GoogleContainerTools/jib · error · CacheCorruptedException

Expected valid layer digest as contents of selector file `<s

Error message

Expected valid layer digest as contents of selector file `<selectorFile>` for selector `<selector>`, but got: <contents>

What it means

Selector files map one layer digest to an alternative (usually uncompressed) layer digest. select(selector) reads the selector file and expects its UTF-8 contents to be a valid DescriptorDigest hash; if DescriptorDigest.fromHash() fails, CacheCorruptedException is thrown showing the file path, the selector hash, and the actual (invalid) contents.

Source

Thrown at jib-core/src/main/java/com/google/cloud/tools/jib/cache/CacheStorageReader.java:258

   * @param selector the selector
   * @return the layer digest {@code selector} selects, if found
   * @throws CacheCorruptedException if the selector file contents was not a valid layer digest
   * @throws IOException if an I/O exception occurs
   */
  Optional<DescriptorDigest> select(DescriptorDigest selector)
      throws CacheCorruptedException, IOException {
    Path selectorFile = cacheStorageFiles.getSelectorFile(selector);
    if (!Files.exists(selectorFile)) {
      return Optional.empty();
    }

    String selectorFileContents =
        new String(Files.readAllBytes(selectorFile), StandardCharsets.UTF_8);
    try {
      return Optional.of(DescriptorDigest.fromHash(selectorFileContents));

    } catch (DigestException ex) {
      throw new CacheCorruptedException(
          cacheStorageFiles.getCacheDirectory(),
          "Expected valid layer digest as contents of selector file `"
              + selectorFile
              + "` for selector `"
              + selector.getHash()
              + "`, but got: "
              + selectorFileContents);
    }
  }
}

View on GitHub (pinned to fb949e2676)

Solutions

1. Delete the offending selector file (path is given in the message) and rebuild
2. Clear the entire cache directory to force selectors to be regenerated
3. Inspect the file contents shown in the error to identify what corrupted it (often empty)
4. Ensure builds are not killed abruptly (avoid SIGKILL/cancelled jobs mid-write)

Example fix

// before: selector file contains "" or "sha256:abc"
// after: remove it; Jib rewrites it
rm "$(echo $HOME)/.cache/google-cloud-tools-java/jib/selectors/<selector>"

String s = Files.readString(selectorFile).trim();
if (!s.matches("[0-9a-f]{64}")) Files.deleteIfExists(selectorFile);

boolean isValidDigest(String s) {
  return s != null && s.matches("[0-9a-f]{64}");
}

try {
  build();
} catch (CacheCorruptedException e) {
  if (e.getMessage().contains("selector file")) {
    Files.deleteIfExists(selectorPathFrom(e.getMessage()));
    build();
  }
}

When it happens

Trigger: CacheStorageReader.select() reads a selector file whose contents are not a 64-character hex digest — e.g. empty file, truncated write, or a path/blob reference instead of a hash.

Common situations: JVM or machine crash mid-write of the selector file, disk corruption, manual editing, or cache manipulation by external scripts.

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

• Layer file did not include valid hash: <layerFile>
• Manifest cache empty
• Manifest(s) missing
• Manifest list missing
• Schema 1 manifests corrupted

AI-assisted analysis of GoogleContainerTools/jib@fb949e2676 (2026-09-06). Data as JSON: /api/errors/3694ebb6428a930a. Report an issue: GitHub.