hyperledger/fabric · error

expected key %s to encode a value of type Int64, but was %T

Error message

expected key %s to encode a value of type Int64, but was %T

What it means

DeserializeFieldAsInt64 type guard: the lifecycle state at the field key decodes to a StateData oneof that is not Int64, so it cannot be returned as an integer (e.g. a sequence field holding a string).

Source

Thrown at core/chaincode/lifecycle/serializer.go:468

	}
	err = proto.Unmarshal(bin, msg)
	if err != nil {
		return errors.Wrapf(err, "could not unmarshal key %s to %T", FieldKey(namespace, name, field), msg)
	}
	return nil
}

func (s *Serializer) DeserializeFieldAsInt64(namespace, name, field string, state ReadableState) (int64, error) {
	value, err := s.DeserializeField(namespace, name, field, state)
	if err != nil {
		return 0, err
	}
	if value.Type == nil {
		return 0, nil
	}
	oneOf, ok := value.Type.(*lb.StateData_Int64)
	if !ok {
		return 0, errors.Errorf("expected key %s to encode a value of type Int64, but was %T", FieldKey(namespace, name, field), value.Type)
	}
	return oneOf.Int64, nil
}

func (s *Serializer) DeserializeAllMetadata(namespace string, state RangeableState) (map[string]*lb.StateMetadata, error) {
	prefix := fmt.Sprintf("%s/%s/", namespace, MetadataInfix)
	kvs, err := state.GetStateRange(prefix)
	if err != nil {
		return nil, errors.WithMessagef(err, "could not get state range for namespace %s", namespace)
	}
	result := map[string]*lb.StateMetadata{}
	for key, value := range kvs {
		name := key[len(prefix):]
		metadata := &lb.StateMetadata{}
		err = proto.Unmarshal(value, metadata)
		if err != nil {
			return nil, errors.Wrapf(err, "error unmarshalling metadata for key %s", key)
		}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Ensure numeric fields (like sequence) were committed as Int64 values
2. Re-commit the chaincode definition with the correct field type

When it happens

Trigger: Thrown at core/chaincode/lifecycle/serializer.go:468 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/80ebd6e83b0945ff. Report an issue: GitHub.