cannot return a scene asset', async () => {
+  for (const cancel of [true, false]) {
+    const controller = new AbortController();
+    let reads = 0,
+      cancelled = 0,
+      released = 0;
+    const source = createAssetDirectorySource({
+      baseUrl: 'https://fixture.example/assets/',
+      fetchImpl: async () => ({
+        ok: true,
+        headers: new Headers({ 'content-type': 'application/octet-stream' }),
+        body: {
+          getReader() {
+            return {
+              async read() {
+                reads++;
+                if (reads === 1)
+                  return { done: false, value: new Uint8Array([1, 2]) };
+                if (cancel) controller.abort();
+                return { done: true };
+              },
+              async cancel() {
+                cancelled++;
+              },
+              releaseLock() {
+                released++;
+              },
+            };
+          },
+        },
+      }),
+    });
+    const pending = source({ path: 'scene.bin', signal: controller.signal });
+    if (cancel) await assert.rejects(pending, { name: 'AbortError' });
+    else assert.deepEqual([...(await pending).bytes], [1, 2]);
+    assert.equal(cancelled, 1);
+    assert.equal(released, 1);
+  }
+});
+
+test('cancellation during reader cleanup cannot return a scene asset', async () => {
+  const controller = new AbortController();
+  const reason = new DOMException('scene changed', 'AbortError');
+  let released = 0;
+  const source = createAssetDirectorySource({
+    baseUrl: 'https://fixture.example/assets/',
+    fetchImpl: async () => ({
+      ok: true,
+      headers: new Headers(),
+      body: {
+        getReader() {
+          let reads = 0;
+          return {
+            async read() {
+              reads++;
+              return reads === 1
+                ? { done: false, value: new Uint8Array([1]) }
+                : { done: true };
+            },
+            async cancel() {
+              controller.abort(reason);
+            },
+            releaseLock() {
+              released++;
+            },
+          };
+        },
+      },
+    }),
+  });
+  await assert.rejects(
+    source({ path: 'scene.bin', signal: controller.signal }),
+    (error) => error === reason,
+  );
+  assert.equal(released, 1);
+});

src/director/packs/source.js

@@ -41,6 +41,7 @@ export function createAssetDirectorySource({
       for (;;) {
         signal?.throwIfAborted();
         const { done, value } = await reader.read();
+        signal?.throwIfAborted();
         if (done) break;
         length += value.byteLength;
         if (length > maxBytes) throw new Error('Asset exceeds byte limit');
@@ -50,6 +51,8 @@ export function createAssetDirectorySource({
       await reader.cancel().catch(() => {});
       reader.releaseLock();
     }
+    // Cleanup awaits too; a cancel during it must still discard the asset.
+    signal?.throwIfAborted();
     const bytes = new Uint8Array(length);
     let offset = 0;
     for (const chunk of chunks) {