bug#29235: 26.0.50; tar.xz broken

[Devon Sean McCullough]

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.

                Peace
                        --Devon

P.S. Transcript follows:

$ type xz
bash: type: xz: not found
$ type tar
tar is /usr/bin/tar
$ tar -h
tar(bsdtar): manipulate archive files
First option must be a mode specifier:
  -c Create  -r Add/Replace  -t List  -u Update  -x Extract
Common Options:
  -b #  Use # 512-byte records per I/O block
  -f <filename>  Location of archive
  -v    Verbose
  -w    Interactive
Create: tar -c [options] [<file> | <dir> | @<archive> | -C <dir> ]
  <file>, <dir>  add these items to archive
  -z, -j, -J, --lzma  Compress archive with gzip/bzip2/xz/lzma
  --format {ustar|pax|cpio|shar}  Select archive format
  --exclude <pattern>  Skip files that match pattern
  -C <dir>  Change to <dir> before processing remaining files
  @<archive>  Add entries from <archive> to output
List: tar -t [options] [<patterns>]
  <patterns>  If specified, list only entries that match
Extract: tar -x [options] [<patterns>]
  <patterns>  If specified, extract only entries that match
  -k    Keep (don't overwrite) existing files
  -m    Don't restore modification times
  -O    Write entries to stdout, don't restore to disk
  -p    Restore permissions (including ACLs, owner, file flags)
bsdtar 2.8.3 - libarchive 2.8.3

$ cd /tmp
$ echo foo > bar
$ tar -cJ bar > bar.tar.xz
$ tar -tv < bar.tar.xz
-rw-r--r--  0 devon  wheel       4 Nov  9 14:43 bar
$ tar -xO bar < bar.tar.xz
foo

$ cat > test.el <<.
(print emacs-version)
(dolist (b (buffer-list))
  (with-current-buffer b
    (print b)
    (print (buffer-string))))
.
$ Emacs --batch -Q -q --eval '(setq debug-on-error t)' /tmp/bar.tar.xz --load 
test.el
Warning: arch-dependent data dir 
'/Users/build/workspace/Emacs-Multi-Build/label/mavericks/emacs-source/nextstep/Emacs.app/Contents/MacOS/libexec/':
 No such file or directory
XZ uncompressing bar.tar.xz...
Parsing tar file...
Parsing tar file...done

"26.0.50"

#<buffer *scratch*>

""

#<buffer  *Minibuf-0*>

""

#<buffer *Messages*>

"Warning: arch-dependent data dir 
\342\200\231/Users/build/workspace/Emacs-Multi-Build/label/mavericks/emacs-source/nextstep/Emacs.app/Contents/MacOS/libexec/\342\200\231:
 No such file or directory

XZ uncompressing bar.tar.xz...
Parsing tar file...done
"

#<buffer  *code-conversion-work*>

"/private/tmp/test.el"

#<buffer bar.tar.xz>

"
"

#<buffer  *jka-compr-error*>

"Error while executing \"xz -c -q -d < /tmp/bar.tar.xz\"

/bin/sh: xz: command not found
"

#<buffer  *tar-data bar.tar.xz*>

""

#<buffer  *load*>

"(print emacs-version)
(dolist (b (buffer-list))
  (with-current-buffer b
    (print b)
    (print (buffer-string))))
"

In GNU Emacs 26.0.50 (build 1, x86_64-apple-darwin13.4.0, NS appkit-1265.21 
Version 10.9.5 (Build 13F1911))
 of 2017-06-07 built on builder10-9.local
Windowing system distributor 'Apple', version 10.3.1404
Recent messages:
Checking 57 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/eshell...
Checking 70 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/erc...
Checking 34 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/emulation...
Checking 174 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/emacs-lisp...
Checking 24 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/cedet...
Checking 57 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/calendar...
Checking 87 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/calc...
Checking 103 files in 
/Applications/Emacs-2017f07w.app/Contents/Resources/lisp/obsolete...
Checking for load-path shadows...done
Undo! [2 times]
user-error: No further undo information
Configured using:
 'configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp' --with-modules'

Configured features:
NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Shell

Minor modes in effect:
  erc-list-mode: t
  erc-menu-mode: t
  erc-autojoin-mode: t
  erc-ring-mode: t
  erc-networks-mode: t
  erc-pcomplete-mode: t
  erc-track-mode: t
  erc-match-mode: t
  erc-button-mode: t
  erc-fill-mode: t
  erc-stamp-mode: t
  erc-netsplit-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rfc822 mml mml-sec epa epg
epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils pulse eieio-opt
speedbar sb-image ezimage dframe find-func erc-list erc-menu erc-join
erc-ring erc-networks erc-pcomplete erc-track erc-match erc-button
wid-edit erc-fill erc-stamp erc-netsplit erc-goodies erc erc-backend
erc-compat pcmpl-unix pcmpl-gnu tar-mode jka-compr view dired-aux
tramp-cache ange-ftp tramp-ftp tramp tramp-compat tramp-loaddefs
trampver shell pcomplete parse-time format-spec dired dired-loaddefs
cl-indent network-stream puny nsm subr-x auth-source password-cache
starttls tls gnutls debug ibuf-ext ibuffer ibuffer-loaddefs seq lpr
mule-diag misearch multi-isearch cl-print help-fns radix-tree
slime-fancy slime-trace-dialog slime-fontifying-fu slime-package-fu
slime-references slime-compiler-notes-tree slime-scratch
slime-presentations advice bridge slime-macrostep macrostep
slime-mdot-fu slime-enclosing-context slime-fuzzy slime-fancy-trace
slime-fancy-inspector slime-c-p-c slime-editing-commands slime-autodoc
slime-repl elp slime-parse slime derived cl-extra help-mode edmacro
kmacro lisp-mnt gud apropos compile etags xref cl-seq project eieio
byte-opt bytecomp byte-compile cconv eieio-core eieio-loaddefs arc-mode
archive-mode noutline outline easy-mmode easymenu pp comint ansi-color
ring hyperspec thingatpt browse-url slime-autoloads cl-macs cl gv
cl-loaddefs cl-lib time-date tooltip eldoc electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel term/ns-win ns-win ucs-normalize
mule-util term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote kqueue cocoa ns multi-tty make-network-process emacs)

Memory information:
((conses 16 385031 15149)
 (symbols 48 32323 0)
 (miscs 40 177 721)
 (strings 32 58176 9683)
 (string-bytes 1 1721858)
 (vectors 16 47494)
 (vector-slots 8 840851 12047)
 (floats 8 99 452)
 (intervals 56 4661 418)
 (buffers 976 31))