Validation radio custom fields on civicrm_validateForm hook does not work

Question

I have a custom field on contact in radio type format, not required field. I'd like to set up custom error on this field by using hook_civicrm_validateForm when the field is null.

// hook in extension
function hook_civicrm_validateForm($formName, &$fields, &$files, &$form, &$errors) {}

$fields array doesn't contain a key for this custom field. After setting $error['custom_xx'] the form is reloaded without displaying the error.

What I found:

$form->_elementIndex contains all needed keys, including this for radio. So I suppose this is not a problem.

I think that problem is caused by using _submitValues[] as a list of fields because _submitValues doesn't contain null radio custom fields:

// CRM_Core_Form->validate():
CRM_Utils_Hook::validateForm(
  get_class($this),
  $this->_submitValues,
  $this->_submitFiles,
  $this,
  $hookErrors
);

// my hook
function example_civicrm_validateForm($formName, &$fields, &$files, &$form, &$errors) {
  if ($formName == 'CRM_Contact_Form_Contact') {
    if (in_array('AA', $fields['contact_sub_type'])) {
      $fieldIndex = 'custom_70-1';
      if (!in_array($fieldIndex, array_keys($fields)) || !$fields[$fieldIndex]) {
        $errors[$fieldIndex] = 'For AA contact type this field is required';
      }
    }
  }
}

Edit:

Here is my workaround - add missing keys to _submitValues[] array https://github.com/caltha-eu/civicrm-core/commit/b4ee607334f3f091bffc2c32a87d862e4a3d7493

foreach ($this->_elementIndex as $elementIndex => $index) {
  if (!in_array($elementIndex, array_keys($this->_submitValues))) {
    $this->_submitValues[$elementIndex] = NULL;
  }
}

Answer 1

Make the field required all the time. Add another choice to the radio called "Not Required". In your validate hook check if the contact subtype is AA and if they chose Not Required set the $errors variable on your radio field to show your error. Since you made it a required field it will be in the fields array.

For inline edit the formName is CRM_Contact_Form_Inline_CustomData and you will need to look up the contact subtype using the api, e.g. civicrm_api3('Contact', 'get'...). Use the contact id from $fields['cid']. (Go to /civicrm/api in your browser - it's very handy for getting the api syntax correct.)

Also note your custom field in edit mode will have a different name. It won't be custom_70-1 it will be custom_70-3838 or something like that, so you'll need to either look it up from $form first (e.g. in the groupTree element) or do something like loop through the $fields keys and compare substr($key, 0, 9) == 'custom_70'.