Support for .tar.xz in the url stanza

[rednoah]

I'd like support for .tar.xz (and maybe .tar.bz2) archives in the url stanza.

Newer versions of the tar command implicitly support xz compression so it may already be supported. In which case the url stanza manual should be update to reflect that fact.

[SeanSith]

@rednoah The default tar implementation on MacOS X (even in Yosemite) does not currently support XZ compression. I've updated the documentation to show .tbz2 support, but I'm leaving a decision on the XZ support up to Core.

[tjnycum]

What about supporting .tar.xz however homebrew does? (They're working with the same tar, right?)

[DomT4]

We use a Homebrew-delivered xz.

[tjnycum]

Ah, that's right. I remember learning about that on-the-fly addition of an xz dependency a few months ago.

So how about unxzing the .tar.xz's before calling tar? Whenever a .tar.xz will have to be unpacked (e.g. brew cask installing a cask that has a such an URL), check for xz in the path. If it's not there, brew install xz and proceed (or display an error about it requiring xz if that fails). Yes, it represents an additional dependency, but it would only affect users who actually needed it for a cask they tried to install and who didn't already have it installed anyway.

[vitorgalvao]

@rednoah Have you tried unar? Doesn’t that work?

[vitorgalvao]

Closing on account on no reply, since one is needed to proceed.