Alter validation when using inline entity form

Question

Is it possible to alter the validation function when using inline_entity_form ?

Here is an example module that I'm using where I use devel to validate if I can hook into drupals and IEF validate functions (as pointed out by Shawn Conn).

function mymodule_inline_entity_form_entity_form_alter(&$entity_form, &$form_state)
{
  $entity_form['#element_validate'] = array('mymodule_inline_entity_form_entity_form_validate');
}


function mymodule_inline_entity_form_entity_form_validate(&$entity_form, &$form_state)
{
  // No effect
  form_set_error('field_price', '!Validate');
  form_set_error('field_bucket_list', '!Validate');
}

I have one content type which has a title and a decimal field called field_price and a second type which has the IEF field (called field_bucket_list).

Answer 1

Yes, IEF calls drupal_alter() after upon building a form. This enables any custom module to invoke hook_inline_entity_form_entity_form_alter() to alter it.

/**
 * Implements hook_inline_entity_form_entity_form_alter().
 */
function MYMODULE_inline_entity_form_entity_form_alter(&$entity_form, &$form_state) {
  // Replace validation callback.
  $entity_form['#element_validate'] = array(
    'MYMODULE_inline_entity_form_entity_form_validate'
  );
}

function MYMODULE_inline_entity_form_entity_form_validate(&$entity_form, &$form_state) {
  // @TODO: Add extra validation in front of IEF validation handler.
  inline_entity_form_entity_form_validate($entity_form, $form_state);
}

Answer 2

At last I got it to work. Here is the final code where the error was that I did not fully understand how to use form_set_error to point at the field I wanted to validate.

function mymodule_inline_entity_form_entity_form_alter(&$entity_form, &$form_state)
{
  $entity_form['#element_validate'] = array('mymodule_inline_entity_form_entity_form_validate');
}


function mymodule_inline_entity_form_entity_form_validate(&$entity_form, &$form_state)
{
  form_set_error('field_bucket_list][und][form][field_price', '!Validate');
  inline_entity_form_entity_form_validate($entity_form, $form_state);
}

The field I wanted to validate is field_price and is located as values->field_bucket_list->und->form->field_price in $form_state, which I got from using Devel.