[processing][gdal] Do not escape formula because it's not a path!

[luipir]

Description

numpy formula in gdal_calc processing algoritm is managed as a path and escaped in case having spaces. This escape generate triky error during gdal execution.
Just test the error setting the default formula from "A*2" to "A * 2".

fix promoted inside GeoMove [1] project for Cartolab [2] (A Coruña university)

[1] http://cartolab.udc.es/geomove/
[2] http://cartolab.udc.es

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[luipir]

Please @alexbruy can you give a look?

[nyalldawson]

Is this an issue on master too?

[luipir]

@nyalldawson should be, but gdalcalc is still not available as geoprocess in processing and I hadn't time to integrate it.

[nyalldawson]

@luipir ah, that's a shame -- i wasn't aware there was unported algorithms here

[luipir]

confirmed the error should be the same on qgis3...the code is not changed.
No great experience writing tests for processing classes. In this case I would only test if the parsed --calc formula returned by getConsoleCommands is not changed.

[luipir]

@nyalldawson np I'm not really a processing man, I just realized that it was not available because a collegue here in CartoLab wasn't able to calc a SARVI index with any qgis version. They always have to test on any win version before to notify me any error.

[nyalldawson]

@luipir
For gdal/ogr algorithms the best way is to add tests like this: https://github.com/qgis/QGIS/blob/master/python/plugins/processing/tests/GdalAlgorithmsTest.py#L297

But that's for master, not 2.18.

[luipir]

For gdal/ogr algorithms the best way is to add tests like this: https://github.com/qgis/QGIS/blob/master/python/plugins/processing/tests/GdalAlgorithmsTest.py#L297

But that's for master, not 2.18

wonderfull.. I'll add test and pr to 3.x tomorrow. I just checked if there where tests on 2.18.

[alexbruy]

Thanks.
BTW, why not use native calculator?

[luipir]

@alexbruy because crash qgis with with memory allocation problem with big images with any version and platform (SAGA has the same problem). I didn't check personally but I saw some tests. I can check personally to add more information about these crashes.
In general on win he message was "allocation error".

[luipir]

@nyalldawson I'll check if it would be possible to pass and evaluate dangerous formulas like A*2"; rm * without appropriate escaping. GDAL injection?