archiveError function

String? archiveError(ArchiveFormat format, { required bool isDir, })

Validates format against whether the source isDir, returning an error message to show the user, or null when the combination is allowed.

A file may be compressed as .gz or .zip; a directory as .tar.gz or .zip. gzip cannot bundle a directory, and .tar.gz is not offered for a single file.

Implementation

String? archiveError(ArchiveFormat format, {required bool isDir}) {
  if (isDir && format == ArchiveFormat.gz) {
    return 'gzip cannot archive a directory; use --tar.gz or --zip';
  }
  if (!isDir && format == ArchiveFormat.tarGz) {
    return 'use --gz or --zip for a single file';
  }
  return null;
}