dak should handle invalid .changes files better. Currently exceptions
raised in process_upload.py's process_it (l. 463):

    with daklib.archive.ArchiveUpload(directory, changes, keyrings) as
upload:

are not handled. In particular, .changes with invalid Checksum-* fields,
that for example only list files in one of the various Checksum-* and
Files fields, do not generate a rejection mail, but only an internal error.

Ansgar