BoundaryML/baml · error

unexpected type for calls count: %T

Error message

unexpected type for calls count: %T

What it means

CallsCount() type-asserts the bridge result of the 'calls_count' method to Go int; when the runtime returns any other type (e.g. int64, float64, or nil) the assertion fails and this error is thrown. It protects callers from silent numeric-type drift across the runtime boundary.

Source

Thrown at engine/language_client_go/pkg/rawobjects_function_log.go:119

	}

	response, ok := result.(string)
	if !ok {
		return "", fmt.Errorf("unexpected type for raw LLM response: %T", result)
	}

	return response, nil
}

func (f *functionLog) CallsCount() (int, error) {
	result, err := raw_objects.CallMethod(f, "calls_count", nil)
	if err != nil {
		return 0, fmt.Errorf("failed to get calls count: %w", err)
	}

	count, ok := result.(int)
	if !ok {
		return 0, fmt.Errorf("unexpected type for calls count: %T", result)
	}

	return count, nil
}

func (f *functionLog) Calls() ([]LLMCall, error) {
	result, err := raw_objects.CallMethod(f, "calls", nil)
	if err != nil {
		return nil, fmt.Errorf("failed to get calls: %w", err)
	}

	result_cast := result.([]raw_objects.RawPointer)
	calls := make([]LLMCall, len(result_cast))

	for i, call := range result_cast {
		calls[i] = call.(LLMCall)
	}

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Check %T in the error to see the actual numeric type returned
2. Convert the bridge's number type (e.g. int64 or float64) explicitly before or after the assertion
3. Align the bridge marshaling config so numbers decode as int

Example fix

// before
count, ok := result.(int)
if !ok {
    return 0, fmt.Errorf("unexpected type for calls count: %T", result)
}
// after
var count int
switch v := result.(type) {
case int:
    count = v
case int64:
    count = int(v)
case float64:
    count = int(v)
default:
    return 0, fmt.Errorf("unexpected type for calls count: %T", result)
}

func asInt(v any) (int, bool) {
    switch n := v.(type) {
    case int:
        return n, true
    case int64:
        return int(n), true
    case float64:
        return int(n), true
    }
    return 0, false
}

count, err := flog.CallsCount()
if err != nil {
    if strings.Contains(err.Error(), "unexpected type for calls count") {
        return 0, fmt.Errorf("runtime returned non-int count: %w", err)
    }
    return 0, err
}

When it happens

Trigger: Calling FunctionLog.CallsCount() when the remote 'calls_count' method returns a numeric type other than Go int (int64/float64 from the marshaling layer) or nil.

Common situations: JSON/IPC marshaling that decodes numbers as float64 or int64 instead of int; runtime languages with unbounded integers returning bigint-like values; count unset so nil is returned.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• unexpected type for raw LLM response: %T
• unexpected type for class type: %T
• unexpected type for class property builders: %T
• unexpected type for class property builder: %T
• unexpected type for class property type: %T

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/fbcdfd2078ccbb0f. Report an issue: GitHub.