gdal_calc.py: allow "none" or a float for --NoDataValue

[waldner]

What does this PR do?

It allows specifying --NoDataValue=none, which was previously failing due to type=float in the parser.add_argument call.

[rouault]

would you mind adding in autotest/pyscripts/test_gdal_calc.py a test case for --NoDataValue=none ?

[waldner]

Done, though since I'm not familiar with the test suite I'm not sure exactly what's supposed to be tested for --NoDataValue=none, so any correction/suggestion is welcome.
FWIW, the test seems to be passing (https://github.com/waldner/gdal/actions/runs/5026033430/jobs/9013795215#step:16:14186), but it's entirely possible that it's a coincidence and I'm not performing the right checks.

[rouault]

with addition actually checking the nodata value on the output raster like the following (untested) :

Suggested change

	check_file(out[0], input_checksum[0])
	check_file(out[0], input_checksum[0])
	ds = gdal.Open(out[0])
	assert ds.GetRasterBand(1).GetNoDataValue() is None

[waldner]

So perhaps I'll also add another test with --NoDataValue=<actual_float_number> and check that it is also applied, so we can test both none and a real value. Thanks

[waldner]

What about now?

[rouault]

test_gdal_calc_py_4 actually does -NoDataValue=999. It just lacks the testing of it. Would be better to add it there to minimize the number of lines & runtime

[waldner]

Shall I add --NoDataValue=none there as well?

[rouault]

Shall I add --NoDataValue=none there as well?

it's probably OK to let it where you added it

[waldner]

Ok, so hopefully now should be it?

[rouault]

we have formatting rules that fail with your commit https://github.com/OSGeo/gdal/actions/runs/5028424696/jobs/9019121500?pr=7793
to solve them, run

pip install pre-commit
pre-commit install
pre-commit run --all-files

[waldner]

Oops sorry, done.