[CMake] [BUG?] Setting environment variables with embedded blanks does not work with VERBATIM

[Alan W. Irwin]

I normally avoid using embedded blanks in directory names on Linux (Debian
Lenny, CMake-2.8.0), but I am trying to help out one of my colleagues who is
using embedded blanks in directory names in the Windows case.  He does have
access to bash via win-bash.  However, before I can replicate his issue, I
have to sort out the Linux CMake issues with embedded blanks, and any help
with that would be much appreciated.

The PLplot test system assumes bash (either normal bash or win-bash) is
available and uses environment variables specified on the command line. Here
is a simple example of this.

COMMAND DUMMY=${CMAKE_CURRENT_BINARY_DIR} printenv DUMMY

This works fine if there are no embedded blanks in CMAKE_CURRENT_BINARY_DIR,
and the bash result of the above cmake COMMAND in a custom target is

DUMMY=/home/software/plplot_svn/HEAD/build_dir/examples printenv DUMMY

with the expected output

/home/software/plplot_svn/HEAD/build_dir/examples

However, if CMAKE_CURRENT_BINARY_DIR has an embedded blank, e.g.,

/home/software/plplot svn/HEAD/build_dir/examples

then the resulting generated command is

"DUMMY=/home/software/plplot svn/HEAD/build_dir/examples" printenv DUMMY

which gives the bash error

/bin/sh: DUMMY=/home/software/plplot svn/HEAD/build_dir/examples: No such
file or directory

because bash does not like quotes around variable assignment statements.

To solve this issue, VERBATIM should simply put the quotes around everything
after the equal sign when there are embedded blanks, e.g.,

DUMMY="/home/software/plplot svn/HEAD/build_dir/examples" printenv DUMMY

which I have verified works fine on the bash command line.  If the CMake
developers here agree that is a VERBATIM bug, I will write up the
appropriate bug report in the cmake bug tracker to keep track of the issue.

The non-VERBATIM case gives the same bad result (quotes around the variable
assignment).  However, I did find a clumsy workaround in that case which
is to put something innocuous that does not have an embedded blank as
the first part of the command, e.g.,

COMMAND DUMMY= DUMMY=${CMAKE_CURRENT_BINARY_DIR} printenv DUMMY

For some reason, in the non-VERBATIM case only the first blank-delimited
part of the command is always quoted if it has an embedded blank and
subsequent parts of the command use an escaped blank instead.  So the above
COMMAND in the non-VERBATIM case results in the generated command,

DUMMY= DUMMY=/home/software/plplot\ svn/HEAD/build_dir/examples printenv DUMMY

which works fine.

Until the VERBATIM bug gets fixed, is there some better way (other than the
above clumsy non-VERBATIM workaround) to deal with embedded blanks in bash
variable assignment statements?

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); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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Linux-powered Science
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