Using xz by default for compression

Mojca Miklavec mojca at
Tue Jan 20 03:21:32 PST 2015

(was: /opt/local/macports/software)

I'm switching to the developers mailing list – I believe the
discussion belongs there more than to the users' list.

On Tue, Jan 20, 2015 at 10:46 AM, Chris Jones wrote:
> On 20/01/15 02:37, Joshua Root wrote:
>> Daniel J. Luke wrote:
>>>> On Jan 19, 2015, at 6:34 AM, René J.V. Bertin wrote:
>>>> What could be an option:
>>>> - use xz instead of bzip2 to compact things a bit more
>>> this would probably be a small change (I think there's support for gzip
>>> and zip already) - but changing your local archive type means you won't get
>>> binary archives.
>> This was true in the past, but no longer. Setting portarchivetype only
>> affects the type of archives that are generated when building locally.
>> Each archive site now has an associated archive type, which happens to
>> be tbz2 for and its mirrors.
>> We do support building txz archives already, and they can happily
>> coexist with downloaded tbz2 ones. The catch is that you have to have
>> the xz port installed to install or activate any txz archives. So the
>> default is not going to change unless/until Apple starts shipping xz
>> with OS X.
> Or... MP starts shipping xz as a requirement, such as is done with TCL. If
> using xv saves more than it takes up (almost certainly the case) it is
> something to consider.

I would support the switch to xz. Yes, MacPorts could ship xz along
with Tcl and ports could check for both tar.xz and tar.bz2 if tar.xz
wasn't found.

If we wanted to change the contents on the servers, the buildbots
wouldn't have to rebuild everything. It's just a matter of writing a
script that recurses through contents and first extract tar.bz2, then
compresses into tar.xz, done.

TeX Live started shipping xz archives and xz + xzdec binary. It can be
build with no external dependencies and takes up a minimal amount of

350K xz.universal-darwin
361K xz.x86_64-darwin
153K xzdec.universal-darwin
162K xzdec.x86_64-darwin

(universal-darwin: ppc + i386 built on 10.5, x86_64 built on 10.6; the
binaries shipped by TL work on all machines from 10.5 on without any
problems, but they could easily be built on Tiger)

A slight disadvantage of xz is that many users still don't know how to
decompress such files, but this argument doesn't apply here since
"port" would do everything automatically for the user.


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