[GRASS-dev] Handling of Python scripts on MS Windows

[Markus Metz]

On Mon, Feb 10, 2014 at 8:29 PM, Vaclav Petras <wenzeslaus at gmail.com> wrote:
>
>
>
> On Mon, Feb 10, 2014 at 2:17 PM, Markus Metz <markus.metz.giswork at gmail.com>
> wrote:
>>
>> On Mon, Feb 10, 2014 at 6:44 PM, Vaclav Petras <wenzeslaus at gmail.com>
>> wrote:
>> >
>> >
>> >
>> > On Mon, Feb 10, 2014 at 8:41 AM, Markus Metz
>> > <markus.metz.giswork at gmail.com>
>> > wrote:
>> >>
>> >> On Mon, Feb 10, 2014 at 12:04 PM, Moritz Lennert
>> >> <mlennert at club.worldonline.be> wrote:
>> >> > On 10/02/14 11:46, Markus Metz wrote:
>> >> >>
>> >> >> On Mon, Feb 10, 2014 at 11:26 AM, Helmut Kudrnovsky <hellik at web.de>
>> >> >> wrote:
>> >> >>>>>
>> >> >>>>> Therefore we need
>> >> >>>>> hard-coded special treatment for shell and Python scripts in
>> >> >>>>> order
>> >> >>>>> to
>> >> >>>>> make sure that the correct interpreter is used.
>> >> >>>
>> >> >>>
>> >> >>>> Just for my understanding: When you say hard-coded special
>> >> >>>> treatment
>> >> >>>> for
>> >> >>>> shell scripts, are you speaking about the .bat files ?
>> >> >>>
>> >> >>>
>> >> >>> I think yes.
>> >> >>
>> >> >>
>> >> >> Or more generally, any mechanism explicitly using %GRASS_PYTHON%
>> >> >> script.py.
>> >> >
>> >> >
>> >> > But as far as I've seen, this might not be sufficient since this only
>> >> > indicates which Python executable to use for launching the Python
>> >> > script,
>> >> > but any library calls linked to that execution will involve the
>> >> > system-wide
>> >> > installed Python. Which is different from bash scripts, where this is
>> >> > not an
>> >> > issue.
>> >>
>> >> GRASS Python scripts are currently executed using the system-wide
>> >> installed Python if it exists. No attempt has been made to explicitly
>> >> use GRASS_PYTHON, therefore it is not possible to say if the system's
>> >> Python would really be completely ignored.
>> >
>> >
>> > If I remember correctly, Python scripts were not working from Python
>> > scripts, they were working from command line.
>>
>> Which command line? If you used the msys command line, it should work
>> because within msys, the embedded GRASS_PYTHON version is readily
>> available:
>>
>> GRASS 7.0.svn> which python
>> /c/Programme/GRASS GIS 7.0.svn/extrabin/python.exe
>>
>> > And we were not able to
>> > explain why the right Python (or Python DLL) is used at one point but
>> > not
>> > the other.
>>
>> If you used the GUI, you are outside the msys shell and the system's
>> Python is used. Scripts invoke other GRASS modules with
>> grass.run_command() which uses the system's script interpreter if the
>> module is a script.
>>
> So, msys is able to configure our Python in the way that it is usable
> without interference with the system Python.

Maybe, but I did not test it thoroughly. Anyway, G7 is supposed to run
without the msys console which is optional.

Markus M