grass.script.raster: auto-seed rand() when no seed provided#7269
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tmchow wants to merge 2 commits intoOSGeo:mainfrom
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grass.script.raster: auto-seed rand() when no seed provided#7269tmchow wants to merge 2 commits intoOSGeo:mainfrom
tmchow wants to merge 2 commits intoOSGeo:mainfrom
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mapcalc() and mapcalc_start() fail with 'Pseudo-random number generator not seeded' when the expression uses rand() and no explicit seed parameter is passed. Detect rand() in the expression and auto-generate a seed, matching the existing seed='auto' behavior. Fixes OSGeo#5974
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mapcalc("random = rand(0.0,1.0)")fails with "Pseudo-random number generator not seeded" becauser.mapcalcrequires an explicit seed for itsrand()function, but the Python wrapper passesNoneby default.The
seed="auto"path already generates a seed correctly (line 144-145), but users have to know to pass it explicitly. This detectsrand(in the expression string and auto-generates a seed when none is provided, matching the existing auto-seed behavior. Applied to bothmapcalc()andmapcalc_start().The check is a simple substring match on the expression before template substitution. It won't false-positive on variable names containing "rand(" since those would be inside
${}template syntax andrand(with a parenthesis is unambiguous as the r.mapcalc function call.This contribution was developed with AI assistance (Claude Code).
Fixes #5974