Re: .deb format: let's use 0.939, zstd, drop bzip2

[Ansgar Burchardt <ansgar@debian.org>]

Ian Jackson writes:
> Ansgar writes ("Re: .deb format: let's use 0.939, zstd, drop bzip2"):
>> `ar` needs to be replaced for the file size limitation mentioned in the
>> initial mail: ar represents file size as a 10 digit decimal number[1]
>> which limits the members (control.tar.*, data.tar.*) to ~10G.
> ...
>> Replacing `ar` is an incompatible format change.  So if we already do
>> an incompatible change, it is an appropriate time to bundle any other
>> incompatible changes (if there are any).  That is why I suggested that
>> it might be useful to also replace the `tar` archives with another
>> format.
>
> As has been pointed out, we have done many incompatible format
> changes.  Every new compression algorithm is one.  It isn't really a
> big problem, when managed properly.
>
> So I strongly disagree.  The archive size limit is getting more and
> more annoying.  We should not let fixing that be entangled with some
> random other nice-to-haves.

Changing container formats is a more invasive change than just
compression algorithms (of which there are already several anyway);
I believe it is a bad idea to create too many new formats that
would require long-term support in dpkg.

Ansgar