bug#29235: 26.0.50; tar.xz broken

[Eli Zaretskii]

> From: Devon Sean McCullough <Emacs-Hacker2017@jovi.net>
> Date: Thu, 9 Nov 2017 16:41:34 -0500
> 
> Emacs fails to open tar.xz files
> 
>       Error while executing "xz -c -q -d < /tmp/bar.tar.xz"
>       /bin/sh: xz: command not found
> 
> Note that MacOSX lacks xz but has tar
> which automagically decompresses xz.

Having tar or bsdtar does not help in this case, because what Emacs
needs is the uncompressed tar file (which it will then display in
tar-mode).  By contrast, bsdtar will unpack the archive completely,
writing the files to the disk.  AFAIK, tar and bsdtar don't have an
option to just uncompress the archive, or did I miss something?

So yes, you really need top install xz for this feature to work.