BoundaryML/baml · error

division by zero at

Error message

division by zero at {:?}

What it means

The `/` division operator checks the divisor and bails when it is zero — for both integer division (b == 0) and float division (b == 0.0). The interpreter converts the error to a runtime failure at the expression's source position rather than producing infinity or NaN.

Solutions

1. Check the divisor for zero before dividing and return a sentinel/default value for the zero case
2. Guarantee denominators come from validated, nonzero sources
3. For averages over possibly-empty lists, special-case the empty case
4. Catch the runtime error around evaluation and handle it

Example fix

// before
let avg = total / count;   // count can be 0
// after
let avg = if (count == 0) { 0.0 } else { total / count };

if (divisor === 0 || divisor === 0.0) { throw new Error('guard: divisor is zero, skip division'); }

function isNonZeroNumber(v) { return typeof v === 'number' && v !== 0; }

try { result = a / b; } catch (e) { if (String(e).includes('division by zero')) { result = defaultValue; } else { throw e; } }

When it happens

Trigger: Evaluating `a / b` where b is the integer 0 or float 0.0, including when b is a computed value or variable that happens to be zero (e.g. an empty-sum denominator, a count of zero items).

Common situations: Computing averages/ratios over empty collections (count = 0); user-supplied or LLM-supplied divisors that can be zero; percentages with total = 0.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• division by zero in /= operator
• modulo by zero in %= operator
• expected value, found function
• for loop requires iterable (list)
• instanceof requires a class instance on the left side at

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/a8572a960fb24660. Report an issue: GitHub.

Appendix: source

Thrown at engine/baml-compiler/src/thir/interpret.rs:2401

        BinaryOperator::Mul => match (left_val.clone(), right_val.clone()) {
            (BamlValueWithMeta::Int(a, _), BamlValueWithMeta::Int(b, _)) => {
                BamlValueWithMeta::Int(a * b, meta.clone())
            }
            (BamlValueWithMeta::Float(a, _), BamlValueWithMeta::Float(b, _)) => {
                BamlValueWithMeta::Float(a * b, meta.clone())
            }
            (BamlValueWithMeta::Int(a, _), BamlValueWithMeta::Float(b, _)) => {
                BamlValueWithMeta::Float((a as f64) * b, meta.clone())
            }
            (BamlValueWithMeta::Float(a, _), BamlValueWithMeta::Int(b, _)) => {
                BamlValueWithMeta::Float(a * (b as f64), meta.clone())
            }
            _ => bail!("unsupported types for * operator at {:?}", meta.0),
        },
        BinaryOperator::Div => match (left_val.clone(), right_val.clone()) {
            (BamlValueWithMeta::Int(a, _), BamlValueWithMeta::Int(b, _)) => {
                if b == 0 {
                    bail!("division by zero at {:?}", meta.0);
                }
                BamlValueWithMeta::Float((a as f64) / (b as f64), meta.clone())
            }
            (BamlValueWithMeta::Float(a, _), BamlValueWithMeta::Float(b, _)) => {
                if b == 0.0 {
                    bail!("division by zero at {:?}", meta.0);
                }
                BamlValueWithMeta::Float(a / b, meta.clone())
            }
            (BamlValueWithMeta::Int(a, _), BamlValueWithMeta::Float(b, _)) => {
                if b == 0.0 {
                    bail!("division by zero at {:?}", meta.0);
                }
                BamlValueWithMeta::Float((a as f64) / b, meta.clone())
            }
            (BamlValueWithMeta::Float(a, _), BamlValueWithMeta::Int(b, _)) => {
                if b == 0 {
                    bail!("division by zero at {:?}", meta.0);

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