Restrict creation of new taxonomy terms via node form through entity reference filed (autocomplete) for particular user role

Question

I have Entity reference field (taxonomy terms ) in node form.

I have checked the option (Create referenced entities if they don't already exist) so that users can create new taxonomy terms in field of node form i.e.: on creation on node new terms creation is allowed.

Looks like below in Node Form:

But I want to alter this and make restricted to certain roles. So that user with particular role should not be able to create new terms and must select from existing node.

My field is core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EntityReferenceAutocompleteWidget.php

While going thorugh code it seems under :

[#selection_settings] => Array
                        (
                            [target_bundles] => Array
                                (
                                    [topic] => topic
                                )

                            [sort] => Array
                                (
                                    [field] => name
                                    [direction] => asc
                                )

                            [auto_create] => 1
                            [auto_create_bundle] => 
                            [match_operator] => CONTAINS
                        )

[auto_create] => 1 I tried to alter this by adding contain of user role in node form alter, but not its not working the value get changed.

Please suggest !

Update : Please see @ssibal

    drupal config-list field.field.node.link.field_topic2
 field.field.node.link.field_topic2                                                                                                                               
 uuid: f3c818dd-b5cd-4a73-af88-c20c1d0e24c3                                                                                                                       
 langcode: en                                                                                                                                                     
 status: true                                                                                                                                                     
 dependencies:                                                                                                                                                    
   config:                                                                                                                                                        
     - field.storage.node.field_topic2                                                                                                                            
     - node.type.link                                                                                                                                             
     - taxonomy.vocabulary.topic                                                                                                                                  
 id: node.link.field_topic2                                                                                                                                       
 field_name: field_topic2                                                                                                                                         
 entity_type: node                                                                                                                                                
 bundle: link                                                                                                                                                     
 label: Topic                                                                                                                                                     
 description: "Sätt flera olika ämnen, separera dem med kommatecken och inled med stor bokstav.\r\n<br>\r\nExempel: SEB, Fraktionella reserver, Svågerkapitalism" 
 required: true                                                                                                                                                   
 translatable: false                                                                                                                                              
 default_value: {  }                                                                                                                                              
 default_value_callback: ''                                                                                                                                       
 settings:                                                                                                                                                        
   handler: 'default:taxonomy_term'                                                                                                                               
   handler_settings:                                                                                                                                              
     target_bundles:                                                                                                                                              
       topic: topic                                                                                                                                               
     sort:                                                                                                                                                        
       field: name                                                                                                                                                
       direction: asc                                                                                                                                             
     auto_create: true                                                                                                                                            
     auto_create_bundle: ''                                                                                                                                       
 field_type: entity_reference

Answer 1

There are multiple ways to achieve this, but I think the most clean is: Config Override.

I suggest to read the whole to understand it, but only this part is needed for you: Providing overrides from modules

You need then only find the configuration you want to override in runtime, and do it based on the current user role.

The field config pattern you are looking for is the following: field.field.entity_type.bundle.field_name

The auto_create is under 'settings/handler_settings'.

HOW TO FIND AND EXAMINE THE CONFIGS YOU NEED

Configs are also entities. They can be feetched with EntityTypeManager. To see what type of entities you have in the system you have the "getDefinitions()" method. Then all you have to do, is to find the right storage (getStorage($config_entity_type)), and then load it by ID. Printing it out with kint, will give you a nice overview how the entity looks like, and how the settings are stored.

You can also "drush cex" your configuration. In this case configuration files will be created. The same scheme can be also found here. It gives also a good overview.

Answer 2

I am able to solve it by 2 methods :

First : http://www.drupalcontrib.org/api/drupal/drupal%21core%21modules%21field%21field.api.php/function/hook_field_widget_WIDGET_TYPE_form_alter/8

function my_module_field_widget_form_alter(&$element, &$form_state, $context) {


if ($element['target_id']['#type'] == 'entity_autocomplete' && $element['target_id']['#target_type'] == 'taxonomy_term' && !empty($element['target_id']['#selection_settings']['target_bundles']['topic'])) {

$current_user = \Drupal::currentUser();
$roles = $current_user->getRoles();

    if(!in_array(ROLE_ADMIN, $roles)){
      if (!in_array('my_role', $roles) || in_array('anonymous', $roles)) {
        unset($element['target_id']['#autocreate']);
      }
    }
  }
}

Second

By creating my own widget simialr to Autocomplete tag style and overriding formElement in that to remove auto_create fields support based on user role.

Third:

As suggested by @ssibal [Config Override.][1] (but problem in this )

$current_user = \Drupal::currentUser();
    $roles = $current_user->getRoles();

    if (!in_array('my_role', $roles)) {
        $overrides = $overrides + [
            'field.field.node.link.field_topic2' => [
              'settings' => ['handler_settings' => ['auto_create' => 0 ]],
            ],
          ];
     }


        return $overrides;