From ae4dbc5c4845ff5a9aaeace44574004a03feb63f Mon Sep 17 00:00:00 2001
From: Mrxuba <56430542+Mrxuba@users.noreply.github.com>
Date: Fri, 16 Oct 2026 17:11:27 +0800
Subject: [PATCH] fix(media): guard SynchronizedMedia.frameDomain before
 reading frameRate

verifySynchronizedMedia dereferenced item.frameDomain.frameRate (and
.frameCount) right after confirming only that the top-level value is an
object. When frameDomain is missing or not an object it threw a bare
"Cannot read properties of undefined (reading 'frameRate')" TypeError
instead of a stated validation error. That is what surfaces when an
older or hand-edited result.json is read (see #388).

Add the same object() guard the sibling verifiers already use so a
malformed frame domain is reported as
"SynchronizedMedia.frameDomain must be an object".

Adds packages/media/test/identity.test.ts covering a well-formed value
and missing / non-object frame domains.
---
 packages/media/src/identity.ts       |  1 +
 packages/media/test/identity.test.ts | 36 ++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 packages/media/test/identity.test.ts

diff --git a/packages/media/src/identity.ts b/packages/media/src/identity.ts
index c7eb4accf..860b1ce97 100644
--- a/packages/media/src/identity.ts
+++ b/packages/media/src/identity.ts
@@ -169,6 +169,7 @@ export function synchronizedMediaSampleFrames(value: SynchronizedMedia): number
 
 export function verifySynchronizedMedia(value: unknown): asserts value is SynchronizedMedia {
   const item = object(value, "SynchronizedMedia") as unknown as SynchronizedMedia;
+  object(item.frameDomain, "SynchronizedMedia.frameDomain");
   verifyRational(item.frameDomain.frameRate, "SynchronizedMedia.frameDomain.frameRate");
   positiveInteger(item.frameDomain.frameCount, "SynchronizedMedia.frameDomain.frameCount");
   synchronizedMediaSampleFrames(item);
diff --git a/packages/media/test/identity.test.ts b/packages/media/test/identity.test.ts
new file mode 100644
index 000000000..814136a2f
--- /dev/null
+++ b/packages/media/test/identity.test.ts
@@ -0,0 +1,36 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { verifySynchronizedMedia } from "../src/index.js";
+import type { SynchronizedMedia } from "../src/index.js";
+import { fixtureResource } from "../../../test/fixture-resource.js";
+
+const media: SynchronizedMedia = {
+  frameDomain: { frameRate: { numerator: 30, denominator: 1 }, frameCount: 60 },
+  visual: {
+    artifact: { kind: "blob", resource: fixtureResource("identity:visual"), size: 1, mediaType: "video/mp4" },
+    width: 1920, height: 1080,
+  },
+  audio: { artifact: { kind: "blob", resource: fixtureResource("identity:audio"), size: 1, mediaType: "audio/wav" } },
+};
+
+test("verifySynchronizedMedia accepts a well-formed value", () => {
+  assert.doesNotThrow(() => verifySynchronizedMedia(media));
+});
+
+test("verifySynchronizedMedia rejects a missing frame domain with a stated error", () => {
+  const { frameDomain: _omitted, ...withoutFrameDomain } = media;
+  assert.throws(
+    () => verifySynchronizedMedia(withoutFrameDomain),
+    /SynchronizedMedia\.frameDomain must be an object/,
+  );
+});
+
+test("verifySynchronizedMedia rejects a non-object frame domain with a stated error", () => {
+  for (const frameDomain of [null, "30/1", 30] as const) {
+    assert.throws(
+      () => verifySynchronizedMedia({ ...media, frameDomain }),
+      /SynchronizedMedia\.frameDomain must be an object/,
+    );
+  }
+});