[Bug] grass.script.mapcalc: Pseudo-random number generator not seeded for raster calculator

[baharmon]

Describe the bug

Running the raster calculator's with its rand() function in grass.jupyter without setting a seed throws the following error: ERROR: Pseudo-random number generator not seeded. This happens both with and without flag s which should generate a random seed. Setting a seed with the seed parameter works as expected. I think the grass.jupyter wrapper for r.mapcalc has a auto-seeding mechanism of its own introduced before flag s was implemented, but it seems to be broken and conflicts with flag s.

To reproduce

gs.mapcalc("random = rand(0.0,1.0)") throws an error.

Error message

ERROR: Pseudo-random number generator not seeded
---------------------------------------------------------------------------
CalledModuleError                         Traceback (most recent call last)
File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py:143](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py#line=142), in mapcalc(exp, quiet, superquiet, verbose, overwrite, seed, env, **kwargs)
    142 try:
--> 143     write_command(
    144         "r.mapcalc",
    145         file="-",
    146         stdin=e,
    147         env=env,
    148         seed=seed,
    149         quiet=quiet,
    150         superquiet=superquiet,
    151         verbose=verbose,
    152         overwrite=overwrite,
    153     )
    154 except CalledModuleError:

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:686](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py#line=685), in write_command(*args, **kwargs)
    685     sys.stderr.write(stderr)
--> 686 return handle_errors(returncode, None, args, kwargs)

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:372](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py#line=371), in handle_errors(returncode, result, args, kwargs)
    371 module, code = get_module_and_code(args, kwargs)
--> 372 raise CalledModuleError(module=module, code=code, returncode=returncode)

CalledModuleError: Module run `r.mapcalc file=-` ended with an error.
The subprocess ended with a non-zero return code: 1. See errors above the traceback or in the error output.

During handling of the above exception, another exception occurred:

ScriptError                               Traceback (most recent call last)
Cell In[12], line 1
----> 1 gs.mapcalc("random = rand(0.0,1.0)")

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py:155](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py#line=154), in mapcalc(exp, quiet, superquiet, verbose, overwrite, seed, env, **kwargs)
    143     write_command(
    144         "r.mapcalc",
    145         file="-",
   (...)    152         overwrite=overwrite,
    153     )
    154 except CalledModuleError:
--> 155     fatal(
    156         _("An error occurred while running r.mapcalc with expression: %s") % e,
    157         env=env,
    158     )

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:824](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py#line=823), in fatal(msg, env)
    822 global raise_on_error
    823 if raise_on_error:
--> 824     raise ScriptError(msg)
    826 error(msg, env=env)
    827 sys.exit(1)

ScriptError: An error occurred while running r.mapcalc with expression: random = rand(0.0,1.0)

gs.mapcalc("random = rand(0.0,1.0)", flags="s") throws an error.

Error message with flag s

``` ERROR: Pseudo-random number generator not seeded --------------------------------------------------------------------------- CalledModuleError Traceback (most recent call last) File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py:143](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py#line=142), in mapcalc(exp, quiet, superquiet, verbose, overwrite, seed, env, **kwargs) 142 try: --> 143 write_command( 144 "r.mapcalc", 145 file="-", 146 stdin=e, 147 env=env, 148 seed=seed, 149 quiet=quiet, 150 superquiet=superquiet, 151 verbose=verbose, 152 overwrite=overwrite, 153 ) 154 except CalledModuleError:

File /Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:686, in write_command(*args, **kwargs)
685 sys.stderr.write(stderr)
--> 686 return handle_errors(returncode, None, args, kwargs)

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:372](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py#line=371), in handle_errors(returncode, result, args, kwargs)
    371 module, code = get_module_and_code(args, kwargs)
--> 372 raise CalledModuleError(module=module, code=code, returncode=returncode)

CalledModuleError: Module run `r.mapcalc file=-` ended with an error.
The subprocess ended with a non-zero return code: 1. See errors above the traceback or in the error output.

During handling of the above exception, another exception occurred:

ScriptError                               Traceback (most recent call last)
Cell In[10], line 1
----> 1 gs.mapcalc("random = rand(0.0,1.0)", flags="s")

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py:155](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/raster.py#line=154), in mapcalc(exp, quiet, superquiet, verbose, overwrite, seed, env, **kwargs)
    143     write_command(
    144         "r.mapcalc",
    145         file="-",
   (...)    152         overwrite=overwrite,
    153     )
    154 except CalledModuleError:
--> 155     fatal(
    156         _("An error occurred while running r.mapcalc with expression: %s") % e,
    157         env=env,
    158     )

File [/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py:824](http://localhost:8888/Applications/GRASS-8.5.app/Contents/Resources/etc/python/grass/script/core.py#line=823), in fatal(msg, env)
    822 global raise_on_error
    823 if raise_on_error:
--> 824     raise ScriptError(msg)
    826 error(msg, env=env)
    827 sys.exit(1)

ScriptError: An error occurred while running r.mapcalc with expression: random = rand(0.0,1.0)

gs.mapcalc("random = rand(0.0,1.0)", seed=12345) works as expected.

Expected behavior

I expect the rand() function for the raster calculator in grass.jupyter to have a random seed successfully generated by default. Flag s should still work even if it is redundant.

System description

• GRASS GIS version: 8.5