phacility/phabricator · error · Exception

No custom field key specified.

Error message

No custom field key specified.

What it means

The datasource requires a `key` parameter naming which custom field to offer typeahead options for. If `key` is missing or an empty string, loadResults throws immediately after building the field list.

Source

Thrown at src/infrastructure/customfield/datasource/PhabricatorStandardSelectCustomFieldDatasource.php:49

    if (!$reflection->implementsInterface($interface)) {
      throw new Exception(
        pht(
          'Custom field class "%s" does not implement interface "%s".',
          $class,
          $interface));
    }

    $role = $this->getParameter('role');
    if (!strlen($role)) {
      throw new Exception(pht('No custom field role specified.'));
    }

    $object = newv($class, array());
    $field_list = PhabricatorCustomField::getObjectFields($object, $role);

    $field_key = $this->getParameter('key');
    if (!strlen($field_key)) {
      throw new Exception(pht('No custom field key specified.'));
    }

    $field = null;
    foreach ($field_list->getFields() as $candidate_field) {
      if ($candidate_field->getFieldKey() == $field_key) {
        $field = $candidate_field;
        break;
      }
    }

    if ($field === null) {
      throw new Exception(
        pht(
          'No field with field key "%s" exists for objects of class "%s" with '.
          'custom field role "%s".',
          $field_key,
          $class,
          $role));

View on GitHub (pinned to 5720a38cfe)

Solutions

1. Set `key` to the target field's getFieldKey() value (e.g. 'std:maniphest:priority' style keys for standard fields).
2. Find the exact key by listing the object's fields (field list -> getFields() -> getFieldKey()) or from the field's configuration in Config → Custom Fields.
3. Ensure the code path that computes the key cannot pass an empty string; default it explicitly.

Example fix

// before
$datasource->setParameter('key', '');
// after
$datasource->setParameter('key', 'std:maniphest:priority');

$key = $datasource->getParameter('key');
if (!strlen((string)$key)) {
  throw new Exception('datasource parameter "key" is required');
}

function hasCompleteSelectDatasourceParams($datasource) {
  foreach (array('object', 'role', 'key') as $param) {
    if (!strlen((string)$datasource->getParameter($param))) {
      return false;
    }
  }
  return true;
}

When it happens

Trigger: Wiring the datasource with `object` and `role` but never setting `key`, or passing an empty string because the field key variable was null/typo'd when the parameter array was built.

Common situations: Function-wiring code that derives the key from configuration and silently yields '' when the config entry is missing; copy-paste datasource setup that drops one parameter; key constants renamed between versions.

Related errors

• Custom field class "%s" does not exist.
• Custom field class "%s" does not implement interface "%s".
• No custom field role specified.
• No field with field key "%s" exists for objects of class "%s
• Field "%s" is not a standard select field, nor a proxy of a

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/66e91e962472ba1b. Report an issue: GitHub.