Bug#900593: diffoscope: GNU tar xattrs result in: libarchive: Ignoring malformed pax extended attribute

[Tianon Gravi]

On Fri, 1 Jun 2018 12:25:15 -0700 Tianon Gravi <tianon at debian.org> wrote:
> The context for this bug is in [1].  The basic gist is that I need to
> preserve extended attributes to get the proper capabilities on
> "/bin/ping" inside a rootfs tarball, so I updated my GNU tar invocation
> to include "--xattrs", "--acls", and "--selinux" (just for good
> measure).
>
> [1]: https://github.com/debuerreotype/debuerreotype/pull/38

It gets worse -- apparently any combination of "--xattrs" (with or
without "--xattrs-include" values) makes GNU tar's output completely
unreproducible (running it on the same directory twice will provide a
different result).

I've noted this in [2], and provided a full `hexdump` in [3].

[2]: https://github.com/debuerreotype/debuerreotype/pull/38#issuecomment-393992413
[3]: https://gist.github.com/tianon/5bbfe30a4e889dcece42b8d210f8c8f9

(I poked lamby on IRC about where to note this for the reproducible
builds project as a whole, and he told me to just append it to this
bug for now.)


♥,
- Tianon
  4096R / B42F 6819 007F 00F8 8E36  4FD4 036A 9C25 BF35 7DD4