What causes "Output directory must be empty: ${outputDirectory}" in Hmbown/CodeWhale?

Hmbown/CodeWhale · error · Error

Output directory must be empty: ${outputDirectory}

Error message

Output directory must be empty: ${outputDirectory}

What it means

assemble() refuses to write into an OUTPUT_DIR that already contains any entries. Because it generates the checksum manifest over the final file set, a non-empty target could mix stale or foreign bytes into a shipped release, so it fails fast before copying anything.

Source

Thrown at scripts/release/assemble-release-assets.js:143

    let sourceStat;
    try {
      sourceStat = await fs.lstat(source);
    } catch (error) {
      if (error && error.code === "ENOENT") {
        throw new Error(`Downloaded release artifacts are missing ${name} at ${source}`);
      }
      throw error;
    }
    if (!sourceStat.isFile()) {
      throw new Error(`Downloaded release artifact must be a regular file: ${source}`);
    }
    sources.set(name, source);
  }

  await fs.mkdir(outputDirectory, { recursive: true });
  const existing = await fs.readdir(outputDirectory);
  if (existing.length > 0) {
    throw new Error(`Output directory must be empty: ${outputDirectory}`);
  }

  for (const name of copiedNames) {
    await fs.copyFile(sources.get(name), path.join(outputDirectory, name));
  }
  await fs.writeFile(
    path.join(outputDirectory, WINDOWS_LAUNCHER),
    windowsLauncherContents(),
    "utf8",
  );

  const checksumRows = [];
  for (const name of [...checksummedReleaseAssetNames()].sort()) {
    checksumRows.push(`${await sha256(path.join(outputDirectory, name))}  ${name}`);
  }
  await fs.writeFile(
    path.join(outputDirectory, CHECKSUM_MANIFEST),
    `${checksumRows.join("\n")}\n`,

View on GitHub (pinned to 8880682c63)

Solutions

Use a fresh empty directory: rm -rf release-out && node scripts/release/assemble-release-assets.js INPUT_DIR release-out
In CI, use a unique run-scoped path such as $RUNNER_TEMP/release-assets
Double-check argument order: INPUT_DIR (downloaded artifacts) first, OUTPUT_DIR second

Example fix

# before: second run reuses a non-empty output dir -> error
node scripts/release/assemble-release-assets.js artifacts-in release-out

# after
rm -rf release-out
node scripts/release/assemble-release-assets.js artifacts-in release-out

Defensive patterns

Strategy: validation

Validate before calling

#!/usr/bin/env bash
# CI pre-step: guarantee a clean output dir before assemble
OUT="$RUNNER_TEMP/release-assets"
rm -rf "$OUT" && mkdir -p "$OUT"
node scripts/release/assemble-release-assets.js "$ARTIFACTS_IN" "$OUT"

Prevention

Create the output directory fresh in the same command that runs assemble (rm -rf && mkdir -p)
Use runner-temp paths unique per job instead of workspace-relative output dirs
Never reuse a release output directory across attempts; each assemble run starts from empty

When it happens

Trigger: Re-running assemble into the same OUTPUT_DIR used by a previous attempt; passing a directory that already holds files (workspace dir, a folder with a README); pointing OUTPUT_DIR at INPUT_DIR by mistake.

Common situations: Retrying a failed release without cleaning the output directory; a CI step that pre-populates the output path; copy-paste invoking with in and out swapped.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@8880682c63 (2026-08-16). Data as JSON: /api/errors/604e4106c3f93dd8. Report an issue: GitHub.