journal/modules/custom/journal_peer_review/journal_peer_review.module

<?php

use Drupal\Core\Access\AccessResult;
use Drupal\node\NodeInterface;
use Drupal\Core\Entity\Entity\EntityFormDisplay;
use Drupal\Core\Entity\Entity\EntityViewDisplay;
use Drupal\Core\Session\AccountInterface;
use Drupal\journal_peer_review\Utils;

/**
 * Implementation of hook_modules_installed().
 *
 * Workaround because custom field permissions are not exporting properly.
 * Limit who can view the 'assigned reviewer' field to only Journal and Issue reviewwers.
 *
 * @param array $modules
 */
function journal_peer_review_modules_installed(array $modules) {
  journal_peer_review_grant_field_permissions(
    [
      'create field_peer_reviewer' => [
        'journal_editor',
        'issue_editor',
      ],
      'edit field_peer_reviewer' => [
        'journal_editor',
        'issue_editor',
      ],
      'view field_peer_reviewer' => [
        'journal_editor',
        'issue_editor',
      ],
    ]);

  $field = \Drupal\field\Entity\FieldConfig::loadByName('node', 'journal_article', 'field_authors_and_affiliations');
  $storage = $field->getFieldStorageDefinition();
  $storage->setThirdPartySetting('field_permissions', 'permission_type', 'custom');
  $storage->save();

  foreach ([
             'field_authors_and_affiliations',
             'field_affiliation_contributor',
             'field_affiliation_string'
           ] as $field_name) {
    journal_peer_review_grant_field_permissions(
      [
        "create $field_name" => [
          'journal_editor',
          'issue_editor',
          'journal_article_creator',
        ],
        "edit own $field_name" => [
          'journal_editor',
          'issue_editor',
          'journal_article_creator',
        ],
        "edit $field_name" => [
          'issue_editor',
          'journal_editor',
        ],
        "view own $field_name" => [
          'journal_article_creator',
        ],
        "view $field_name" => [
          'issue_editor',
          'journal_editor',
        ],
      ]
    );
  }


  // Put Assigned Reviewer into the Publication State form region.
  $form_entity = EntityFormDisplay::load('node.journal_article.default');
  $group_data = $form_entity->getThirdPartySettings('field_group');
  $pubstate_group = $group_data['group_publication_state'];
  array_splice($pubstate_group['children'], 1, 0, 'field_peer_reviewer');
  $form_entity->setComponent('field_peer_reviewer', ['region' => 'content'])
  ->setThirdPartySetting('field_group', 'group_publication_state', $pubstate_group)
  ->save();

  // Add 'Peer Reviewers' field to the Entity View Display
  $view_entity = EntityViewDisplay::load('node.journal_article.default');
  $view_entity->setComponent('field_peer_reviewer', [
    'type' => 'entity_reference_label',
    'weight' => 5,
    'region' => 'content',
    'label' => 'above',
    'settings' => ['link' => '1']])
    ->save();
}


/**
 * Implements hook_node_access().
 *
 * @inheritdoc
 */
function journal_peer_review_node_access(NodeInterface $node, $op, AccountInterface $account) {

  if ($node->bundle() != 'journal_article') {
    return AccessResult::neutral();
  }

  // Pass-through if node is published as we are through the peer review process.
  if ($node->isPublished()) {
    return AccessResult::neutral();
  }

  // If user does not have article reviewer role, just pass through
  // and let the standard Drupal access rules handle it.
  if (!in_array('journal_article_reviewer', $account->getRoles())) {
    return AccessResult::neutral();
  }

  $reviewers = $node->get('field_peer_reviewer');

  if (!empty($reviewers) && is_a($reviewers, 'Drupal\Core\Field\EntityReferenceFieldItemList')) {
    foreach ($reviewers->referencedEntities() as $reviewer) {
      if ($reviewer->getEntityTypeId() == 'user' && $reviewer->id() == $account->id()) {
        // User is in the assigned reviewers list, so they can see the article.
        return AccessResult::allowed();
      }
    }
  }

  return AccessResult::forbidden();
}

/**
 * Loop through the array and grant permissions for the specified roels on each field.
 *
 * @param $permissions
 */
function journal_peer_review_grant_field_permissions($permissions) {
  $role_storage = \Drupal::service('entity_type.manager')->getStorage('user_role');
  $roles = [];

  foreach ($permissions as $permission_name => $role_names) {
    foreach ($role_names as $role_name) {
      $roles[$role_name] = $role_storage->load($role_name);
      if (!empty($roles[$role_name])) {
        $roles[$role_name]->grantPermission($permission_name);
      }
    }
  }

  // Save all roles.
//  foreach ($roles as $role) {
//    $role->trustData()->save();
//  }
}