vitessio/vitess · error

panic(err)

Error message

panic(err)

What it means

EvalResult.MustBoolean asserts that the result can be strictly converted to a boolean; if ToBooleanStrict returns an error the Must* contract panics with that error. Must* methods are for call sites that already know the value is boolean-coercible.

Source

Thrown at go/vt/vtgate/evalengine/eval_result.go:86

// TupleValues allows for retrieval of the value we expose for public consumption
func (er EvalResult) TupleValues() []sqltypes.Value {
	// TODO: Make this collation-aware
	switch v := er.v.(type) {
	case *evalTuple:
		result := make([]sqltypes.Value, 0, len(v.t))
		for _, val := range v.t {
			result = append(result, evalToSQLValue(val))
		}
		return result
	default:
		return nil
	}
}

func (er EvalResult) MustBoolean() bool {
	b, err := er.ToBooleanStrict()
	if err != nil {
		panic(err)
	}
	return b
}

func (er EvalResult) ToBoolean() bool {
	return evalIsTruthy(er.v) == boolTrue
}

// ToBooleanStrict is used when the casting to a boolean has to be minimally forgiving,
// such as when assigning to a system variable that is expected to be a boolean
func (er EvalResult) ToBooleanStrict() (bool, error) {
	switch v := er.v.(type) {
	case *evalInt64:
		switch v.i {
		case 0:
			return false, nil
		case 1:
			return true, nil

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Replace MustBoolean with ToBooleanStrict and handle the error
2. Only call MustBoolean on results known to come from boolean-producing expressions
3. Add a type/type check on the underlying value before calling

Example fix

// before
b := result.MustBoolean()
// after
b, err := result.ToBooleanStrict()
if err != nil {
    return vterrors.Wrapf(err, "expected boolean result")
}

// check strict convertibility first
if _, err := er.ToBooleanStrict(); err != nil {
    return vterrors.Wrapf(err, "result is not a boolean")
}

func isStrictBoolean(er EvalResult) bool {
    _, err := er.ToBooleanStrict()
    return err == nil
}

func safeMustBoolean(er EvalResult) (b bool, err error) {
    defer func() {
        if r := recover(); r != nil {
            err = vterrors.Errorf(vtrpcpb.Code_INTERNAL, "MustBoolean: %v", r)
        }
    }()
    return er.MustBoolean(), nil
}

When it happens

Trigger: Calling MustBoolean on an EvalResult whose underlying value is not strictly boolean — e.g. a string, integer, or NULL result from expression evaluation passed to MustBoolean.

Common situations: Developers using MustBoolean on arbitrary query results instead of checking ToBooleanStrict first; value returned from a comparison changed shape after a refactor.

Related errors

• malformed hex literal from parser
• bad unsigned integer type
• bad type aggregation for signed/unsigned types
• unreachable
• unhandled case: evalIsTruthy

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/6f17dd11e9056c96. Report an issue: GitHub.