Validate divisor parameters in carb_math to prevent ZeroDivisionError#30
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CharlesCNorton wants to merge 1 commit into
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Validate divisor parameters in carb_math to prevent ZeroDivisionError#30CharlesCNorton wants to merge 1 commit into
CharlesCNorton wants to merge 1 commit into
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carb_glucose_effect divides by carb_ratio and parabolic_percent_absorption_at_time divides by absorption_time without checking them, so a zero or negative value raised an opaque ZeroDivisionError from inside the carb-absorption model instead of rejecting the input. Both are strictly positive physical quantities, so validate them and raise a clear ValueError. Adds tests for the rejection and for the unaffected positive path.
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Summary
Two functions in
carb_math.pydivide by a parameter without validating it:carb_glucose_effect:insulin_sensitivity / carb_ratioparabolic_percent_absorption_at_time:2 / pow(absorption_time, 2)and4 / absorption_timeA zero (or negative)
carb_ratioorabsorption_timetherefore raises an opaqueZeroDivisionErrorfrom inside the carb-absorption model. Because these values come fromcarb-ratio and absorption-time settings, a single bad entry crashes the glucose-effect
calculation instead of surfacing the misconfiguration.
For example:
Change
Both quantities are strictly positive by definition (grams per unit, and minutes), so this
validates them and raises a clear
ValueErrorrather than dividing. Silently substituting avalue was avoided on purpose: in dosing math an incorrect carb effect is worse than an explicit
rejection, so the functions fail loudly on invalid input.
Tests
Adds tests that the guards reject non-positive inputs and that the positive path is unchanged.
The full
tests/test_carb_math.pysuite passes (13 tests).Found by static analysis.