apache/hadoop · error · IOException

invalid argument to getLinkCount: file name is null

Error message

invalid argument to getLinkCount: file name is null

What it means

Error "invalid argument to getLinkCount: file name is null" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/HardLink.java:240

    try {
      FileStore store = Files.getFileStore(f.toPath());
      return store.supportsFileAttributeView(FILE_ATTRIBUTE_VIEW);
    } catch (IOException e) {
      LOG.warn("Failed to determine if hardlink is supported", e);
      return false;
    }
  }

   /**
   * Retrieves the number of links to the specified file.
    *
    * @param fileName file name.
    * @throws IOException raised on errors performing I/O.
    * @return link count.
   */
  public static int getLinkCount(File fileName) throws IOException {
    if (fileName == null) {
      throw new IOException(
          "invalid argument to getLinkCount: file name is null");
    }
    if (!fileName.exists()) {
      throw new FileNotFoundException(fileName + " not found.");
    }

    if (supportsHardLink(fileName)) {
      return (int) Files.getAttribute(fileName.toPath(), FILE_ATTRIBUTE);
    }

    // construct and execute shell command
    String[] cmd = getHardLinkCommand.linkCount(fileName);
    String inpMsg = null;
    String errMsg = null;
    int exitValue = -1;
    BufferedReader in = null;

    ShellCommandExecutor shexec = new ShellCommandExecutor(cmd);

View on GitHub (pinned to 2add963021)

Solutions

1. Pass a non-null File to getLinkCount.
2. Validate the file path before querying link count.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/HardLink.java:240 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/4bf94f38c1b9c123. Report an issue: GitHub.