--ignore-rest does not work correctly

[ihnorton]

As far as I understand, it should allow to pass further arguments only to the launched binary, but:

``` sliceruser@8192a65779e5:~/Slicer-4.9.0-2018-10-14-linux-amd64$ ./Slicer --launch ./bin/python-real --ignore-rest -h Usage Slicer [options]

Options
--launcher-help Display help
--launcher-version Show launcher version information
--launcher-verbose Verbose mode
--launch Specify the application to launch
--launcher-detach Launcher will NOT wait for the application to finish
--launcher-no-splash Hide launcher splash
--launcher-timeout Specify the time in second before the launcher kills the application. -1 means no timeout (default: -1)
--launcher-load-environment Specify the saved environment to load.
--launcher-dump-environment Launcher will print environment variables to be set, then exit
--launcher-show-set-environment-commands Launcher will print commands suitable for setting the parent environment (i.e. using 'eval' in a POSIX shell), then exit
--launcher-additional-settings Additional settings file to consider
--launcher-additional-settings-exclude-groups Comma separated list of settings groups that should NOT be overwritten by values in User and Additional settings. For example: General,Application,ExtraApplicationToLaunch
--launcher-ignore-user-additional-settings Ignore additional user settings
--launcher-generate-exec-wrapper-script Generate executable wrapper script allowing to set the environment
--launcher-generate-template Generate an example of setting file
Unknown option: --
usage: ./bin/python-real [option] ... [-c cmd | -m mod | file | -] [arg] ...
Try `python -h' for more information.
sliceruser@8192a65779e5:~/Slicer-4.9.0-2018-10-14-linux-amd64$ ./Slicer --launch ./bin/python-real -- -h
Usage
Slicer [options]

Options
--launcher-help Display help
--launcher-version Show launcher version information
--launcher-verbose Verbose mode
--launch Specify the application to launch
--launcher-detach Launcher will NOT wait for the application to finish
--launcher-no-splash Hide launcher splash
--launcher-timeout Specify the time in second before the launcher kills the application. -1 means no timeout (default: -1)
--launcher-load-environment Specify the saved environment to load.
--launcher-dump-environment Launcher will print environment variables to be set, then exit
--launcher-show-set-environment-commands Launcher will print commands suitable for setting the parent environment (i.e. using 'eval' in a POSIX shell), then exit
--launcher-additional-settings Additional settings file to consider
--launcher-additional-settings-exclude-groups Comma separated list of settings groups that should NOT be overwritten by values in User and Additional settings. For example: General,Application,ExtraApplicationToLaunch
--launcher-ignore-user-additional-settings Ignore additional user settings
--launcher-generate-exec-wrapper-script Generate executable wrapper script allowing to set the environment
--launcher-generate-template Generate an example of setting file
./bin/python-real: can't open file '-h': [Errno 2] No such file or directory
sliceruser@8192a65779e5:~/Slicer-4.9.0-2018-10-14-linux-amd64$ ./Slicer --launch ./bin/python-real -h
Usage
Slicer [options]

Options
--launcher-help Display help
--launcher-version Show launcher version information
--launcher-verbose Verbose mode
--launch Specify the application to launch
--launcher-detach Launcher will NOT wait for the application to finish
--launcher-no-splash Hide launcher splash
--launcher-timeout Specify the time in second before the launcher kills the application. -1 means no timeout (default: -1)
--launcher-load-environment Specify the saved environment to load.
--launcher-dump-environment Launcher will print environment variables to be set, then exit
--launcher-show-set-environment-commands Launcher will print commands suitable for setting the parent environment (i.e. using 'eval' in a POSIX shell), then exit
--launcher-additional-settings Additional settings file to consider
--launcher-additional-settings-exclude-groups Comma separated list of settings groups that should NOT be overwritten by values in User and Additional settings. For example: General,Application,ExtraApplicationToLaunch
--launcher-ignore-user-additional-settings Ignore additional user settings
--launcher-generate-exec-wrapper-script Generate executable wrapper script allowing to set the environment
--launcher-generate-template Generate an example of setting file
usage: ./bin/python-real [option] ... [-c cmd | -m mod | file | -] [arg] ...
Options and arguments (and corresponding environment variables):
-B : don't write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x
-c cmd : program passed in as string (terminates option list)
-d : debug output from parser; also PYTHONDEBUG=x
-E : ignore PYTHON* environment variables (such as PYTHONPATH)
-h : print this help message and exit (also --help)
-i : inspect interactively after running script; forces a prompt even
if stdin does not appear to be a terminal; also PYTHONINSPECT=x
-m mod : run library module as a script (terminates option list)
-O : optimize generated bytecode slightly; also PYTHONOPTIMIZE=x
-OO : remove doc-strings in addition to the -O optimizations
-R : use a pseudo-random salt to make hash() values of various types be
unpredictable between separate invocations of the interpreter, as
a defense against denial-of-service attacks
-Q arg : division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew
-s : don't add user site directory to sys.path; also PYTHONNOUSERSITE
-S : don't imply 'import site' on initialization
-t : issue warnings about inconsistent tab usage (-tt: issue errors)
-u : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x
see man page for details on internal buffering relating to '-u'
-v : verbose (trace import statements); also PYTHONVERBOSE=x
can be supplied multiple times to increase verbosity
-V : print the Python version number and exit (also --version)
-W arg : warning control; arg is action:message:category:module:lineno
also PYTHONWARNINGS=arg
-x : skip first line of source, allowing use of non-Unix forms of #!cmd
-3 : warn about Python 3.x incompatibilities that 2to3 cannot trivially fix
file : program read from script file

•  : program read from stdin (default; interactive mode if a tty)
  

arg ...: arguments passed to program in sys.argv[1:]

Other environment variables:
PYTHONSTARTUP: file executed on interactive startup (no default)
PYTHONPATH : ':'-separated list of directories prefixed to the
default module search path. The result is sys.path.
PYTHONHOME : alternate directory (or :<exec_prefix>).
The default module search path uses /pythonX.X.
PYTHONCASEOK : ignore case in 'import' statements (Windows).
PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr.
PYTHONHASHSEED: if this variable is set to 'random', the effect is the same
as specifying the -R option: a random value is used to seed the hashes of
str, bytes and datetime objects. It can also be set to an integer
in the range [0,4294967295] to get hash values with a predictable seed.

</details>

[ihnorton]

Related to #52.

It would be nice to have an implicit mode like --launch prog <all these arguments are passed to prog>. I guess this would be a breaking change, so we would need to use something other than --launch.

[jcfr]

-h is a "special case", looking at the SlicerLauncherSettings.ini file we have:

[General]
[...]
additionalLauncherHelpShortArgument=-h
additionalLauncherHelpLongArgument=--help
[...]

This means we should probably be ignore the additionalLauncherHelpShortArgument and additionalLauncherHelpLongArgument value when --launch is passed ?

Also, most of the argument to the launcher are namespaced (starts with --launcher-*), I think issue is specific to -h and --help.

The following calls work:

$ ./Slicer --launch ../python-install/bin/python --version
2.7.13

$ ./Slicer --launch python --version
2.7.13

$ ./Slicer --launch ../python-install/bin/python -c "import os; print(os.__file__)"
/home/jcfr/Projects/Slicer-Qt5-VTK9-RelWithDebInfo/python-install/lib/python2.7/os.pyc

$ ./Slicer --launch python -c "import os; print(os.__file__)"
/home/jcfr/Projects/Slicer-Qt5-VTK9-RelWithDebInfo/python-install/lib/python2.7/os.pyc