[cmake-developers] cmake -E tar not working correctly with xz-compressed tarballs on MSYS

[Alan W. Irwin]

I created an xz-compressed test tarball on Linux using the J option

tar Jcf test.tar.xz ...

On Linux,

cmake -E tar xfz test.tar.xz

unpacks that tarball without issue.

For MSYS (on a Wine-1.6-rc4 platform), that same command hangs
indefinitely.  Wine often does not respond well to ordinary errors so
I used ctrl-C to get out of the hang, and the following message
was displayed on the command line:

unxz: (stdin): File format not recognized

To remove the Wine uncertainty could someone attempt
a similar MSYS experiment on the Microsoft version of
Windows?

However, assuming that verification succeeds, then
that error message is only delivered if you attempt to do something
like (under MSYS)

bash.exe-3.1$ cat non-tar.xz_file |unxz -c > test_file

so I assume that is what cmake is trying to do, and there is some
issue accessing the correct file.

For example, if I execute (under MSYS)

bash.exe-3.1$ cat test.tar.xz |unxz -c >test2.tar

the resulting tarball, test2.tar is fine.

Also, you can create and also unpack xz-compressed tarballs under
MSYS using the J option.

So on MSYS platforms the command-line tools
are working fine for manipulating xz-compressed tarballs, but

cmake -E tar xfz test.tar.xz

fails (and also appears to be using the unxz command-line tool
that is not correctly finding the xz-compressed tarball).

I suspect this is a trivial issue since the xz-related command-line
tools all work on MSYS, but as always the difficult thing to do with
CMake is to find where the issue is occurring.  I starting looking in
Utilities/cmlibarchive/libarchive, but any additional guidance would
be appreciated.

Note, the above MSYS tests were done using the Windows binary version
of cmake-2.8.11.2 that was obtained by

wget "http://www.cmake.org/files/v2.8/cmake-2.8.11.2-win32-x86.zip"
unzip cmake-2.8.11.2-win32-x86.zip

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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