fix(skills): read BGM logs without pathname prechecks (#3769)

skills-manifest.json

@@ -34,7 +34,7 @@
       "files": 11
     },
     "hyperframes-core": {
-      "hash": "033a6c675e66a5e7",
+      "hash": "6921c3b1dbeefb30",
       "files": 20
     },
     "hyperframes-creative": {
@@ -50,8 +50,8 @@
       "files": 12
     },
     "media-use": {
-      "hash": "5b35f62a2c59f220",
-      "files": 153
+      "hash": "e870f18213f27c8b",
+      "files": 154
     },
     "motion-graphics": {
       "hash": "853ac75cbab69036",
@@ -62,12 +62,12 @@
       "files": 132
     },
     "pr-to-video": {
-      "hash": "9ce0b5a7c75e969f",
+      "hash": "e3c6d1527c04a804",
       "files": 30
     },
     "product-launch-video": {
-      "hash": "01256d74e511f163",
-      "files": 29
+      "hash": "71226b200d8adae3",
+      "files": 30
     },
     "remotion-to-hyperframes": {
       "hash": "79fcf8e9641d126e",

skills/media-use/audio/scripts/wait-bgm.mjs

@@ -48,10 +48,14 @@ function isProcessAlive(pid) {
 }
 
 function readTail(path, maxChars = 6000) {
-  if (!path || !existsSync(path)) return "";
-  const s = statSync(path);
-  const txt = readFileSync(path, "utf8");
-  return txt.slice(Math.max(0, txt.length - Math.min(maxChars, s.size)));
+  if (!path) return "";
+  try {
+    const txt = readFileSync(path, "utf8");
+    return txt.slice(Math.max(0, txt.length - maxChars));
+  } catch (error) {
+    if (error.code === "ENOENT" || error.code === "ENOTDIR") return "";
+    throw error;
+  }
 }
 
 function detectFailure(logTail) {

skills/media-use/audio/scripts/wait-bgm.test.mjs

@@ -0,0 +1,65 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { test } from "node:test";
+import { runInNewContext } from "node:vm";
+
+const source = readFileSync(new URL("./wait-bgm.mjs", import.meta.url), "utf8");
+const start = source.indexOf("function readTail(");
+const end = source.indexOf("\nfunction detectFailure(", start);
+function load(read) {
+  return runInNewContext(`${source.slice(start, end)}; readTail`, {
+    readFileSync: read,
+    existsSync: () => true,
+    statSync: () => {
+      throw new Error("pathname stat must not precede log read");
+    },
+  });
+}
+
+test("reads a log once without a separate pathname check", () => {
+  let calls = 0;
+  const read = load((path, encoding) => {
+    calls++;
+    assert.equal(path, "renderer.log");
+    assert.equal(encoding, "utf8");
+    return "prefix\nRuntimeError: failed";
+  });
+  assert.equal(read("renderer.log", 20), "RuntimeError: failed");
+  assert.equal(calls, 1);
+});
+
+test("preserves UTF-16 character tail boundaries and zero-length tails", () => {
+  const txt = "🎵日本語".repeat(2000);
+  const read = load(() => txt);
+  assert.equal(read("log"), txt.slice(-6000));
+  assert.equal(read("log", 0), "");
+});
+
+for (const code of ["ENOENT", "ENOTDIR"]) {
+  test(`a log removed during polling is absent (${code})`, () => {
+    const read = load(() => {
+      throw Object.assign(new Error(code), { code });
+    });
+    assert.equal(read("log"), "");
+  });
+}
+
+test("preserves unexpected read errors", () => {
+  const error = Object.assign(new Error("denied"), { code: "EACCES" });
+  assert.throws(
+    () =>
+      load(() => {
+        throw error;
+      })("log"),
+    (caught) => caught === error,
+  );
+});
+
+test("empty log path does not access the filesystem", () => {
+  assert.equal(
+    load(() => {
+      throw new Error("unexpected read");
+    })(""),
+    "",
+  );
+});