= What? =

CUPS printer drivers contain a field named `ppds_compressd_b64`, which is not generated deterministically.

[[https://reproducible.debian.net/issues/ppds_compressed_b64_issue.html|Known affected packages]].

= Detection =

A `/usr/lib/cups/driver/*` file containing:

{{{
    # PPDs Archive
    ppds_compressed_b64 = b"/Td6WFoAAATm1rRGAgAhARYAAAB0...a very long line.
}}}

= Cause / Solution =

ppds_compressed_b64 is a base64 encoding of a xz'd compressed Python pickle of a dict. This is generated by the `pyppd` binary during the build process (usually called by `dh_pyppd`). Non-determinism was added by the pickling process, as well as by the ordering of ppd/ppd.gz files as found by pyppd. Replacing python-specific pickling with dumping to json (modulo base64'ing and encoding/decoding to/from ASCII), and ordering the file list was implemented in pyppd 1.0.1-4. Make sure to retry with this version.