MyCATApache/Mycat-Server · error · IOException

Failed to list files for dir:

Error message

Failed to list files for dir: 

What it means

listFilesSafely is JavaUtils' internal helper used by deleteRecursively to enumerate a directory's children. It throws IOException when File.listFiles() returns null, which means the path is not a readable directory (e.g. permission denied or an I/O error) even though it exists.

Solutions

1. Verify the path is a directory with read+execute permission before recursing (file.isDirectory() && file.canRead()).
2. Fix permissions (chmod / chown) on the offending directory reported in the message.
3. Check whether the path is a symlink or special file and resolve/handle it before deletion.

Example fix

// before
JavaUtils.deleteRecursively(dir);
// after
if (dir.isDirectory() && dir.canRead()) {
  JavaUtils.deleteRecursively(dir);
} else {
  throw new IOException("Not a readable directory: " + dir);
}

if (!dir.isDirectory() || !dir.canRead()) {
  throw new IOException("Cannot list directory: " + dir);
}

try {
  JavaUtils.deleteRecursively(dir);
} catch (IOException e) {
  logger.warn("Delete failed (list problem?): {}", e.getMessage());
}

When it happens

Trigger: deleteRecursively invoked on a path that exists but is not a readable directory, or on a directory whose permissions prevent listing (no read/execute bit), or a filesystem error.

Common situations: Deleting trees spanning directories with mixed ownership/permissions; the target path replaced by a symlink or special file; NFS/permissions issues where exists() is true but listFiles() fails.

Related errors

• Failed to create local dir in $newDir.
• Failed to delete:
• Mkdirs failed to create
• error while calling spill() on
• error while calling spill() on

AI-assisted analysis of MyCATApache/Mycat-Server@65f8d8beb7 (2026-09-11). Data as JSON: /api/errors/0cdbdf7f921127ac. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/io/mycat/memory/unsafe/utils/JavaUtils.java:96

        }
      }
      if (savedIOException != null) {
        throw savedIOException;
      }
    }

    boolean deleted = file.delete();
    // Delete can also fail if the file simply did not exist.
    if (!deleted && file.exists()) {
      throw new IOException("Failed to delete: " + file.getAbsolutePath());
    }
  }

  private static File[] listFilesSafely(File file) throws IOException {
    if (file.exists()) {
      File[] files = file.listFiles();
      if (files == null) {
        throw new IOException("Failed to list files for dir: " + file);
      }
      return files;
    } else {
      return new File[0];
    }
  }

  private static boolean isSymlink(File file) throws IOException {
    Preconditions.checkNotNull(file);
    File fileInCanonicalDir = null;
    if (file.getParent() == null) {
      fileInCanonicalDir = file;
    } else {
      fileInCanonicalDir = new File(file.getParentFile().getCanonicalFile(), file.getName());
    }
    return !fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile());
  }

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