anomalyco/sst · error

failed to open zip: %w

Error message

failed to open zip: %w

What it means

`extractZip` opens the .whl with Go's `zip.OpenReader`; any failure to open or parse the zip central directory is wrapped in this error. It is the low-level sibling of the corrupt-wheel problem: the file exists but is not a readable zip.

Source

Thrown at pkg/runtime/python/build.go:353

	extractedDir := filepath.Join(outputDir, dirName)
	targetDir := filepath.Join(outputDir, baseName)

	// Move extracted directory to target
	if err := moveExtractedPackage(extractedDir, targetDir, baseName); err != nil {
		return fmt.Errorf("failed to move extracted package: %w", err)
	}

	// Remove the original archive
	os.Remove(archiveFile)

	return nil
}

// extractZip extracts a zip archive (used for .whl files) to the destination directory.
func extractZip(archiveFile, destDir string) error {
	r, err := zip.OpenReader(archiveFile)
	if err != nil {
		return fmt.Errorf("failed to open zip: %w", err)
	}
	defer r.Close()

	for _, f := range r.File {
		// Guard against zip slip
		target := filepath.Join(destDir, f.Name)
		if !strings.HasPrefix(filepath.Clean(target), filepath.Clean(destDir)+string(os.PathSeparator)) {
			return fmt.Errorf("illegal file path in zip: %s", f.Name)
		}

		if f.FileInfo().IsDir() {
			if err := os.MkdirAll(target, 0755); err != nil {
				return err
			}
			continue
		}

		if err := os.MkdirAll(filepath.Dir(target), 0755); err != nil {

View on GitHub (pinned to a0bd20f762)

Solutions

1. Delete the invalid .whl and rebuild so pip re-downloads it
2. Verify zip integrity: `python -m zipfile -t <file>.whl` or `unzip -t`
3. Clear CI/build caches that may hold partially written wheels
4. Ensure sufficient disk space and stable network (disable restrictive proxies) during install

Example fix

// before: cached truncated wheel in CI
# sst deploy -> failed to open zip: unexpected EOF
// after: clear cache then deploy
cache.clear() ; sst deploy

import { readFileSync } from "fs";
const fd = readFileSync(archivePath);
if (!(fd[0] === 0x50 && fd[1] === 0x4b)) throw new Error(`${archivePath} is not a zip (wheel)`);

try {
  await buildPackage(...);
} catch (e) {
  if (String(e).includes("failed to open zip")) {
    console.error("Wheel is not a valid zip — force re-download:", e);
  }
  throw e;
}

When it happens

Trigger: `processPackageArchive` matched a `.whl` whose bytes are not a zip — 0-byte file, truncated download, or a file with a .whl extension that is actually text/binary of another format.

Common situations: Interrupted or proxied pip downloads; disk-full writes; CI caches restoring partially written artifacts.

Related errors

• failed to extract wheel: %w
• failed to process archive %s: %w
• failed to extract archive: %w
• illegal file path in zip: %s
• failed to create gzip reader: %w

AI-assisted analysis of anomalyco/sst@a0bd20f762 (2026-08-30). Data as JSON: /api/errors/fb08c7c680bc1555. Report an issue: GitHub.