first commit

modules/devel/devel_generate/README.md

@@ -0,0 +1,59 @@
+[[_TOC_]]
+
+This module may be used to create entities that contain sample content. This is
+useful when showing off your site to a client, for example. Even if the content
+is not yet available, the site can show its look and feel and behavior.
+
+The sample entities may be created via the Web or via the included Drush commands
+like `drush genc`.
+
+#### Recommended Modules
+
+- [Devel Images Provider](http://drupal.org/project/devel_image_provider) allows to configure external providers for images.
+
+#### Custom plugins
+
+This module creates the _DevelGenerate_ plugin type.
+
+All you need to do to provide a new instance for DevelGenerate plugin type
+is to create your class extending `DevelGenerateBase` and following these steps:
+
+1. Declare your plugin with annotations:
+    ````
+    /**
+     * Provides a ExampleDevelGenerate plugin.
+     *
+     * @DevelGenerate(
+     *   id = "example",
+     *   label = @Translation("example"),
+     *   description = @Translation("Generate a given number of example elements."),
+     *   url = "example",
+     *   permission = "administer example",
+     *   settings = {
+     *     "num" = 50,
+     *     "kill" = FALSE,
+     *     "another_property" = "default_value"
+     *   }
+     * )
+     */
+    ````
+1. Implement the `settingsForm` method to create a form using the properties
+from the annotations.
+1. Implement the `handleDrushParams` method. It should return an array of
+values.
+1. Implement the `generateElements` method. You can write here your business
+logic using the array of values.
+
+#### Notes
+
+- You can alter existing properties for every plugin by implementing
+`hook_devel_generate_info_alter`.
+- DevelGenerateBaseInterface details base wrapping methods that most
+DevelGenerate implementations will want to directly inherit from
+`Drupal\devel_generate\DevelGenerateBase`.
+- To give support for a new field type the field type base class should properly
+implement `\Drupal\Core\Field\FieldItemInterface::generateSampleValue()`.
+Devel Generate automatically uses the values returned by this method during the
+generate process for generating placeholder field values. For more information
+see: https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Field!FieldItemInterface.php/function/FieldItemInterface::generateSampleValue
+- For Drupal 10, the webprofiler module has broken out to its own project at https://www.drupal.org/project/webprofiler

modules/devel/devel_generate/composer.json

@@ -0,0 +1,45 @@
+{
+  "name": "drupal/devel_generate",
+  "description": "Generate test users, nodes, menus, taxonomy terms...",
+  "type": "drupal-module",
+  "homepage": "http://drupal.org/project/devel",
+  "authors": [
+    {
+      "name": "Moshe Weitzman",
+      "email": "weitzman@tejasa.com",
+      "homepage": "https://github.com/weitzman",
+      "role": "Maintainer"
+    },
+    {
+      "name": "Hans Salvisberg",
+      "email": "drupal@salvisberg.com",
+      "homepage": "https://www.drupal.org/u/salvis",
+      "role": "Maintainer"
+    },
+    {
+      "name": "Luca Lusso",
+      "homepage": "https://www.drupal.org/u/lussoluca",
+      "role": "Maintainer"
+    },
+    {
+      "name": "Marco (willzyx)",
+      "homepage": "https://www.drupal.org/u/willzyx",
+      "role": "Maintainer"
+    },
+    {
+      "name": "See contributors",
+      "homepage": "https://www.drupal.org/node/3236/committers"
+    }
+  ],
+  "support": {
+    "issues": "http://drupal.org/project/devel",
+    "irc": "irc://irc.freenode.org/drupal-contribute",
+    "source": "http://cgit.drupalcode.org/devel"
+  },
+  "license": "GPL-2.0-or-later",
+  "minimum-stability": "dev",
+  "require": {},
+  "suggest": {
+    "drupal/realistic_dummy_content": "Generate realistic demo content with Devel's devel_generate module."
+  }
+}

modules/devel/devel_generate/devel_generate.batch.inc

@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * @file
+ * Provides common batch functions for every DevelGeneratePlugin.
+ */
+
+use Drupal\devel_generate\DevelGenerateBaseInterface;
+
+/**
+ * Calls the correct method responsible for handling a given batch operation.
+ */
+function devel_generate_operation(DevelGenerateBaseInterface $class, $method, $vars, &$context) {
+  return $class->$method($vars, $context);
+}
+
+/**
+ * Standard finish batch function.
+ */
+function devel_generate_batch_finished($success, $results, $operations) {
+
+  if ($success) {
+    if (!empty($results['num_translations'])) {
+      $message = t('Finished @num elements and @num_translations translations created successfully.', ['@num' => $results['num'], '@num_translations' => $results['num_translations']]);
+    }
+    else {
+      $message = t('Finished @num elements created successfully.', ['@num' => $results['num']]);
+    }
+  }
+  else {
+    $message = t('Finished with an error.');
+  }
+  \Drupal::messenger()->addMessage($message);
+}

modules/devel/devel_generate/devel_generate.info.yml

@@ -0,0 +1,12 @@
+type: module
+name: 'Devel Generate'
+description: 'Generate test users, nodes, menus, taxonomy terms...'
+package: Development
+core_version_requirement: ">=10.0 <12.0.0-stable"
+tags:
+  - developer
+
+# Information added by Drupal.org packaging script on 2024-06-26
+version: '5.2.1+50-dev'
+project: 'devel'
+datestamp: 1719414589

modules/devel/devel_generate/devel_generate.module

@@ -0,0 +1,57 @@
+<?php
+
+/**
+ * @file
+ * Devel sub-module to for generating content, menus, taxonomy terms etc.
+ *
+ * See src/Plugin for specific details of each type that can be generated.
+ */
+
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * Implements hook_menu_links_discovered_alter().
+ */
+function devel_generate_menu_links_discovered_alter(array &$links): void {
+  $devel_generate_plugins = \Drupal::service('plugin.manager.develgenerate')->getDefinitions();
+  foreach ($devel_generate_plugins as $id => $plugin) {
+    $label = $plugin['label'];
+    $links['devel_generate.' . $id] = [
+      'title' => new TranslatableMarkup("Generate @label", ['@label' => $label]),
+      'parent' => 'devel_generate.admin_config_generate',
+      'description' => $plugin['description'],
+      'route_name' => 'devel_generate.' . $id,
+      'provider' => 'devel_generate',
+    ];
+  }
+
+  // Store the basic link info for repeated use. Each of the three actual links
+  // require subtle variations on this.
+  $basics = [
+    'title' => new TranslatableMarkup('Generate'),
+    'description' => new TranslatableMarkup('Generate realistic items (content, users, menus, etc) to assist your site development and testing.'),
+    'route_name' => 'devel_generate.admin_config_generate',
+    'provider' => 'devel_generate',
+  ];
+
+  // Define a separate group on admin/config page, so that 'Generate' has its
+  // own block with all the generate links.
+  $links['devel_generate.admin_config_generate'] = [
+    'parent' => 'system.admin_config',
+    // The main development group has weight -10 in system.links.menu.yml so use
+    // -9 here as this block should be near but just after it on the page.
+    'weight' => -9,
+  ] + $basics;
+
+  // Add a link in the main development group, to allow direct access to the
+  // the Generate page and to make the back breadcrumb more useful.
+  $links['devel_generate.generate'] = [
+    'title' => new TranslatableMarkup('Devel generate'),
+    'parent' => 'system.admin_config_development',
+  ] + $basics;
+
+  // Define a top-level link (with no parent) in the 'devel' menu. This also
+  // means that it will be available in the devel admin toolbar.
+  $links['devel_generate.generate2'] = ['menu_name' => 'devel'] + $basics;
+
+}

modules/devel/devel_generate/devel_generate.permissions.yml

@@ -0,0 +1,5 @@
+administer devel_generate:
+  title: 'Administer devel_generate'
+
+permission_callbacks:
+  - \Drupal\devel_generate\DevelGeneratePermissions::permissions

modules/devel/devel_generate/devel_generate.routing.yml

@@ -0,0 +1,2 @@
+route_callbacks:
+  - '\Drupal\devel_generate\Routing\DevelGenerateRoutes::routes'

modules/devel/devel_generate/devel_generate.services.yml

@@ -0,0 +1,10 @@
+services:
+  plugin.manager.develgenerate:
+    class: Drupal\devel_generate\DevelGeneratePluginManager
+    parent: default_plugin_manager
+    arguments: ['@entity_type.manager', '@messenger', '@language_manager', '@string_translation', '@entity_field.manager']
+  Drupal\devel_generate\DevelGeneratePluginManager: '@plugin.manager.develgenerate'
+
+  logger.channel.devel_generate:
+    parent: logger.channel_base
+    arguments: ['devel_generate']

modules/devel/devel_generate/src/Annotation/DevelGenerate.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace Drupal\devel_generate\Annotation;
+
+use Drupal\Component\Annotation\Plugin;
+use Drupal\Core\Annotation\Translation;
+
+/**
+ * Defines a DevelGenerate annotation object.
+ *
+ * DevelGenerate handle the bulk creation of entites.
+ *
+ * Additional annotation keys for DevelGenerate can be defined in
+ * hook_devel_generate_info_alter().
+ *
+ * @Annotation
+ *
+ * @see \Drupal\devel_generate\DevelGeneratePluginManager
+ * @see \Drupal\devel_generate\DevelGenerateBaseInterface
+ */
+class DevelGenerate extends Plugin {
+  /**
+   * The human-readable name of the DevelGenerate type.
+   *
+   * @ingroup plugin_translatable
+   */
+  public Translation $label;
+
+  /**
+   * A short description of the DevelGenerate type.
+   *
+   * @ingroup plugin_translatable
+   */
+  public Translation $description;
+
+  /**
+   * A url to access the plugin settings form.
+   */
+  public string $url;
+
+  /**
+   * The permission required to access the plugin settings form.
+   */
+  public string $permission;
+
+  /**
+   * The name of the DevelGenerate class.
+   *
+   * This is not provided manually, it will be added by the discovery mechanism.
+   */
+  public string $class;
+
+  /**
+   * An array of settings passed to the DevelGenerate settingsForm.
+   *
+   * The keys are the names of the settings and the values are the default
+   * values for those settings.
+   */
+  public array $settings = [];
+
+  /**
+   * Modules that should be enabled in order to make the plugin discoverable.
+   */
+  public array $dependencies = [];
+
+}

modules/devel/devel_generate/src/Attributes/Generator.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\devel_generate\Attributes;
+
+use Consolidation\AnnotatedCommand\Parser\CommandInfo;
+
+/**
+ * Devel generate plugin details.
+ */
+#[\Attribute(\Attribute::TARGET_METHOD)]
+class Generator {
+
+  public function __construct(
+    public string $id,
+  ) {}
+
+  public static function handle(\ReflectionAttribute $attribute, CommandInfo $commandInfo): void {
+    $args = $attribute->getArguments();
+    $commandInfo->addAnnotation('pluginId', $args['id']);
+  }
+
+}

modules/devel/devel_generate/src/DevelGenerateBase.php

@@ -0,0 +1,347 @@
+<?php
+
+namespace Drupal\devel_generate;
+
+use Drupal\Component\Utility\Random;
+use Drupal\Core\Entity\EntityFieldManagerInterface;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Entity\FieldableEntityInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\Plugin\PluginBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a base DevelGenerate plugin implementation.
+ */
+abstract class DevelGenerateBase extends PluginBase implements DevelGenerateBaseInterface {
+
+  /**
+   * The entity type manager service.
+   */
+  protected EntityTypeManagerInterface $entityTypeManager;
+
+  /**
+   * The language manager.
+   */
+  protected LanguageManagerInterface $languageManager;
+
+  /**
+   * The module handler.
+   */
+  protected ModuleHandlerInterface $moduleHandler;
+
+  /**
+   * The entity field manager.
+   */
+  protected EntityFieldManagerInterface $entityFieldManager;
+
+  /**
+   * The plugin settings.
+   */
+  protected array $settings = [];
+
+  /**
+   * The random data generator.
+   */
+  protected ?Random $random = NULL;
+
+  /**
+   * Instantiates a new instance of this class.
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $instance = new static($configuration, $plugin_id, $plugin_definition);
+    $instance->entityTypeManager = $container->get('entity_type.manager');
+    $instance->messenger = $container->get('messenger');
+    $instance->languageManager = $container->get('language_manager');
+    $instance->moduleHandler = $container->get('module_handler');
+    $instance->stringTranslation = $container->get('string_translation');
+    $instance->entityFieldManager = $container->get('entity_field.manager');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getSetting(string $key) {
+    // Merge defaults if we have no value for the key.
+    if (!array_key_exists($key, $this->settings)) {
+      $this->settings = $this->getDefaultSettings();
+    }
+
+    return $this->settings[$key] ?? NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefaultSettings(): array {
+    $definition = $this->getPluginDefinition();
+    return $definition['settings'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getSettings(): array {
+    return $this->settings;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsFormValidate(array $form, FormStateInterface $form_state): void {
+    // Validation is optional.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function generate(array $values): void {
+    $this->generateElements($values);
+    $this->setMessage('Generate process complete.');
+  }
+
+  /**
+   * Business logic relating with each DevelGenerate plugin.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   */
+  protected function generateElements(array $values): void {
+
+  }
+
+  /**
+   * Populate the fields on a given entity with sample values.
+   *
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity to be enriched with sample field values.
+   * @param array $skip
+   *   A list of field names to avoid when populating.
+   * @param array $base
+   *   A list of base field names to populate.
+   */
+  public function populateFields(EntityInterface $entity, array $skip = [], array $base = []): void {
+    if (!$entity->getEntityType()->entityClassImplements(FieldableEntityInterface::class)) {
+      // Nothing to do.
+      return;
+    }
+
+    $instances = $this->entityFieldManager->getFieldDefinitions($entity->getEntityTypeId(), $entity->bundle());
+    $instances = array_diff_key($instances, array_flip($skip));
+    foreach ($instances as $instance) {
+      $field_storage = $instance->getFieldStorageDefinition();
+      $field_name = $field_storage->getName();
+      if ($field_storage->isBaseField() && !in_array($field_name, $base)) {
+        // Skip base field unless specifically requested.
+        continue;
+      }
+
+      $max = $field_storage->getCardinality();
+      $cardinality = $max;
+      if ($cardinality == FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED) {
+        // Just an arbitrary number for 'unlimited'.
+        $max = random_int(1, 3);
+      }
+
+      $entity->$field_name->generateSampleItems($max);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function handleDrushParams($args) {
+
+  }
+
+  /**
+   * Set a message for either drush or the web interface.
+   *
+   * @param string|\Drupal\Component\Render\MarkupInterface $msg
+   *   The message to display.
+   * @param string $type
+   *   (optional) The message type, as defined in MessengerInterface. Defaults
+   *   to MessengerInterface::TYPE_STATUS.
+   */
+  protected function setMessage($msg, string $type = MessengerInterface::TYPE_STATUS): void {
+    if (function_exists('drush_log')) {
+      $msg = strip_tags($msg);
+      drush_log($msg);
+    }
+    else {
+      $this->messenger->addMessage($msg, $type);
+    }
+  }
+
+  /**
+   * Check if a given param is a number.
+   *
+   * @param mixed $number
+   *   The parameter to check.
+   *
+   * @return bool
+   *   TRUE if the parameter is a number, FALSE otherwise.
+   */
+  public static function isNumber(mixed $number): bool {
+    if ($number === NULL) {
+      return FALSE;
+    }
+
+    return is_numeric($number);
+  }
+
+  /**
+   * Returns the random data generator.
+   *
+   * @return \Drupal\Component\Utility\Random
+   *   The random data generator.
+   */
+  protected function getRandom(): Random {
+    if (!$this->random instanceof Random) {
+      $this->random = new Random();
+    }
+
+    return $this->random;
+  }
+
+  /**
+   * Generates a random sentence of specific length.
+   *
+   * Words are randomly selected with length from 2 up to the optional parameter
+   * $max_word_length. The first word is capitalised. No ending period is added.
+   *
+   * @param int $sentence_length
+   *   The total length of the sentence, including the word-separating spaces.
+   * @param int $max_word_length
+   *   (optional) Maximum length of each word. Defaults to 8.
+   *
+   * @return string
+   *   A sentence of the required length.
+   */
+  protected function randomSentenceOfLength(int $sentence_length, int $max_word_length = 8): string {
+    // Maximum word length cannot be longer than the sentence length.
+    $max_word_length = min($sentence_length, $max_word_length);
+    $words = [];
+    $remainder = $sentence_length;
+    do {
+      // If near enough to the end then generate the exact length word to fit.
+      // Otherwise, the remaining space cannot be filled with one word, so
+      // choose a random length, short enough for a following word of at least
+      // minimum length.
+      $next_word = $remainder <= $max_word_length ? $remainder : mt_rand(2, min($max_word_length, $remainder - 3));
+
+      $words[] = $this->getRandom()->word($next_word);
+      $remainder = $remainder - $next_word - 1;
+    } while ($remainder > 0);
+
+    return ucfirst(implode(' ', $words));
+  }
+
+  /**
+   * Creates the language and translation section of the form.
+   *
+   * This is used by both Content and Term generation.
+   *
+   * @param string $items
+   *   The name of the things that are being generated - 'nodes' or 'terms'.
+   *
+   * @return array
+   *   The language details section of the form.
+   */
+  protected function getLanguageForm(string $items): array {
+    // We always need a language, even if the language module is not installed.
+    $options = [];
+    $languages = $this->languageManager->getLanguages(LanguageInterface::STATE_CONFIGURABLE);
+    foreach ($languages as $langcode => $language) {
+      $options[$langcode] = $language->getName();
+    }
+
+    $language_module_exists = $this->moduleHandler->moduleExists('language');
+    $translation_module_exists = $this->moduleHandler->moduleExists('content_translation');
+
+    $form['language'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Language'),
+      '#open' => $language_module_exists,
+    ];
+    $form['language']['add_language'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Select the primary language(s) for @items', ['@items' => $items]),
+      '#multiple' => TRUE,
+      '#description' => $language_module_exists ? '' : $this->t('Disabled - requires Language module'),
+      '#options' => $options,
+      '#default_value' => [
+        $this->languageManager->getDefaultLanguage()->getId(),
+      ],
+      '#disabled' => !$language_module_exists,
+    ];
+    $form['language']['translate_language'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Select the language(s) for translated @items', ['@items' => $items]),
+      '#multiple' => TRUE,
+      '#description' => $translation_module_exists ? $this->t('Translated @items will be created for each language selected.', ['@items' => $items]) : $this->t('Disabled - requires Content Translation module.'),
+      '#options' => $options,
+      '#disabled' => !$translation_module_exists,
+    ];
+    return $form;
+  }
+
+  /**
+   * Return a language code.
+   *
+   * @param array $add_language
+   *   Optional array of language codes from which to select one at random.
+   *   If empty then return the site's default language.
+   *
+   * @return string
+   *   The language code to use.
+   */
+  protected function getLangcode(array $add_language): string {
+    if ($add_language === []) {
+      return $this->languageManager->getDefaultLanguage()->getId();
+    }
+
+    return $add_language[array_rand($add_language)];
+  }
+
+  /**
+   * Convert a csv string into an array of items.
+   *
+   * Borrowed from Drush.
+   *
+   * @param string|array|null $args
+   *   A simple csv string; e.g. 'a,b,c'
+   *   or a simple list of items; e.g. array('a','b','c')
+   *   or some combination; e.g. array('a,b','c') or array('a,','b,','c,').
+   */
+  public static function csvToArray($args): array {
+    if ($args === NULL) {
+      return [];
+    }
+
+    // 1: implode(',',$args) converts from array('a,','b,','c,') to 'a,,b,,c,'
+    // 2: explode(',', ...) converts to array('a','','b','','c','')
+    // 3: array_filter(...) removes the empty items
+    // 4: array_map(...) trims extra whitespace from each item
+    // (handles csv strings with extra whitespace, e.g. 'a, b, c')
+    //
+    $args = is_array($args) ? implode(',', array_map('strval', $args)) : (string) $args;
+    return array_map('trim', array_filter(explode(',', $args)));
+  }
+
+}

modules/devel/devel_generate/src/DevelGenerateBaseInterface.php

@@ -0,0 +1,88 @@
+<?php
+
+namespace Drupal\devel_generate;
+
+use Drupal\Component\Plugin\PluginInspectionInterface;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Base interface definition for "DevelGenerate" plugins.
+ *
+ * This interface details base wrapping methods that most DevelGenerate
+ * implementations will want to directly inherit from
+ * Drupal\devel_generate\DevelGenerateBase.
+ *
+ * DevelGenerate implementation plugins should have their own settingsForm() and
+ * generateElements() to achieve their own behaviour.
+ */
+interface DevelGenerateBaseInterface extends PluginInspectionInterface {
+
+  public function __construct(array $configuration, $plugin_id, $plugin_definition);
+
+  /**
+   * Returns the array of settings, including defaults for missing settings.
+   *
+   * @param string $key
+   *   The setting name.
+   *
+   * @return array|int|string|bool|null
+   *   The setting.
+   */
+  public function getSetting(string $key);
+
+  /**
+   * Returns the default settings for the plugin.
+   *
+   * @return array
+   *   The array of default setting values, keyed by setting names.
+   */
+  public function getDefaultSettings(): array;
+
+  /**
+   * Returns the current settings for the plugin.
+   *
+   * @return array
+   *   The array of current setting values, keyed by setting names.
+   */
+  public function getSettings(): array;
+
+  /**
+   * Returns the form for the plugin.
+   *
+   * @return array
+   *   The array of default setting values, keyed by setting names.
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array;
+
+  /**
+   * Form validation handler.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   */
+  public function settingsFormValidate(array $form, FormStateInterface $form_state): void;
+
+  /**
+   * Execute the instructions in common for all DevelGenerate plugin.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   */
+  public function generate(array $values): void;
+
+  /**
+   * Responsible for validating Drush params.
+   *
+   * @param array $args
+   *   The command arguments.
+   * @param array $options
+   *   The commend options.
+   *
+   * @return array
+   *   An array of values ready to be used for generateElements().
+   */
+  public function validateDrushParams(array $args, array $options = []): array;
+
+}

modules/devel/devel_generate/src/DevelGenerateException.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace Drupal\devel_generate;
+
+/**
+ * DevelGenerateException extending Generic Plugin exception class.
+ */
+class DevelGenerateException extends \Exception {
+
+}

modules/devel/devel_generate/src/DevelGeneratePermissions.php

@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\devel_generate;
+
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides dynamic permissions of the filter module.
+ */
+class DevelGeneratePermissions implements ContainerInjectionInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * The plugin manager.
+   */
+  protected DevelGeneratePluginManager $develGeneratePluginManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container): self {
+    $instance = new self();
+    $instance->develGeneratePluginManager = $container->get('plugin.manager.develgenerate');
+    $instance->stringTranslation = $container->get('string_translation');
+
+    return $instance;
+  }
+
+  /**
+   * A permissions' callback.
+   *
+   * @see devel_generate.permissions.yml
+   *
+   * @return array
+   *   An array of permissions for all plugins.
+   */
+  public function permissions(): array {
+    $permissions = [];
+    $devel_generate_plugins = $this->develGeneratePluginManager->getDefinitions();
+    foreach ($devel_generate_plugins as $plugin) {
+      $permission = $plugin['permission'];
+      $permissions[$permission] = [
+        'title' => $this->t('@permission', ['@permission' => $permission]),
+      ];
+    }
+
+    return $permissions;
+  }
+
+}

modules/devel/devel_generate/src/DevelGeneratePluginManager.php

@@ -0,0 +1,105 @@
+<?php
+
+namespace Drupal\devel_generate;
+
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\Entity\EntityFieldManagerInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\Plugin\DefaultPluginManager;
+use Drupal\Core\StringTranslation\TranslationInterface;
+use Drupal\devel_generate\Annotation\DevelGenerate;
+
+/**
+ * Plugin type manager for DevelGenerate plugins.
+ */
+class DevelGeneratePluginManager extends DefaultPluginManager {
+
+  /**
+   * The entity type manager.
+   */
+  protected EntityTypeManagerInterface $entityTypeManager;
+
+  /**
+   * The messenger service.
+   */
+  protected MessengerInterface $messenger;
+
+  /**
+   * The language manager.
+   */
+  protected LanguageManagerInterface $languageManager;
+
+  /**
+   * The translation manager.
+   */
+  protected TranslationInterface $stringTranslation;
+
+  /**
+   * Constructs a DevelGeneratePluginManager object.
+   *
+   * @param \Traversable $namespaces
+   *   An object that implements \Traversable which contains the root paths
+   *   keyed by the corresponding namespace to look for plugin implementations.
+   * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
+   *   Cache backend instance to use.
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler to invoke the alter hook with.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager.
+   * @param \Drupal\Core\Messenger\MessengerInterface $messenger
+   *   The messenger service.
+   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
+   *   The language manager.
+   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
+   *   The translation manager.
+   * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entityFieldManager
+   *   The entity field manager.
+   */
+  public function __construct(
+    \Traversable $namespaces,
+    CacheBackendInterface $cache_backend,
+    ModuleHandlerInterface $module_handler,
+    EntityTypeManagerInterface $entity_type_manager,
+    MessengerInterface $messenger,
+    LanguageManagerInterface $language_manager,
+    TranslationInterface $string_translation,
+    protected EntityFieldManagerInterface $entityFieldManager,
+  ) {
+    parent::__construct('Plugin/DevelGenerate', $namespaces, $module_handler, NULL, DevelGenerate::class);
+    $this->entityTypeManager = $entity_type_manager;
+    $this->messenger = $messenger;
+    $this->languageManager = $language_manager;
+    $this->moduleHandler = $module_handler;
+    $this->stringTranslation = $string_translation;
+    $this->alterInfo('devel_generate_info');
+    $this->setCacheBackend($cache_backend, 'devel_generate_plugins');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function findDefinitions(): array {
+    $definitions = [];
+    foreach (parent::findDefinitions() as $plugin_id => $plugin_definition) {
+      $plugin_available = TRUE;
+      foreach ($plugin_definition['dependencies'] as $module_name) {
+        // If a plugin defines module dependencies and at least one module is
+        // not installed don't make this plugin available.
+        if (!$this->moduleHandler->moduleExists($module_name)) {
+          $plugin_available = FALSE;
+          break;
+        }
+      }
+
+      if ($plugin_available) {
+        $definitions[$plugin_id] = $plugin_definition;
+      }
+    }
+
+    return $definitions;
+  }
+
+}

modules/devel/devel_generate/src/Drush/Commands/DevelGenerateCommands.php

@@ -0,0 +1,263 @@
+<?php
+
+namespace Drupal\devel_generate\Drush\Commands;
+
+use Consolidation\AnnotatedCommand\CommandData;
+use Consolidation\AnnotatedCommand\Hooks\HookManager;
+use Drupal\devel_generate\Attributes\Generator;
+use Drupal\devel_generate\DevelGenerateBaseInterface;
+use Drupal\devel_generate\DevelGeneratePluginManager;
+use Drush\Attributes as CLI;
+use Drush\Commands\AutowireTrait;
+use Drush\Commands\DrushCommands;
+
+/**
+ * Provide Drush commands for all the core Devel Generate plugins.
+ *
+ * For commands that are parts of modules, Drush expects to find commandfiles in
+ * __MODULE__/src/Drush/Commands, and the namespace is Drupal/__MODULE__/Drush/Commands.
+ */
+final class DevelGenerateCommands extends DrushCommands {
+
+  use AutowireTrait;
+
+  const USERS = 'devel-generate:users';
+
+  const TERMS = 'devel-generate:terms';
+
+  const VOCABS = 'devel-generate:vocabs';
+
+  const MENUS = 'devel-generate:menus';
+
+  const CONTENT = 'devel-generate:content';
+
+  const BLOCK_CONTENT = 'devel-generate:block-content';
+
+  const MEDIA = 'devel-generate:media';
+
+  /**
+   * The plugin instance.
+   */
+  private DevelGenerateBaseInterface $pluginInstance;
+
+  /**
+   * The Generate plugin parameters.
+   */
+  private array $parameters;
+
+  /**
+   * DevelGenerateCommands constructor.
+   *
+   * @param \Drupal\devel_generate\DevelGeneratePluginManager $manager
+   *   The DevelGenerate plugin manager.
+   */
+  public function __construct(protected DevelGeneratePluginManager $manager) {
+    parent::__construct();
+    $this->setManager($manager);
+  }
+
+  /**
+   * Get the DevelGenerate plugin manager.
+   *
+   * @return \Drupal\devel_generate\DevelGeneratePluginManager
+   *   The DevelGenerate plugin manager.
+   */
+  public function getManager(): DevelGeneratePluginManager {
+    return $this->manager;
+  }
+
+  /**
+   * Set the DevelGenerate plugin manager.
+   *
+   * @param \Drupal\devel_generate\DevelGeneratePluginManager $manager
+   *   The DevelGenerate plugin manager.
+   */
+  public function setManager(DevelGeneratePluginManager $manager): void {
+    $this->manager = $manager;
+  }
+
+  /**
+   * Get the DevelGenerate plugin instance.
+   *
+   * @return \Drupal\devel_generate\DevelGenerateBaseInterface
+   *   The DevelGenerate plugin instance.
+   */
+  public function getPluginInstance(): DevelGenerateBaseInterface {
+    return $this->pluginInstance;
+  }
+
+  /**
+   * Set the DevelGenerate plugin instance.
+   *
+   * @param mixed $pluginInstance
+   *   The DevelGenerate plugin instance.
+   */
+  public function setPluginInstance(mixed $pluginInstance): void {
+    $this->pluginInstance = $pluginInstance;
+  }
+
+  /**
+   * Get the DevelGenerate plugin parameters.
+   *
+   * @return array
+   *   The plugin parameters.
+   */
+  public function getParameters(): array {
+    return $this->parameters;
+  }
+
+  /**
+   * Set the DevelGenerate plugin parameters.
+   *
+   * @param array $parameters
+   *   The plugin parameters.
+   */
+  public function setParameters(array $parameters): void {
+    $this->parameters = $parameters;
+  }
+
+  /**
+   * Create users.
+   */
+  #[CLI\Command(name: self::USERS, aliases: ['genu', 'devel-generate-users'])]
+  #[CLI\Argument(name: 'num', description: 'Number of users to generate.')]
+  #[CLI\Option(name: 'kill', description: 'Delete all users before generating new ones.')]
+  #[CLI\Option(name: 'roles', description: 'A comma delimited list of role IDs for new users. Don\'t specify <info>authenticated</info>.')]
+  #[CLI\Option(name: 'pass', description: 'Specify a password to be set for all generated users.')]
+  #[Generator(id: 'user')]
+  public function users(int $num = 50, array $options = ['kill' => FALSE, 'roles' => self::REQ]): void {
+    // @todo pass $options to the plugins.
+    $this->generate();
+  }
+
+  /**
+   * Create terms in specified vocabulary.
+   */
+  #[CLI\Command(name: self::TERMS, aliases: ['gent', 'devel-generate-terms'])]
+  #[CLI\Argument(name: 'num', description: 'Number of terms to generate.')]
+  #[CLI\Option(name: 'kill', description: 'Delete all terms in these vocabularies before generating new ones.')]
+  #[CLI\Option(name: 'bundles', description: 'A comma-delimited list of machine names for the vocabularies where terms will be created.')]
+  #[CLI\Option(name: 'feedback', description: 'An integer representing interval for insertion rate logging.')]
+  #[CLI\Option(name: 'languages', description: 'A comma-separated list of language codes')]
+  #[CLI\Option(name: 'translations', description: 'A comma-separated list of language codes for translations.')]
+  #[CLI\Option(name: 'min-depth', description: 'The minimum depth of hierarchy for the new terms.')]
+  #[CLI\Option(name: 'max-depth', description: 'The maximum depth of hierarchy for the new terms.')]
+  #[Generator(id: 'term')]
+  public function terms(int $num = 50, array $options = ['kill' => FALSE, 'bundles' => self::REQ, 'feedback' => '1000', 'languages' => self::REQ, 'translations' => self::REQ, 'min-depth' => '1', 'max-depth' => '4']): void {
+    $this->generate();
+  }
+
+  /**
+   * Create vocabularies.
+   */
+  #[CLI\Command(name: self::VOCABS, aliases: ['genv', 'devel-generate-vocabs'])]
+  #[CLI\Argument(name: 'num', description: 'Number of vocabularies to generate.')]
+  #[Generator(id: 'vocabulary')]
+  #[CLI\ValidateModulesEnabled(modules: ['taxonomy'])]
+  #[CLI\Option(name: 'kill', description: 'Delete all vocabs before generating new ones.')]
+  public function vocabs(int $num = 1, array $options = ['kill' => FALSE]): void {
+    $this->generate();
+  }
+
+  /**
+   * Create menus.
+   */
+  #[CLI\Command(name: self::MENUS, aliases: ['genm', 'devel-generate-menus'])]
+  #[CLI\Argument(name: 'number_menus', description: 'Number of menus to generate.')]
+  #[CLI\Argument(name: 'number_links', description: 'Number of links to generate.')]
+  #[CLI\Argument(name: 'max_depth', description: 'Max link depth.')]
+  #[CLI\Argument(name: 'max_width', description: 'Max width of first level of links.')]
+  #[CLI\Option(name: 'kill', description: 'Delete any menus and menu links previously created by devel_generate before generating new ones.')]
+  #[Generator(id: 'menu')]
+  public function menus(int $number_menus = 2, int $number_links = 50, int $max_depth = 3, int $max_width = 8, array $options = ['kill' => FALSE]): void {
+    $this->generate();
+  }
+
+  /**
+   * Create content.
+   */
+  #[CLI\Command(name: self::CONTENT, aliases: ['genc', 'devel-generate-content'])]
+  #[CLI\ValidateModulesEnabled(modules: ['node'])]
+  #[CLI\Argument(name: 'num', description: 'Number of nodes to generate.')]
+  #[CLI\Argument(name: 'max_comments', description: 'Maximum number of comments to generate.')]
+  #[CLI\Option(name: 'kill', description: 'Delete all content before generating new content.')]
+  #[CLI\Option(name: 'bundles', description: 'A comma-delimited list of content types to create.')]
+  #[CLI\Option(name: 'authors', description: 'A comma delimited list of authors ids. Defaults to all users.')]
+  #[CLI\Option(name: 'roles', description: 'A comma delimited list of role machine names to filter the random selection of users. Defaults to all roles.')]
+  #[CLI\Option(name: 'feedback', description: 'An integer representing interval for insertion rate logging.')]
+  #[CLI\Option(name: 'skip-fields', description: 'A comma delimited list of fields to omit when generating random values')]
+  #[CLI\Option(name: 'base-fields', description: 'A comma delimited list of base field names to populate')]
+  #[CLI\Option(name: 'languages', description: 'A comma-separated list of language codes')]
+  #[CLI\Option(name: 'translations', description: 'A comma-separated list of language codes for translations.')]
+  #[CLI\Option(name: 'add-type-label', description: 'Add the content type label to the front of the node title')]
+  #[Generator(id: 'content')]
+  public function content(int $num = 50, int $max_comments = 0, array $options = ['kill' => FALSE, 'bundles' => 'page,article', 'authors' => self::REQ, 'roles' => self::REQ, 'feedback' => 1000, 'skip-fields' => self::REQ, 'base-fields' => self::REQ, 'languages' => self::REQ, 'translations' => self::REQ, 'add-type-label' => FALSE]): void {
+    $this->generate();
+  }
+
+  /**
+   * Create Block content blocks.
+   */
+  #[CLI\Command(name: self::BLOCK_CONTENT, aliases: ['genbc', 'devel-generate-block-content'])]
+  #[CLI\ValidateModulesEnabled(modules: ['block_content'])]
+  #[CLI\Argument(name: 'num', description: 'Number of blocks to generate.')]
+  #[CLI\Option(name: 'kill', description: 'Delete all block content before generating new.')]
+  #[CLI\Option(name: 'block_types', description: 'A comma-delimited list of block content types to create.')]
+  #[CLI\Option(name: 'authors', description: 'A comma delimited list of authors ids. Defaults to all users.')]
+  #[CLI\Option(name: 'feedback', description: 'An integer representing interval for insertion rate logging.')]
+  #[CLI\Option(name: 'skip-fields', description: 'A comma delimited list of fields to omit when generating random values')]
+  #[CLI\Option(name: 'base-fields', description: 'A comma delimited list of base field names to populate')]
+  #[CLI\Option(name: 'languages', description: 'A comma-separated list of language codes')]
+  #[CLI\Option(name: 'translations', description: 'A comma-separated list of language codes for translations.')]
+  #[CLI\Option(name: 'add-type-label', description: 'Add the block type label to the front of the node title')]
+  #[CLI\Option(name: 'reusable', description: 'Create re-usable blocks. Disable for inline Layout Builder blocks, for example.')]
+  #[Generator(id: 'block_content')]
+  public function blockContent(int $num = 50, array $options = ['kill' => FALSE, 'block_types' => 'basic', 'feedback' => 1000, 'skip-fields' => self::REQ, 'base-fields' => self::REQ, 'languages' => self::REQ, 'translations' => self::REQ, 'add-type-label' => FALSE, 'reusable' => TRUE]): void {
+    $this->generate();
+  }
+
+  /**
+   * Create media items.
+   */
+  #[CLI\Command(name: self::MEDIA, aliases: ['genmd', 'devel-generate-media'])]
+  #[CLI\Argument(name: 'num', description: 'Number of media to generate.')]
+  #[CLI\Option(name: 'kill', description: 'Delete all media items before generating new.')]
+  #[CLI\Option(name: 'media_types', description: 'A comma-delimited list of media types to create.')]
+  #[CLI\Option(name: 'feedback', description: 'An integer representing interval for insertion rate logging.')]
+  #[CLI\Option(name: 'skip-fields', description: 'A comma delimited list of fields to omit when generating random values')]
+  #[CLI\Option(name: 'base-fields', description: 'A comma delimited list of base field names to populate')]
+  #[CLI\Option(name: 'languages', description: 'A comma-separated list of language codes')]
+  #[CLI\ValidateModulesEnabled(modules: ['media'])]
+  #[Generator(id: 'media')]
+  public function media(int $num = 50, array $options = ['kill' => FALSE, 'media-types' => self::REQ, 'feedback' => 1000, 'skip-fields' => self::REQ, 'languages' => self::REQ, 'base-fields' => self::REQ]): void {
+    $this->generate();
+  }
+
+  /**
+   * The standard drush validate hook.
+   *
+   * @param \Consolidation\AnnotatedCommand\CommandData $commandData
+   *   The data sent from the drush command.
+   */
+  #[CLI\Hook(HookManager::ARGUMENT_VALIDATOR)]
+  public function validate(CommandData $commandData): void {
+    $manager = $this->manager;
+    $args = $commandData->input()->getArguments();
+    // The command name is the first argument but we do not need this.
+    array_shift($args);
+    /** @var \Drupal\devel_generate\DevelGenerateBaseInterface $instance */
+    $instance = $manager->createInstance($commandData->annotationData()->get('pluginId'), []);
+    $this->setPluginInstance($instance);
+    $parameters = $instance->validateDrushParams($args, $commandData->input()->getOptions());
+    $this->setParameters($parameters);
+  }
+
+  /**
+   * Wrapper for calling the plugin instance generate function.
+   */
+  public function generate(): void {
+    $instance = $this->pluginInstance;
+    $instance->generate($this->parameters);
+  }
+
+}

modules/devel/devel_generate/src/Form/DevelGenerateForm.php

@@ -0,0 +1,112 @@
+<?php
+
+namespace Drupal\devel_generate\Form;
+
+use Drupal\Component\Plugin\PluginManagerInterface;
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\devel_generate\DevelGenerateBaseInterface;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Defines a form that allows privileged users to generate entities.
+ */
+class DevelGenerateForm extends FormBase {
+
+  /**
+   * The manager to be used for instantiating plugins.
+   */
+  protected PluginManagerInterface $develGenerateManager;
+
+  /**
+   * Logger service.
+   */
+  protected LoggerInterface $logger;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container): static {
+    $instance = parent::create($container);
+    $instance->develGenerateManager = $container->get('plugin.manager.develgenerate');
+    $instance->messenger = $container->get('messenger');
+    $instance->logger = $container->get('logger.channel.devel_generate');
+    $instance->requestStack = $container->get('request_stack');
+    $instance->stringTranslation = $container->get('string_translation');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId(): string {
+    return 'devel_generate_form_' . $this->getPluginIdFromRequest();
+  }
+
+  /**
+   * Returns the value of the param _plugin_id for the current request.
+   *
+   * @see \Drupal\devel_generate\Routing\DevelGenerateRouteSubscriber
+   */
+  protected function getPluginIdFromRequest() {
+    $request = $this->requestStack->getCurrentRequest();
+    return $request->get('_plugin_id');
+  }
+
+  /**
+   * Returns a DevelGenerate plugin instance for a given plugin id.
+   *
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   *
+   * @return \Drupal\devel_generate\DevelGenerateBaseInterface
+   *   A DevelGenerate plugin instance.
+   */
+  public function getPluginInstance(string $plugin_id): DevelGenerateBaseInterface {
+    return $this->develGenerateManager->createInstance($plugin_id, []);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state): array {
+    $plugin_id = $this->getPluginIdFromRequest();
+    $instance = $this->getPluginInstance($plugin_id);
+    $form = $instance->settingsForm($form, $form_state);
+    $form['actions'] = ['#type' => 'actions'];
+    $form['actions']['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Generate'),
+      '#button_type' => 'primary',
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state): void {
+    $plugin_id = $this->getPluginIdFromRequest();
+    $instance = $this->getPluginInstance($plugin_id);
+    $instance->settingsFormValidate($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state): void {
+    try {
+      $plugin_id = $this->getPluginIdFromRequest();
+      $instance = $this->getPluginInstance($plugin_id);
+      $instance->generate($form_state->getValues());
+    }
+    catch (\Exception $e) {
+      $this->logger->error($this->t('Failed to generate elements due to "%error".', ['%error' => $e->getMessage()]));
+      $this->messenger->addMessage($this->t('Failed to generate elements due to "%error".', ['%error' => $e->getMessage()]));
+    }
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/BlockContentDevelGenerate.php

@@ -0,0 +1,493 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\block_content\BlockContentInterface;
+use Drupal\content_translation\ContentTranslationManagerInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
+use Drupal\Core\Extension\ExtensionPathResolver;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a BlockContentDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "block_content",
+ *   label = @Translation("Block Content"),
+ *   description = @Translation("Generate a given number of Block content blocks. Optionally delete current blocks."),
+ *   url = "block-content",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 50,
+ *     "kill" = FALSE,
+ *     "title_length" = 4,
+ *     "add_type_label" = FALSE,
+ *     "reusable" = TRUE
+ *   },
+ * )
+ */
+class BlockContentDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The block content storage.
+   */
+  protected EntityStorageInterface $blockContentStorage;
+
+  /**
+   * The block content type storage.
+   */
+  protected EntityStorageInterface $blockContentTypeStorage;
+
+  /**
+   * The extension path resolver service.
+   */
+  protected ExtensionPathResolver $extensionPathResolver;
+
+  /**
+   * The entity type bundle info service.
+   */
+  protected EntityTypeBundleInfoInterface $entityTypeBundleInfo;
+
+  /**
+   * The content translation manager.
+   */
+  protected ?ContentTranslationManagerInterface $contentTranslationManager;
+
+  /**
+   * The Drush batch flag.
+   */
+  protected bool $drushBatch = FALSE;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+
+    // @phpstan-ignore ternary.alwaysTrue (False positive)
+    $content_translation_manager = $container->has('content_translation.manager') ? $container->get('content_translation.manager') : NULL;
+
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->blockContentStorage = $entity_type_manager->getStorage('block_content');
+    $instance->blockContentTypeStorage = $entity_type_manager->getStorage('block_content_type');
+    $instance->extensionPathResolver = $container->get('extension.path.resolver');
+    $instance->entityTypeBundleInfo = $container->get('entity_type.bundle.info');
+    $instance->contentTranslationManager = $content_translation_manager;
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    /** @var \Drupal\block_content\BlockContentTypeInterface[] $blockTypes */
+    $blockTypes = $this->blockContentTypeStorage->loadMultiple();
+    $options = [];
+
+    foreach ($blockTypes as $type) {
+      $options[$type->id()] = [
+        'type' => [
+          'label' => $type->label(),
+          'description' => $type->getDescription(),
+        ],
+      ];
+    }
+
+    $header = [
+      'type' => $this->t('Block Content type'),
+      'description' => $this->t('Description'),
+    ];
+
+    $form['block_types'] = [
+      '#type' => 'tableselect',
+      '#header' => $header,
+      '#options' => $options,
+    ];
+
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('<strong>Delete all content</strong> in these block types before generating new content.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('How many blocks would you like to generate?'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+
+    $form['title_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum number of words in block descriptions'),
+      '#default_value' => $this->getSetting('title_length'),
+      '#required' => TRUE,
+      '#min' => 1,
+      '#max' => 255,
+    ];
+
+    $form['skip_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Fields to leave empty'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be skipped and have a default value in the generated content.'),
+      '#default_value' => NULL,
+    ];
+    $form['base_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Base fields to populate'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be populated.'),
+      '#default_value' => NULL,
+    ];
+
+    $form['reusable'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Reusable blocks'),
+      '#description' => $this->t('This will mark the blocks to be created as reusable.'),
+      '#default_value' => $this->getSetting('reusable'),
+
+    ];
+    $form['add_type_label'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Prefix the title with the block type label.'),
+      '#description' => $this->t('This will not count against the maximum number of title words specified above.'),
+      '#default_value' => $this->getSetting('add_type_label'),
+    ];
+
+    // Add the language and translation options.
+    $form += $this->getLanguageForm('blocks');
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsFormValidate(array $form, FormStateInterface $form_state): void {
+    if (array_filter($form_state->getValue('block_types')) === []) {
+      $form_state->setErrorByName('block_types', $this->t('Please select at least one block type'));
+    }
+
+    $skip_fields = is_null($form_state->getValue('skip_fields')) ? [] : self::csvToArray($form_state->getValue('skip_fields'));
+    $base_fields = is_null($form_state->getValue('base_fields')) ? [] : self::csvToArray($form_state->getValue('base_fields'));
+    $form_state->setValue('skip_fields', $skip_fields);
+    $form_state->setValue('base_fields', $base_fields);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    $add_language = self::csvToArray($options['languages']);
+    // Intersect with the enabled languages to make sure the language args
+    // passed are actually enabled.
+    $valid_languages = array_keys($this->languageManager->getLanguages(LanguageInterface::STATE_ALL));
+    $values['add_language'] = array_intersect($add_language, $valid_languages);
+
+    $translate_language = self::csvToArray($options['translations']);
+    $values['translate_language'] = array_intersect($translate_language, $valid_languages);
+
+    $values['add_type_label'] = $options['add-type-label'];
+    $values['kill'] = $options['kill'];
+    $values['feedback'] = $options['feedback'];
+    $values['skip_fields'] = is_null($options['skip-fields']) ? [] : self::csvToArray($options['skip-fields']);
+    $values['base_fields'] = is_null($options['base-fields']) ? [] : self::csvToArray($options['base-fields']);
+    $values['title_length'] = 6;
+    $values['num'] = array_shift($args);
+    $values['max_comments'] = array_shift($args);
+
+    $all_types = array_keys($this->blockContentGetBundles());
+    $selected_types = self::csvToArray($options['block_types']);
+
+    if ($selected_types === []) {
+      throw new \Exception(dt('No Block content types available'));
+    }
+
+    $values['block_types'] = array_combine($selected_types, $selected_types);
+    $block_types = array_filter($values['block_types']);
+
+    if (!empty($values['kill']) && $block_types === []) {
+      throw new \Exception(dt('To delete content, please provide the Block content types (--bundles)'));
+    }
+
+    // Checks for any missing block content types before generating blocks.
+    if (array_diff($block_types, $all_types) !== []) {
+      throw new \Exception(dt('One or more block content types have been entered that don\'t exist on this site'));
+    }
+
+    if ($this->isBatch($values['num'])) {
+      $this->drushBatch = TRUE;
+    }
+
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    if ($this->isBatch($values['num'])) {
+      $this->generateBatchContent($values);
+    }
+    else {
+      $this->generateContent($values);
+    }
+  }
+
+  /**
+   * Generate content in batch mode.
+   *
+   * This method is used when the number of elements is 50 or more.
+   */
+  private function generateBatchContent(array $values): void {
+    $operations = [];
+
+    // Remove unselected block content types.
+    $values['block_types'] = array_filter($values['block_types']);
+    // If it is drushBatch then this operation is already run in the
+    // self::validateDrushParams().
+    // Add the kill operation.
+    if ($values['kill']) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchContentKill', $values],
+      ];
+    }
+
+    // Add the operations to create the blocks.
+    for ($num = 0; $num < $values['num']; ++$num) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchContentAddBlock', $values],
+      ];
+    }
+
+    // Set the batch.
+    $batch = [
+      'title' => $this->t('Generating Content'),
+      'operations' => $operations,
+      'finished' => 'devel_generate_batch_finished',
+      'file' => $this->extensionPathResolver->getPath('module', 'devel_generate') . '/devel_generate.batch.inc',
+    ];
+
+    batch_set($batch);
+    if ($this->drushBatch) {
+      drush_backend_batch_process();
+    }
+  }
+
+  /**
+   * Batch wrapper for calling ContentAddBlock.
+   */
+  public function batchContentAddBlock(array $vars, array &$context): void {
+    if (!isset($context['results']['num'])) {
+      $context['results']['num'] = 0;
+    }
+
+    if ($this->drushBatch) {
+      ++$context['results']['num'];
+      $this->develGenerateContentAddBlock($vars);
+    }
+    else {
+      $context['results'] = $vars;
+      $this->develGenerateContentAddBlock($context['results']);
+    }
+
+    if (!empty($vars['num_translations'])) {
+      $context['results']['num_translations'] += $vars['num_translations'];
+    }
+  }
+
+  /**
+   * Batch wrapper for calling ContentKill.
+   */
+  public function batchContentKill(array $vars, array &$context): void {
+    if ($this->drushBatch) {
+      $this->contentKill($vars);
+    }
+    else {
+      $context['results'] = $vars;
+      $this->contentKill($context['results']);
+    }
+  }
+
+  /**
+   * Generate content when not in batch mode.
+   *
+   * This method is used when the number of elements is under 50.
+   */
+  private function generateContent(array $values): void {
+    $values['block_types'] = array_filter($values['block_types']);
+    if (!empty($values['kill']) && $values['block_types']) {
+      $this->contentKill($values);
+    }
+
+    if (isset($values['block_types']) && $values['block_types'] !== []) {
+      $start = time();
+      $values['num_translations'] = 0;
+      for ($i = 1; $i <= $values['num']; ++$i) {
+        $this->develGenerateContentAddBlock($values);
+        if (isset($values['feedback']) && $i % $values['feedback'] == 0) {
+          $now = time();
+          $options = [
+            '@feedback' => $values['feedback'],
+            '@rate' => ($values['feedback'] * 60) / ($now - $start),
+          ];
+          $this->messenger->addStatus(dt('Completed @feedback blocks (@rate blocks/min)', $options));
+          $start = $now;
+        }
+      }
+    }
+
+    $this->setMessage($this->formatPlural($values['num'], 'Created 1 block', 'Created @count blocks'));
+    if ($values['num_translations'] > 0) {
+      $this->setMessage($this->formatPlural($values['num_translations'], 'Created 1 block translation', 'Created @count block translations'));
+    }
+  }
+
+  /**
+   * Create one block. Used by both batch and non-batch code branches.
+   *
+   * @param array $results
+   *   Results information.
+   */
+  protected function develGenerateContentAddBlock(array &$results): void {
+    if (!isset($results['time_range'])) {
+      $results['time_range'] = 0;
+    }
+
+    $block_type = array_rand($results['block_types']);
+
+    // Add the block type label if required.
+    $title_prefix = $results['add_type_label'] ? $this->blockContentTypeStorage->load($block_type)->label() . ' - ' : '';
+
+    $values = [
+      'info' => $title_prefix . $this->getRandom()->sentences(mt_rand(1, $results['title_length']), TRUE),
+      'type' => $block_type,
+      // A flag to let hook_block_content_insert() implementations know that this is a generated block.
+      'devel_generate' => $results,
+    ];
+
+    if (isset($results['add_language'])) {
+      $values['langcode'] = $this->getLangcode($results['add_language']);
+    }
+
+    if (isset($results['reusable'])) {
+      $values['reusable'] = (int) $results['reusable'];
+    }
+
+    /** @var \Drupal\block_content\BlockContentInterface $block */
+    $block = $this->blockContentStorage->create($values);
+
+    // Populate non-skipped fields with sample values.
+    $this->populateFields($block, $results['skip_fields'], $results['base_fields']);
+
+    // Remove the fields which are intended to have no value.
+    foreach ($results['skip_fields'] as $field) {
+      unset($block->$field);
+    }
+
+    $block->save();
+
+    // Add translations.
+    $this->develGenerateContentAddBlockTranslation($results, $block);
+  }
+
+  /**
+   * Create translation for the given block.
+   *
+   * @param array $results
+   *   Results array.
+   * @param \Drupal\block_content\BlockContentInterface $block
+   *   Block to add translations to.
+   *
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   */
+  protected function develGenerateContentAddBlockTranslation(array &$results, BlockContentInterface $block): void {
+    if (empty($results['translate_language'])) {
+      return;
+    }
+
+    if (is_null($this->contentTranslationManager)) {
+      return;
+    }
+
+    if (!$this->contentTranslationManager->isEnabled('block_content', $block->bundle())) {
+      return;
+    }
+
+    if ($block->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_SPECIFIED
+      || $block->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_APPLICABLE) {
+      return;
+    }
+
+    if (!isset($results['num_translations'])) {
+      $results['num_translations'] = 0;
+    }
+
+    // Translate the block to each target language.
+    $skip_languages = [
+      LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      LanguageInterface::LANGCODE_NOT_APPLICABLE,
+      $block->get('langcode')->getLangcode(),
+    ];
+    foreach ($results['translate_language'] as $langcode) {
+      if (in_array($langcode, $skip_languages)) {
+        continue;
+      }
+
+      $translation_block = $block->addTranslation($langcode);
+      $translation_block->setInfo($block->label() . ' (' . $langcode . ')');
+      $this->populateFields($translation_block);
+      $translation_block->save();
+
+      ++$results['num_translations'];
+    }
+  }
+
+  /**
+   * Deletes all blocks of given block content types.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   */
+  protected function contentKill(array $values): void {
+    $bids = $this->blockContentStorage->getQuery()
+      ->condition('type', $values['block_types'], 'IN')
+      ->accessCheck(FALSE)
+      ->execute();
+
+    if (!empty($bids)) {
+      $blocks = $this->blockContentStorage->loadMultiple($bids);
+      $this->blockContentStorage->delete($blocks);
+      $this->setMessage($this->t('Deleted %count blocks.', ['%count' => count($bids)]));
+    }
+  }
+
+  /**
+   * Determines if the content should be generated in batch mode.
+   */
+  protected function isBatch($content_count): bool {
+    return $content_count >= 50;
+  }
+
+  /**
+   * Returns a list of available block content type names.
+   *
+   * This list can include types that are queued for addition or deletion.
+   *
+   * @return string[]
+   *   An array of block content type labels,
+   *   keyed by the block content type name.
+   */
+  public function blockContentGetBundles(): array {
+    return array_map(static fn($bundle_info) => $bundle_info['label'], $this->entityTypeBundleInfo->getBundleInfo('block_content'));
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/ContentDevelGenerate.php

@@ -0,0 +1,888 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\comment\CommentManagerInterface;
+use Drupal\comment\Plugin\Field\FieldType\CommentItemInterface;
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\Component\Utility\Random;
+use Drupal\content_translation\ContentTranslationManagerInterface;
+use Drupal\Core\Database\Connection;
+use Drupal\Core\Datetime\DateFormatterInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Extension\ExtensionPathResolver;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Routing\UrlGeneratorInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\node\NodeInterface;
+use Drupal\node\NodeStorageInterface;
+use Drupal\path_alias\PathAliasStorage;
+use Drupal\user\RoleStorageInterface;
+use Drupal\user\UserStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a ContentDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "content",
+ *   label = @Translation("content"),
+ *   description = @Translation("Generate a given number of content. Optionally delete current content."),
+ *   url = "content",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 50,
+ *     "kill" = FALSE,
+ *     "max_comments" = 0,
+ *     "title_length" = 4,
+ *     "add_type_label" = FALSE
+ *   },
+ *   dependencies = {
+ *     "node",
+ *   },
+ * )
+ */
+class ContentDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The node storage.
+   */
+  protected NodeStorageInterface $nodeStorage;
+
+  /**
+   * The node type storage.
+   */
+  protected EntityStorageInterface $nodeTypeStorage;
+
+  /**
+   * The user storage.
+   */
+  protected UserStorageInterface $userStorage;
+
+  /**
+   * The url generator service.
+   */
+  protected UrlGeneratorInterface $urlGenerator;
+
+  /**
+   * The alias storage.
+   */
+  protected PathAliasStorage $aliasStorage;
+
+  /**
+   * The date formatter service.
+   */
+  protected DateFormatterInterface $dateFormatter;
+
+  /**
+   * Provides system time.
+   */
+  protected TimeInterface $time;
+
+  /**
+   * Database connection.
+   */
+  protected Connection $database;
+
+  /**
+   * The extension path resolver service.
+   */
+  protected ExtensionPathResolver $extensionPathResolver;
+
+  /**
+   * The role storage.
+   */
+  protected RoleStorageInterface $roleStorage;
+
+  /**
+   * The comment manager service.
+   */
+  protected ?CommentManagerInterface $commentManager;
+
+  /**
+   * The content translation manager.
+   */
+  protected ?ContentTranslationManagerInterface $contentTranslationManager;
+
+  /**
+   * The Drush batch flag.
+   */
+  protected bool $drushBatch = FALSE;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+
+    // @phpstan-ignore ternary.alwaysTrue (False positive)
+    $comment_manager = $container->has('comment.manager') ? $container->get('comment.manager') : NULL;
+
+    // @phpstan-ignore ternary.alwaysTrue (False positive)
+    $content_translation_manager = $container->has('content_translation.manager') ? $container->get('content_translation.manager') : NULL;
+
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->nodeTypeStorage = $entity_type_manager->getStorage('node_type');
+    $instance->nodeStorage = $entity_type_manager->getStorage('node');
+    $instance->userStorage = $entity_type_manager->getStorage('user');
+    $instance->urlGenerator = $container->get('url_generator');
+    $instance->aliasStorage = $entity_type_manager->getStorage('path_alias');
+    $instance->dateFormatter = $container->get('date.formatter');
+    $instance->time = $container->get('datetime.time');
+    $instance->database = $container->get('database');
+    $instance->extensionPathResolver = $container->get('extension.path.resolver');
+    $instance->roleStorage = $entity_type_manager->getStorage('user_role');
+    $instance->commentManager = $comment_manager;
+    $instance->contentTranslationManager = $content_translation_manager;
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $types = $this->nodeTypeStorage->loadMultiple();
+
+    if (empty($types)) {
+      $create_url = $this->urlGenerator->generateFromRoute('node.type_add');
+      $this->setMessage($this->t('You do not have any content types that can be generated. <a href=":create-type">Go create a new content type</a>', [':create-type' => $create_url]), 'error');
+      return [];
+    }
+
+    $options = [];
+
+    foreach ($types as $type) {
+      $options[$type->id()] = [
+        'type' => ['#markup' => $type->label()],
+      ];
+      if ($this->commentManager instanceof CommentManagerInterface) {
+        $comment_fields = $this->commentManager->getFields('node');
+        $map = [$this->t('Hidden'), $this->t('Closed'), $this->t('Open')];
+
+        $fields = [];
+        foreach ($comment_fields as $field_name => $info) {
+          // Find all comment fields for the bundle.
+          if (in_array($type->id(), $info['bundles'])) {
+            $instance = FieldConfig::loadByName('node', $type->id(), $field_name);
+            $default_value = $instance->getDefaultValueLiteral();
+            $default_mode = reset($default_value);
+            $fields[] = new FormattableMarkup('@field: @state', [
+              '@field' => $instance->label(),
+              '@state' => $map[$default_mode['status']],
+            ]);
+          }
+        }
+
+        // @todo Refactor display of comment fields.
+        if ($fields !== []) {
+          $options[$type->id()]['comments'] = [
+            'data' => [
+              '#theme' => 'item_list',
+              '#items' => $fields,
+            ],
+          ];
+        }
+        else {
+          $options[$type->id()]['comments'] = $this->t('No comment fields');
+        }
+      }
+    }
+
+    $header = [
+      'type' => $this->t('Content type'),
+    ];
+    if ($this->commentManager instanceof CommentManagerInterface) {
+      $header['comments'] = [
+        'data' => $this->t('Comments'),
+        'class' => [RESPONSIVE_PRIORITY_MEDIUM],
+      ];
+    }
+
+    $form['node_types'] = [
+      '#type' => 'tableselect',
+      '#header' => $header,
+      '#options' => $options,
+    ];
+
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('<strong>Delete all content</strong> in these content types before generating new content.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('How many nodes would you like to generate?'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+
+    $options = [1 => $this->t('Now')];
+    foreach ([3600, 86400, 604800, 2592000, 31536000] as $interval) {
+      $options[$interval] = $this->dateFormatter->formatInterval($interval, 1) . ' ' . $this->t('ago');
+    }
+
+    $form['time_range'] = [
+      '#type' => 'select',
+      '#title' => $this->t('How far back in time should the nodes be dated?'),
+      '#description' => $this->t('Node creation dates will be distributed randomly from the current time, back to the selected time.'),
+      '#options' => $options,
+      '#default_value' => 604800,
+    ];
+
+    $form['max_comments'] = [
+      '#type' => $this->moduleHandler->moduleExists('comment') ? 'number' : 'value',
+      '#title' => $this->t('Maximum number of comments per node.'),
+      '#description' => $this->t('You must also enable comments for the content types you are generating. Note that some nodes will randomly receive zero comments. Some will receive the max.'),
+      '#default_value' => $this->getSetting('max_comments'),
+      '#min' => 0,
+      '#access' => $this->moduleHandler->moduleExists('comment'),
+    ];
+    $form['title_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum number of words in titles'),
+      '#default_value' => $this->getSetting('title_length'),
+      '#required' => TRUE,
+      '#min' => 1,
+      '#max' => 255,
+    ];
+    $form['skip_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Fields to leave empty'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be skipped and have a default value in the generated content.'),
+      '#default_value' => NULL,
+    ];
+    $form['base_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Base fields to populate'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be populated.'),
+      '#default_value' => NULL,
+    ];
+    $form['add_type_label'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Prefix the title with the content type label.'),
+      '#description' => $this->t('This will not count against the maximum number of title words specified above.'),
+      '#default_value' => $this->getSetting('add_type_label'),
+    ];
+    $form['add_alias'] = [
+      '#type' => 'checkbox',
+      '#disabled' => !$this->moduleHandler->moduleExists('path'),
+      '#description' => $this->t('Requires path.module'),
+      '#title' => $this->t('Add an url alias for each node.'),
+      '#default_value' => FALSE,
+    ];
+    $form['add_statistics'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Add statistics for each node (node_counter table).'),
+      '#default_value' => TRUE,
+      '#access' => $this->moduleHandler->moduleExists('statistics'),
+    ];
+
+    // Add the language and translation options.
+    $form += $this->getLanguageForm('nodes');
+
+    // Add the user selection checkboxes.
+    $author_header = [
+      'id' => $this->t('User ID'),
+      'user' => $this->t('Name'),
+      'role' => $this->t('Role(s)'),
+    ];
+
+    $num_users = $this->database->select('users')
+      ->countQuery()
+      ->execute()
+      ->fetchField();
+    $author_form_limit = 50;
+    $query = $this->database->select('users', 'u')
+      ->fields('u', ['uid'])
+      ->range(0, $author_form_limit)
+      ->orderBy('uid');
+    $uids = $query->execute()->fetchCol();
+
+    $author_rows = [];
+    foreach ($uids as $uid) {
+      /** @var \Drupal\user\UserInterface $user */
+      $user = $this->userStorage->load($uid);
+      $author_rows[$user->id()] = [
+        'id' => ['#markup' => $user->id()],
+        'user' => ['#markup' => $user->getAccountName()],
+        'role' => ['#markup' => implode(", ", $user->getRoles())],
+      ];
+    }
+
+    $form['authors-wrap'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Users'),
+      '#open' => FALSE,
+      '#description' => $this->t('Select users for randomly assigning as authors of the generated content.')
+      . ($num_users > $author_form_limit ? ' ' . $this->t('The site has @num_users users, only the first @$author_form_limit are shown and selectable here.', ['@num_users' => $num_users, '@$author_form_limit' => $author_form_limit]) : ''),
+    ];
+
+    $form['authors-wrap']['authors'] = [
+      '#type' => 'tableselect',
+      '#header' => $author_header,
+      '#options' => $author_rows,
+    ];
+
+    $role_rows = [];
+    $roles = array_map(static fn($role): string => $role->label(), $this->roleStorage->loadMultiple());
+    foreach ($roles as $role_id => $role_name) {
+      $role_rows[$role_id] = [
+        'id' => ['#markup' => $role_id],
+        'role' => ['#markup' => $role_name],
+      ];
+    }
+
+    $form['authors-wrap']['roles'] = [
+      '#type' => 'tableselect',
+      '#header' => [
+        'id' => $this->t('Role ID'),
+        'role' => $this->t('Role Description'),
+      ],
+      '#options' => $role_rows,
+      '#prefix' => $this->t('Specify the roles that randomly selected authors must have.'),
+      '#suffix' => $this->t('You can select users and roles. Authors will be randomly selected that match at least one of the criteria. Leave <em>both</em> selections unchecked to use a random selection of @$author_form_limit users, including Anonymous.', ['@$author_form_limit' => $author_form_limit]),
+    ];
+
+    $form['#redirect'] = FALSE;
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsFormValidate(array $form, FormStateInterface $form_state): void {
+    if (array_filter($form_state->getValue('node_types')) === []) {
+      $form_state->setErrorByName('node_types', $this->t('Please select at least one content type'));
+    }
+
+    $skip_fields = is_null($form_state->getValue('skip_fields')) ? [] : self::csvToArray($form_state->getValue('skip_fields'));
+    $base_fields = is_null($form_state->getValue('base_fields')) ? [] : self::csvToArray($form_state->getValue('base_fields'));
+    $form_state->setValue('skip_fields', $skip_fields);
+    $form_state->setValue('base_fields', $base_fields);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    if ($this->isBatch($values['num'], $values['max_comments'])) {
+      $this->generateBatchContent($values);
+    }
+    else {
+      $this->generateContent($values);
+    }
+  }
+
+  /**
+   * Generate content when not in batch mode.
+   *
+   * This method is used when the number of elements is under 50.
+   */
+  private function generateContent(array $values): void {
+    $values['node_types'] = array_filter($values['node_types']);
+    if (!empty($values['kill']) && $values['node_types']) {
+      $this->contentKill($values);
+    }
+
+    if ($values['node_types'] !== []) {
+      // Generate nodes.
+      $this->develGenerateContentPreNode($values);
+      $start = time();
+      $values['num_translations'] = 0;
+      for ($i = 1; $i <= $values['num']; ++$i) {
+        $this->develGenerateContentAddNode($values);
+        if (isset($values['feedback']) && $i % $values['feedback'] == 0) {
+          $now = time();
+          $options = [
+            '@feedback' => $values['feedback'],
+            '@rate' => ($values['feedback'] * 60) / ($now - $start),
+          ];
+          $this->messenger->addStatus(dt('Completed @feedback nodes (@rate nodes/min)', $options));
+          $start = $now;
+        }
+      }
+    }
+
+    $this->setMessage($this->formatPlural($values['num'], 'Created 1 node', 'Created @count nodes'));
+    if ($values['num_translations'] > 0) {
+      $this->setMessage($this->formatPlural($values['num_translations'], 'Created 1 node translation', 'Created @count node translations'));
+    }
+  }
+
+  /**
+   * Generate content in batch mode.
+   *
+   * This method is used when the number of elements is 50 or more.
+   */
+  private function generateBatchContent(array $values): void {
+    $operations = [];
+
+    // Remove unselected node types.
+    $values['node_types'] = array_filter($values['node_types']);
+    // If it is drushBatch then this operation is already run in the
+    // self::validateDrushParams().
+    if (!$this->drushBatch) {
+      // Setup the batch operations and save the variables.
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchContentPreNode', $values],
+      ];
+    }
+
+    // Add the kill operation.
+    if ($values['kill']) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchContentKill', $values],
+      ];
+    }
+
+    // Add the operations to create the nodes.
+    for ($num = 0; $num < $values['num']; ++$num) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchContentAddNode', $values],
+      ];
+    }
+
+    // Set the batch.
+    $batch = [
+      'title' => $this->t('Generating Content'),
+      'operations' => $operations,
+      'finished' => 'devel_generate_batch_finished',
+      'file' => $this->extensionPathResolver->getPath('module', 'devel_generate') . '/devel_generate.batch.inc',
+    ];
+
+    batch_set($batch);
+    if ($this->drushBatch) {
+      drush_backend_batch_process();
+    }
+  }
+
+  /**
+   * Batch wrapper for calling ContentPreNode.
+   */
+  public function batchContentPreNode($vars, array &$context): void {
+    $context['results'] = $vars;
+    $context['results']['num'] = 0;
+    $context['results']['num_translations'] = 0;
+    $this->develGenerateContentPreNode($context['results']);
+  }
+
+  /**
+   * Batch wrapper for calling ContentAddNode.
+   */
+  public function batchContentAddNode(array $vars, array &$context): void {
+    if ($this->drushBatch) {
+      $this->develGenerateContentAddNode($vars);
+    }
+    else {
+      $this->develGenerateContentAddNode($context['results']);
+    }
+
+    if (!isset($context['results']['num'])) {
+      $context['results']['num'] = 0;
+    }
+
+    ++$context['results']['num'];
+    if (!empty($vars['num_translations'])) {
+      $context['results']['num_translations'] += $vars['num_translations'];
+    }
+  }
+
+  /**
+   * Batch wrapper for calling ContentKill.
+   */
+  public function batchContentKill(array $vars, array &$context): void {
+    if ($this->drushBatch) {
+      $this->contentKill($vars);
+    }
+    else {
+      $this->contentKill($context['results']);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    $add_language = self::csvToArray($options['languages']);
+    // Intersect with the enabled languages to make sure the language args
+    // passed are actually enabled.
+    $valid_languages = array_keys($this->languageManager->getLanguages(LanguageInterface::STATE_ALL));
+    $values['add_language'] = array_intersect($add_language, $valid_languages);
+
+    $translate_language = self::csvToArray($options['translations']);
+    $values['translate_language'] = array_intersect($translate_language, $valid_languages);
+
+    $values['add_type_label'] = $options['add-type-label'];
+    $values['kill'] = $options['kill'];
+    $values['feedback'] = $options['feedback'];
+    $values['skip_fields'] = is_null($options['skip-fields']) ? [] : self::csvToArray($options['skip-fields']);
+    $values['base_fields'] = is_null($options['base-fields']) ? [] : self::csvToArray($options['base-fields']);
+    $values['title_length'] = 6;
+    $values['num'] = array_shift($args);
+    $values['max_comments'] = array_shift($args);
+    // Do not use csvToArray for 'authors' because it removes '0' values.
+    $values['authors'] = is_null($options['authors']) ? [] : explode(',', $options['authors']);
+    $values['roles'] = self::csvToArray($options['roles']);
+
+    $all_types = array_keys(node_type_get_names());
+    $default_types = array_intersect(['page', 'article'], $all_types);
+    $selected_types = self::csvToArray($options['bundles'] ?: $default_types);
+
+    if ($selected_types === []) {
+      throw new \Exception(dt('No content types available'));
+    }
+
+    $values['node_types'] = array_combine($selected_types, $selected_types);
+    $node_types = array_filter($values['node_types']);
+
+    if (!empty($values['kill']) && $node_types === []) {
+      throw new \Exception(dt('To delete content, please provide the content types (--bundles)'));
+    }
+
+    // Checks for any missing content types before generating nodes.
+    if (array_diff($node_types, $all_types) !== []) {
+      throw new \Exception(dt('One or more content types have been entered that don\'t exist on this site'));
+    }
+
+    if ($this->isBatch($values['num'], $values['max_comments'])) {
+      $this->drushBatch = TRUE;
+      $this->develGenerateContentPreNode($values);
+    }
+
+    return $values;
+  }
+
+  /**
+   * Determines if the content should be generated in batch mode.
+   */
+  protected function isBatch(int $content_count, int $comment_count): bool {
+    return $content_count >= 50 || $comment_count >= 10;
+  }
+
+  /**
+   * Deletes all nodes of given node types.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   */
+  protected function contentKill(array $values): void {
+    $nids = $this->nodeStorage->getQuery()
+      ->condition('type', $values['node_types'], 'IN')
+      ->accessCheck(FALSE)
+      ->execute();
+
+    if (!empty($nids)) {
+      $nodes = $this->nodeStorage->loadMultiple($nids);
+      $this->nodeStorage->delete($nodes);
+      $this->setMessage($this->t('Deleted @count nodes.', ['@count' => count($nids)]));
+    }
+  }
+
+  /**
+   * Preprocesses $results before adding content.
+   *
+   * @param array $results
+   *   Results information.
+   */
+  protected function develGenerateContentPreNode(array &$results): void {
+    $authors = $results['authors'];
+    // Remove non-selected users. !== 0 will leave the Anonymous user in if it
+    // was selected on the form or entered in the drush parameters.
+    $authors = array_filter($authors, static fn($k): bool => $k !== 0);
+    // Likewise remove non-selected roles.
+    $roles = $results['roles'];
+    $roles = array_filter($roles, static fn($k): bool => $k !== 0);
+
+    // If specific roles have been selected then also add up to 50 users who
+    // have one of these roles. There is no direct way randomise the selection
+    // using entity queries, so we use a database query instead.
+    if ($roles !== [] && !in_array('authenticated', $roles)) {
+      $query = $this->database->select('user__roles', 'ur')
+        ->fields('ur', ['entity_id', 'roles_target_id'])
+        ->condition('roles_target_id', $roles, 'in')
+        ->range(0, 50)
+        ->orderRandom();
+      $uids = array_unique($query->execute()->fetchCol());
+      // If the 'anonymous' role is selected, then add '0' to the user ids. Also
+      // do this if no users were specified and none were found with the role(s)
+      // requested. This makes it clear that no users were found. It would be
+      // worse to fall through and select completely random users who do not
+      // have any of the roles requested.
+      if (in_array('anonymous', $roles) || ($authors === [] && $uids === [])) {
+        $uids[] = '0';
+      }
+
+      $authors = array_unique(array_merge($authors, $uids));
+    }
+
+    // If still no authors have been collected, or the 'authenticated' role was
+    // requested then add a random set of users up to a maximum of 50.
+    if ($authors === [] || in_array('authenticated', $roles)) {
+      $query = $this->database->select('users', 'u')
+        ->fields('u', ['uid'])
+        ->range(0, 50)
+        ->orderRandom();
+      $uids = $query->execute()->fetchCol();
+      $authors = array_unique(array_merge($authors, $uids));
+    }
+
+    $results['users'] = $authors;
+  }
+
+  /**
+   * Create one node. Used by both batch and non-batch code branches.
+   *
+   * @param array $results
+   *   Results information.
+   */
+  protected function develGenerateContentAddNode(array &$results): void {
+    if (!isset($results['time_range'])) {
+      $results['time_range'] = 0;
+    }
+
+    $users = $results['users'];
+
+    $node_type = array_rand($results['node_types']);
+    $uid = $users[array_rand($users)];
+
+    // Add the content type label if required.
+    $title_prefix = $results['add_type_label'] ? $this->nodeTypeStorage->load($node_type)->label() . ' - ' : '';
+
+    $values = [
+      'nid' => NULL,
+      'type' => $node_type,
+      'title' => $title_prefix . $this->getRandom()->sentences(mt_rand(1, $results['title_length']), TRUE),
+      'uid' => $uid,
+      'revision' => mt_rand(0, 1),
+      'moderation_state' => 'published',
+      'status' => TRUE,
+      'promote' => mt_rand(0, 1),
+      'created' => $this->time->getRequestTime() - mt_rand(0, $results['time_range']),
+      // A flag to let hook_node_insert() implementations know that this is a
+      // generated node.
+      'devel_generate' => $results,
+    ];
+
+    if (isset($results['add_language'])) {
+      $values['langcode'] = $this->getLangcode($results['add_language']);
+    }
+
+    /** @var \Drupal\node\NodeInterface $node */
+    $node = $this->nodeStorage->create($values);
+
+    // Populate non-skipped fields with sample values.
+    $this->populateFields($node, $results['skip_fields'], $results['base_fields']);
+
+    // Remove the fields which are intended to have no value.
+    foreach ($results['skip_fields'] as $field) {
+      unset($node->$field);
+    }
+
+    $node->save();
+    $this->insertNodeData($node);
+
+    // Add url alias if required.
+    if (!empty($results['add_alias'])) {
+      $path_alias = $this->aliasStorage->create([
+        'path' => '/node/' . $node->id(),
+        'alias' => '/node-' . $node->id() . '-' . $node->bundle(),
+        'langcode' => $values['langcode'] ?? LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      ]);
+      $path_alias->save();
+    }
+
+    // Add translations.
+    $this->develGenerateContentAddNodeTranslation($results, $node);
+  }
+
+  /**
+   * Create translation for the given node.
+   *
+   * @param array $results
+   *   Results array.
+   * @param \Drupal\node\NodeInterface $node
+   *   Node to add translations to.
+   *
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   */
+  protected function develGenerateContentAddNodeTranslation(array &$results, NodeInterface $node): void {
+    if (empty($results['translate_language'])) {
+      return;
+    }
+
+    if (is_null($this->contentTranslationManager)) {
+      return;
+    }
+
+    if (!$this->contentTranslationManager->isEnabled('node', $node->getType())) {
+      return;
+    }
+
+    if ($node->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_SPECIFIED
+      || $node->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_APPLICABLE) {
+      return;
+    }
+
+    if (!isset($results['num_translations'])) {
+      $results['num_translations'] = 0;
+    }
+
+    // Translate node to each target language.
+    $skip_languages = [
+      LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      LanguageInterface::LANGCODE_NOT_APPLICABLE,
+      $node->get('langcode')->getLangcode(),
+    ];
+    foreach ($results['translate_language'] as $langcode) {
+      if (in_array($langcode, $skip_languages)) {
+        continue;
+      }
+
+      $translation_node = $node->addTranslation($langcode);
+      $translation_node->setTitle($node->getTitle() . ' (' . $langcode . ')');
+      $this->populateFields($translation_node);
+      $translation_node->save();
+      if ($translation_node->id() > 0 && !empty($results['add_alias'])) {
+        $path_alias = $this->aliasStorage->create([
+          'path' => '/node/' . $translation_node->id(),
+          'alias' => '/node-' . $translation_node->id() . '-' . $translation_node->bundle() . '-' . $langcode,
+          'langcode' => $langcode,
+        ]);
+        $path_alias->save();
+      }
+
+      ++$results['num_translations'];
+    }
+  }
+
+  private function insertNodeData(NodeInterface $node): void {
+    if (!isset($node->devel_generate)) {
+      return;
+    }
+
+    $results = $node->devel_generate;
+    if (!empty($results['max_comments'])) {
+      foreach ($node->getFieldDefinitions() as $field_name => $field_definition) {
+        if ($field_definition->getType() !== 'comment') {
+          continue;
+        }
+
+        if ($node->get($field_name)->getValue()[0]['status'] !== CommentItemInterface::OPEN) {
+          continue;
+        }
+
+        // Add comments for each comment field on entity.
+        $this->addNodeComments($node, $field_definition, $results['users'], $results['max_comments'], $results['title_length']);
+      }
+    }
+
+    if ($results['add_statistics']) {
+      $this->addNodeStatistics($node);
+    }
+  }
+
+  /**
+   * Create comments and add them to a node.
+   *
+   * @param \Drupal\node\NodeInterface $node
+   *   Node to add comments to.
+   * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
+   *   The field storage definition.
+   * @param array $users
+   *   Array of users to assign comment authors.
+   * @param int $max_comments
+   *   Max number of comments to generate per node.
+   * @param int $title_length
+   *   Max length of the title of the comments.
+   */
+  private function addNodeComments(NodeInterface $node, FieldDefinitionInterface $field_definition, array $users, int $max_comments, int $title_length = 8): void {
+    $parents = [];
+    $commentStorage = $this->entityTypeManager->getStorage('comment');
+    $field_name = $field_definition->getName();
+    $num_comments = mt_rand(0, $max_comments);
+    for ($i = 1; $i <= $num_comments; ++$i) {
+      $query = $commentStorage->getQuery();
+      switch ($i % 3) {
+        case 0:
+          // No parent.
+        case 1:
+          // Top level parent.
+          $parents = $query
+            ->condition('pid', 0)
+            ->condition('entity_id', $node->id())
+            ->condition('entity_type', 'node')
+            ->condition('field_name', $field_name)
+            ->range(0, 1)
+            ->accessCheck(FALSE)
+            ->execute();
+          break;
+
+        case 2:
+          // Non top level parent.
+          $parents = $query
+            ->condition('pid', 0, '>')
+            ->condition('entity_id', $node->id())
+            ->condition('entity_type', 'node')
+            ->condition('field_name', $field_name)
+            ->range(0, 1)
+            ->accessCheck(FALSE)
+            ->execute();
+          break;
+      }
+
+      $random = new Random();
+      $stub = [
+        'entity_type' => $node->getEntityTypeId(),
+        'entity_id' => $node->id(),
+        'field_name' => $field_name,
+        'name' => 'devel generate',
+        'mail' => 'devel_generate@example.com',
+        'timestamp' => mt_rand($node->getCreatedTime(), $this->time->getRequestTime()),
+        'subject' => substr($random->sentences(mt_rand(1, $title_length), TRUE), 0, 63),
+        'uid' => $users[array_rand($users)],
+        'langcode' => $node->language()->getId(),
+      ];
+      if ($parents) {
+        $stub['pid'] = current($parents);
+      }
+
+      $comment = $commentStorage->create($stub);
+
+      // Populate all core fields.
+      $this->populateFields($comment);
+      $comment->save();
+    }
+  }
+
+  /**
+   * Generate statistics information for a node.
+   *
+   * @param \Drupal\node\NodeInterface $node
+   *   A node object.
+   */
+  private function addNodeStatistics(NodeInterface $node): void {
+    if (!$this->moduleHandler->moduleExists('statistics')) {
+      return;
+    }
+
+    $statistic = [
+      'nid' => $node->id(),
+      'totalcount' => mt_rand(0, 500),
+      'timestamp' => $this->time->getRequestTime() - mt_rand(0, $node->getCreatedTime()),
+    ];
+    $statistic['daycount'] = mt_rand(0, $statistic['totalcount']);
+    $this->database->insert('node_counter')->fields($statistic)->execute();
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/MediaDevelGenerate.php

@@ -0,0 +1,534 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Core\Config\Entity\ConfigEntityStorageInterface;
+use Drupal\Core\Datetime\DateFormatterInterface;
+use Drupal\Core\Entity\ContentEntityStorageInterface;
+use Drupal\Core\Extension\ExtensionPathResolver;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Routing\UrlGeneratorInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\user\UserStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a plugin that generates media entities.
+ *
+ * @DevelGenerate(
+ *   id = "media",
+ *   label = @Translation("media"),
+ *   description = @Translation("Generate a given number of media entities."),
+ *   url = "media",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 50,
+ *     "kill" = FALSE,
+ *     "name_length" = 4,
+ *   },
+ *   dependencies = {
+ *     "media",
+ *   },
+ * )
+ */
+class MediaDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The media entity storage.
+   */
+  protected ContentEntityStorageInterface $mediaStorage;
+
+  /**
+   * The media type entity storage.
+   */
+  protected ConfigEntityStorageInterface $mediaTypeStorage;
+
+  /**
+   * The user entity storage.
+   */
+  protected UserStorageInterface $userStorage;
+
+  /**
+   * The url generator service.
+   */
+  protected UrlGeneratorInterface $urlGenerator;
+
+  /**
+   * The date formatter service.
+   */
+  protected DateFormatterInterface $dateFormatter;
+
+  /**
+   * The system time service.
+   */
+  protected TimeInterface $time;
+
+  /**
+   * The extension path resolver service.
+   */
+  protected ExtensionPathResolver $extensionPathResolver;
+
+  /**
+   * The Drush batch flag.
+   */
+  protected bool $drushBatch = FALSE;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->mediaStorage = $entity_type_manager->getStorage('media');
+    $instance->mediaTypeStorage = $entity_type_manager->getStorage('media_type');
+    $instance->userStorage = $entity_type_manager->getStorage('user');
+    $instance->urlGenerator = $container->get('url_generator');
+    $instance->dateFormatter = $container->get('date.formatter');
+    $instance->time = $container->get('datetime.time');
+    $instance->extensionPathResolver = $container->get('extension.path.resolver');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $types = $this->mediaTypeStorage->loadMultiple();
+
+    if (empty($types)) {
+      $create_url = $this->urlGenerator->generateFromRoute('entity.media_type.add_form');
+      $this->setMessage($this->t('You do not have any media types that can be generated. <a href=":url">Go create a new media type</a>', [
+        ':url' => $create_url,
+      ]), MessengerInterface::TYPE_ERROR);
+      return [];
+    }
+
+    $options = [];
+    foreach ($types as $type) {
+      $options[$type->id()] = ['type' => ['#markup' => $type->label()]];
+    }
+
+    $form['media_types'] = [
+      '#type' => 'tableselect',
+      '#header' => ['type' => $this->t('Media type')],
+      '#options' => $options,
+    ];
+
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('<strong>Delete all media</strong> in these types before generating new media.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('How many media items would you like to generate?'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+
+    $options = [1 => $this->t('Now')];
+    foreach ([3600, 86400, 604800, 2592000, 31536000] as $interval) {
+      $options[$interval] = $this->dateFormatter->formatInterval($interval, 1) . ' ' . $this->t('ago');
+    }
+
+    $form['time_range'] = [
+      '#type' => 'select',
+      '#title' => $this->t('How far back in time should the media be dated?'),
+      '#description' => $this->t('Media creation dates will be distributed randomly from the current time, back to the selected time.'),
+      '#options' => $options,
+      '#default_value' => 604800,
+    ];
+
+    $form['name_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum number of words in names'),
+      '#default_value' => $this->getSetting('name_length'),
+      '#required' => TRUE,
+      '#min' => 1,
+      '#max' => 255,
+    ];
+
+    $form['skip_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Fields to leave empty'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be skipped and have a default value in the generated content.'),
+      '#default_value' => NULL,
+    ];
+    $form['base_fields'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Base fields to populate'),
+      '#description' => $this->t('Enter the field names as a comma-separated list. These will be populated.'),
+      '#default_value' => NULL,
+    ];
+
+    $options = [];
+    // We always need a language.
+    $languages = $this->languageManager->getLanguages(LanguageInterface::STATE_ALL);
+    foreach ($languages as $langcode => $language) {
+      $options[$langcode] = $language->getName();
+    }
+
+    $form['add_language'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Set language on media'),
+      '#multiple' => TRUE,
+      '#description' => $this->t('Requires locale.module'),
+      '#options' => $options,
+      '#default_value' => [
+        $this->languageManager->getDefaultLanguage()->getId(),
+      ],
+    ];
+
+    $form['#redirect'] = FALSE;
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsFormValidate(array $form, FormStateInterface $form_state): void {
+    // Remove the media types not selected.
+    $media_types = array_filter($form_state->getValue('media_types'));
+    if ($media_types === []) {
+      $form_state->setErrorByName('media_types', $this->t('Please select at least one media type'));
+    }
+
+    // Store the normalized value back, in form state.
+    $form_state->setValue('media_types', array_combine($media_types, $media_types));
+
+    $skip_fields = is_null($form_state->getValue('skip_fields')) ? [] : self::csvToArray($form_state->getValue('skip_fields'));
+    $base_fields = is_null($form_state->getValue('base_fields')) ? [] : self::csvToArray($form_state->getValue('base_fields'));
+    $form_state->setValue('skip_fields', $skip_fields);
+    $form_state->setValue('base_fields', $base_fields);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    if ($this->isBatch($values['num'])) {
+      $this->generateBatchMedia($values);
+    }
+    else {
+      $this->generateMedia($values);
+    }
+  }
+
+  /**
+   * Method for creating media when number of elements is less than 50.
+   *
+   * @param array $values
+   *   Array of values submitted through a form.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *   Thrown if the storage handler couldn't be loaded.
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   *   Thrown if the entity type doesn't exist.
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   *   Thrown if the bundle does not exist or was needed but not specified.
+   */
+  protected function generateMedia(array $values): void {
+    if (!empty($values['kill']) && $values['media_types']) {
+      $this->mediaKill($values);
+    }
+
+    if (!empty($values['media_types'])) {
+      // Generate media items.
+      $this->preGenerate($values);
+      $start = time();
+      for ($i = 1; $i <= $values['num']; ++$i) {
+        $this->createMediaItem($values);
+        if (isset($values['feedback']) && $i % $values['feedback'] == 0) {
+          $now = time();
+          $this->messenger->addStatus(dt('Completed !feedback media items (!rate media/min)', [
+            '!feedback' => $values['feedback'],
+            '!rate' => ($values['feedback'] * 60) / ($now - $start),
+          ]));
+          $start = $now;
+        }
+      }
+    }
+
+    $this->setMessage($this->formatPlural($values['num'], '1 media item created.', 'Finished creating @count media items.'));
+  }
+
+  /**
+   * Method for creating media when number of elements is greater than 50.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   */
+  protected function generateBatchMedia(array $values): void {
+    $operations = [];
+
+    // Setup the batch operations and save the variables.
+    $operations[] = [
+      'devel_generate_operation',
+      [$this, 'batchPreGenerate', $values],
+    ];
+
+    // Add the kill operation.
+    if ($values['kill']) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchMediaKill', $values],
+      ];
+    }
+
+    // Add the operations to create the media.
+    for ($num = 0; $num < $values['num']; ++$num) {
+      $operations[] = [
+        'devel_generate_operation',
+        [$this, 'batchCreateMediaItem', $values],
+      ];
+    }
+
+    // Start the batch.
+    $batch = [
+      'title' => $this->t('Generating media items'),
+      'operations' => $operations,
+      'finished' => 'devel_generate_batch_finished',
+      'file' => $this->extensionPathResolver->getPath('module', 'devel_generate') . '/devel_generate.batch.inc',
+    ];
+    batch_set($batch);
+
+    if ($this->drushBatch) {
+      drush_backend_batch_process();
+    }
+  }
+
+  /**
+   * Provides a batch version of preGenerate().
+   *
+   * @param array $vars
+   *   The input values from the settings form.
+   * @param iterable $context
+   *   Batch job context.
+   *
+   * @see self::preGenerate()
+   */
+  public function batchPreGenerate(array $vars, iterable &$context): void {
+    $context['results'] = $vars;
+    $context['results']['num'] = 0;
+    $this->preGenerate($context['results']);
+  }
+
+  /**
+   * Provides a batch version of createMediaItem().
+   *
+   * @param array $vars
+   *   The input values from the settings form.
+   * @param iterable $context
+   *   Batch job context.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *   Thrown if the storage handler couldn't be loaded.
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   *   Thrown if the entity type doesn't exist.
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   *   Thrown if the bundle does not exist or was needed but not specified.
+   *
+   * @see self::createMediaItem()
+   */
+  public function batchCreateMediaItem(array $vars, iterable &$context): void {
+    if ($this->drushBatch) {
+      $this->createMediaItem($vars);
+    }
+    else {
+      $this->createMediaItem($context['results']);
+    }
+
+    if (!isset($context['results']['num'])) {
+      $context['results']['num'] = 0;
+    }
+
+    ++$context['results']['num'];
+  }
+
+  /**
+   * Provides a batch version of mediaKill().
+   *
+   * @param array $vars
+   *   The input values from the settings form.
+   * @param iterable $context
+   *   Batch job context.
+   *
+   * @see self::mediaKill()
+   */
+  public function batchMediaKill(array $vars, iterable &$context): void {
+    if ($this->drushBatch) {
+      $this->mediaKill($vars);
+    }
+    else {
+      $this->mediaKill($context['results']);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    $add_language = $options['languages'];
+    if (!empty($add_language)) {
+      $add_language = explode(',', str_replace(' ', '', $add_language));
+      // Intersect with the enabled languages to make sure the language args
+      // passed are actually enabled.
+      $values['values']['add_language'] = array_intersect($add_language, array_keys($this->languageManager->getLanguages(LanguageInterface::STATE_ALL)));
+    }
+
+    $values['kill'] = $options['kill'];
+    $values['feedback'] = $options['feedback'];
+    $values['name_length'] = 6;
+    $values['num'] = array_shift($args);
+
+    $values['skip_fields'] = is_null($options['skip-fields']) ? [] : self::csvToArray($options['skip-fields']);
+    $values['base_fields'] = is_null($options['base-fields']) ? [] : self::csvToArray($options['base-fields']);
+
+    $all_media_types = array_values($this->mediaTypeStorage->getQuery()->accessCheck(FALSE)->execute());
+    $requested_media_types = self::csvToArray($options['media-types'] ?: $all_media_types);
+
+    if ($requested_media_types === []) {
+      throw new \Exception(dt('No media types available'));
+    }
+
+    // Check for any missing media type.
+    if (($invalid_media_types = array_diff($requested_media_types, $all_media_types)) !== []) {
+      throw new \Exception("Requested media types don't exists: " . implode(', ', $invalid_media_types));
+    }
+
+    $values['media_types'] = array_combine($requested_media_types, $requested_media_types);
+
+    if ($this->isBatch($values['num'])) {
+      $this->drushBatch = TRUE;
+      $this->preGenerate($values);
+    }
+
+    return $values;
+  }
+
+  /**
+   * Deletes all media of given media media types.
+   *
+   * @param array $values
+   *   The input values from the settings form.
+   *
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   *   Thrown if the media type does not exist.
+   */
+  protected function mediaKill(array $values): void {
+    $mids = $this->mediaStorage->getQuery()
+      ->condition('bundle', $values['media_types'], 'IN')
+      ->accessCheck(FALSE)
+      ->execute();
+
+    if (!empty($mids)) {
+      $media = $this->mediaStorage->loadMultiple($mids);
+      $this->mediaStorage->delete($media);
+      $this->setMessage($this->t('Deleted %count media items.', ['%count' => count($mids)]));
+    }
+  }
+
+  /**
+   * Code to be run before generating items.
+   *
+   * Returns the same array passed in as parameter, but with an array of uids
+   * for the key 'users'.
+   *
+   * @param array $results
+   *   The input values from the settings form.
+   */
+  protected function preGenerate(array &$results): void {
+    // Get user id.
+    $users = array_values($this->userStorage->getQuery()
+      ->range(0, 50)
+      ->accessCheck(FALSE)
+      ->execute());
+    $users = array_merge($users, ['0']);
+    $results['users'] = $users;
+  }
+
+  /**
+   * Create one media item. Used by both batch and non-batch code branches.
+   *
+   * @param array $results
+   *   The input values from the settings form.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *   Thrown if the storage handler couldn't be loaded.
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   *   Thrown if the entity type doesn't exist.
+   * @throws \Drupal\Core\Entity\EntityStorageException
+   *   Thrown if the bundle does not exist or was needed but not specified.
+   */
+  protected function createMediaItem(array &$results): void {
+    if (!isset($results['time_range'])) {
+      $results['time_range'] = 0;
+    }
+
+    $media_type = array_rand($results['media_types']);
+    $uid = $results['users'][array_rand($results['users'])];
+
+    $media = $this->mediaStorage->create([
+      'bundle' => $media_type,
+      'name' => $this->getRandom()->sentences(mt_rand(1, $results['name_length']), TRUE),
+      'uid' => $uid,
+      'revision' => mt_rand(0, 1),
+      'status' => TRUE,
+      'moderation_state' => 'published',
+      'created' => $this->time->getRequestTime() - mt_rand(0, $results['time_range']),
+      'langcode' => $this->getLangcode($results),
+      // A flag to let hook implementations know that this is a generated item.
+      'devel_generate' => $results,
+    ]);
+
+    // Populate all non-skipped fields with sample values.
+    $this->populateFields($media, $results['skip_fields'], $results['base_fields']);
+
+    // Remove the fields which are intended to have no value.
+    foreach ($results['skip_fields'] as $field) {
+      unset($media->$field);
+    }
+
+    $media->save();
+  }
+
+  /**
+   * Determine language based on $results.
+   *
+   * @param array $results
+   *   The input values from the settings form.
+   *
+   * @return string
+   *   The language code.
+   */
+  protected function getLangcode(array $results): string {
+    if (isset($results['add_language'])) {
+      $langcodes = $results['add_language'];
+
+      return $langcodes[array_rand($langcodes)];
+    }
+
+    return $this->languageManager->getDefaultLanguage()->getId();
+  }
+
+  /**
+   * Finds out if the media item generation will run in batch process.
+   *
+   * @param int $media_items_count
+   *   Number of media items to be generated.
+   *
+   * @return bool
+   *   If the process should be a batch process.
+   */
+  protected function isBatch(int $media_items_count): bool {
+    return $media_items_count >= 50;
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/MenuDevelGenerate.php

@@ -0,0 +1,384 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\Core\Database\Connection;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Menu\MenuLinkTreeInterface;
+use Drupal\Core\Menu\MenuTreeParameters;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\menu_link_content\MenuLinkContentStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a MenuDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "menu",
+ *   label = @Translation("menus"),
+ *   description = @Translation("Generate a given number of menus and menu
+ *   links. Optionally delete current menus."), url = "menu", permission =
+ *   "administer devel_generate", settings = {
+ *     "num_menus" = 2,
+ *     "num_links" = 50,
+ *     "title_length" = 12,
+ *     "max_width" = 6,
+ *     "kill" = FALSE,
+ *   }
+ * )
+ */
+class MenuDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The menu tree service.
+   */
+  protected MenuLinkTreeInterface $menuLinkTree;
+
+  /**
+   * The menu storage.
+   */
+  protected EntityStorageInterface $menuStorage;
+
+  /**
+   * The menu link storage.
+   */
+  protected MenuLinkContentStorageInterface $menuLinkContentStorage;
+
+  /**
+   * Database connection.
+   */
+  protected Connection $database;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->menuLinkTree = $container->get('menu.link_tree');
+    $instance->menuStorage = $entity_type_manager->getStorage('menu');
+    $instance->menuLinkContentStorage = $entity_type_manager->getStorage('menu_link_content');
+    $instance->database = $container->get('database');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $menus = array_map(static fn($menu) => $menu->label(), $this->menuStorage->loadMultiple());
+    asort($menus);
+    $menus = ['__new-menu__' => $this->t('Create new menu(s)')] + $menus;
+    $form['existing_menus'] = [
+      '#type' => 'checkboxes',
+      '#title' => $this->t('Generate links for these menus'),
+      '#options' => $menus,
+      '#default_value' => ['__new-menu__'],
+      '#required' => TRUE,
+    ];
+    $form['num_menus'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Number of new menus to create'),
+      '#default_value' => $this->getSetting('num_menus'),
+      '#min' => 0,
+      '#states' => [
+        'visible' => [
+          ':input[name="existing_menus[__new-menu__]"]' => ['checked' => TRUE],
+        ],
+      ],
+    ];
+    $form['num_links'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Number of links to generate'),
+      '#default_value' => $this->getSetting('num_links'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+    $form['title_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum length for menu titles and menu links'),
+      '#description' => $this->t('Text will be generated at random lengths up to this value. Enter a number between 2 and 128.'),
+      '#default_value' => $this->getSetting('title_length'),
+      '#required' => TRUE,
+      '#min' => 2,
+      '#max' => 128,
+    ];
+    $form['link_types'] = [
+      '#type' => 'checkboxes',
+      '#title' => $this->t('Types of links to generate'),
+      '#options' => [
+        'node' => $this->t('Nodes'),
+        'front' => $this->t('Front page'),
+        'external' => $this->t('External'),
+      ],
+      '#default_value' => ['node', 'front', 'external'],
+      '#required' => TRUE,
+    ];
+    $form['max_depth'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Maximum link depth'),
+      '#options' => range(0, $this->menuLinkTree->maxDepth()),
+      '#default_value' => floor($this->menuLinkTree->maxDepth() / 2),
+      '#required' => TRUE,
+    ];
+    unset($form['max_depth']['#options'][0]);
+    $form['max_width'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum menu width'),
+      '#default_value' => $this->getSetting('max_width'),
+      '#description' => $this->t("Limit the width of the generated menu's first level of links to a certain number of items."),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Delete existing custom generated menus and menu links before generating new ones.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    // If the create new menus checkbox is off, set the number of menus to 0.
+    if (!isset($values['existing_menus']['__new-menu__']) || !$values['existing_menus']['__new-menu__']) {
+      $values['num_menus'] = 0;
+    }
+    else {
+      // Unset the aux menu to avoid attach menu new items.
+      unset($values['existing_menus']['__new-menu__']);
+    }
+
+    // Delete custom menus.
+    if ($values['kill']) {
+      [$menus_deleted, $links_deleted] = $this->deleteMenus();
+      $this->setMessage($this->t('Deleted @menus_deleted menu(s) and @links_deleted other link(s).',
+        [
+          '@menus_deleted' => $menus_deleted,
+          '@links_deleted' => $links_deleted,
+        ]));
+    }
+
+    // Generate new menus.
+    $new_menus = $this->generateMenus($values['num_menus'], $values['title_length']);
+    if ($new_menus !== []) {
+      $this->setMessage($this->formatPlural(count($new_menus), 'Created the following 1 new menu: @menus', 'Created the following @count new menus: @menus',
+        ['@menus' => implode(', ', $new_menus)]));
+    }
+
+    // Generate new menu links.
+    $menus = $new_menus;
+    if (isset($values['existing_menus'])) {
+      $menus += $values['existing_menus'];
+    }
+
+    $new_links = $this->generateLinks($values['num_links'], $menus, $values['title_length'], $values['link_types'], $values['max_depth'], $values['max_width']);
+    $this->setMessage($this->formatPlural(count($new_links), 'Created 1 new menu link.', 'Created @count new menu links.'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    $link_types = ['node', 'front', 'external'];
+    $values = [
+      'num_menus' => array_shift($args),
+      'num_links' => array_shift($args),
+      'kill' => $options['kill'],
+      'pipe' => $options['pipe'],
+      'link_types' => array_combine($link_types, $link_types),
+    ];
+
+    $max_depth = array_shift($args);
+    $max_width = array_shift($args);
+    $values['max_depth'] = $max_depth ?: 3;
+    $values['max_width'] = $max_width ?: 8;
+    $values['title_length'] = $this->getSetting('title_length');
+    $values['existing_menus']['__new-menu__'] = TRUE;
+
+    if ($this->isNumber($values['num_menus']) == FALSE) {
+      throw new \Exception(dt('Invalid number of menus'));
+    }
+
+    if ($this->isNumber($values['num_links']) == FALSE) {
+      throw new \Exception(dt('Invalid number of links'));
+    }
+
+    if ($this->isNumber($values['max_depth']) == FALSE || $values['max_depth'] > 9 || $values['max_depth'] < 1) {
+      throw new \Exception(dt('Invalid maximum link depth. Use a value between 1 and 9'));
+    }
+
+    if ($this->isNumber($values['max_width']) == FALSE || $values['max_width'] < 1) {
+      throw new \Exception(dt('Invalid maximum menu width. Use a positive numeric value.'));
+    }
+
+    return $values;
+  }
+
+  /**
+   * Deletes custom generated menus.
+   */
+  protected function deleteMenus(): array {
+    $menu_ids = [];
+    if ($this->moduleHandler->moduleExists('menu_ui')) {
+      $all = $this->menuStorage->loadMultiple();
+      foreach ($all as $menu) {
+        if (str_starts_with($menu->id(), 'devel-')) {
+          $menu_ids[] = $menu->id();
+        }
+      }
+
+      if ($menu_ids !== []) {
+        $menus = $this->menuStorage->loadMultiple($menu_ids);
+        $this->menuStorage->delete($menus);
+      }
+    }
+
+    // Delete menu links in other menus, but generated by devel.
+    $link_ids = $this->menuLinkContentStorage->getQuery()
+      ->condition('menu_name', 'devel', '<>')
+      ->condition('link__options', '%' . $this->database->escapeLike('s:5:"devel";b:1') . '%', 'LIKE')
+      ->accessCheck(FALSE)
+      ->execute();
+
+    if ($link_ids) {
+      $links = $this->menuLinkContentStorage->loadMultiple($link_ids);
+      $this->menuLinkContentStorage->delete($links);
+    }
+
+    return [count($menu_ids), count($link_ids)];
+  }
+
+  /**
+   * Generates new menus.
+   *
+   * @param int $num_menus
+   *   Number of menus to create.
+   * @param int $title_length
+   *   (optional) Maximum length of menu name.
+   *
+   * @return array
+   *   Array containing the generated menus.
+   */
+  protected function generateMenus(int $num_menus, int $title_length = 12): array {
+    $menus = [];
+
+    for ($i = 1; $i <= $num_menus; ++$i) {
+      $name = $this->randomSentenceOfLength(mt_rand(2, $title_length));
+      // Create a random string of random length for the menu id. The maximum
+      // machine-name length is 32, so allowing for prefix 'devel-' we can have
+      // up to 26 here. For safety avoid accidentally reusing the same id.
+      do {
+        $id = 'devel-' . $this->getRandom()->word(mt_rand(2, 26));
+      } while (array_key_exists($id, $menus));
+
+      $menu = $this->menuStorage->create([
+        'label' => $name,
+        'id' => $id,
+        'description' => $this->t('Description of @name', ['@name' => $name]),
+      ]);
+
+      $menu->save();
+      $menus[$menu->id()] = $menu->label();
+    }
+
+    return $menus;
+  }
+
+  /**
+   * Generates menu links in a tree structure.
+   *
+   * @return array<int|string, string>
+   *   Array containing the titles of the generated menu links.
+   */
+  protected function generateLinks(int $num_links, array $menus, int $title_length, array $link_types, int $max_depth, int $max_width): array {
+    $links = [];
+    $menus = array_keys(array_filter($menus));
+    $link_types = array_keys(array_filter($link_types));
+
+    $nids = [];
+    for ($i = 1; $i <= $num_links; ++$i) {
+      // Pick a random menu.
+      $menu_name = $menus[array_rand($menus)];
+      // Build up our link.
+      $link_title = $this->getRandom()->word(mt_rand(2, max(2, $title_length)));
+
+      /** @var \Drupal\menu_link_content\MenuLinkContentInterface $menuLinkContent */
+      $menuLinkContent = $this->menuLinkContentStorage->create([
+        'menu_name' => $menu_name,
+        'weight' => mt_rand(-50, 50),
+        'title' => $link_title,
+        'bundle' => 'menu_link_content',
+        'description' => $this->t('Description of @title.', ['@title' => $link_title]),
+      ]);
+      $link = $menuLinkContent->get('link');
+      $options['devel'] = TRUE;
+      $link->setValue(['options' => $options]);
+
+      // For the first $max_width items, make first level links, otherwise, get
+      // a random parent menu depth.
+      $max_link_depth = $i <= $max_width ? 0 : mt_rand(1, max(1, $max_depth - 1));
+
+      // Get a random parent link from the proper depth.
+      for ($depth = $max_link_depth; $depth >= 0; --$depth) {
+        $parameters = new MenuTreeParameters();
+        $parameters->setMinDepth($depth);
+        $parameters->setMaxDepth($depth);
+        $tree = $this->menuLinkTree->load($menu_name, $parameters);
+        if ($tree === []) {
+          continue;
+        }
+
+        $menuLinkContent->set('parent', array_rand($tree));
+        break;
+      }
+
+      $link_type = array_rand($link_types);
+      switch ($link_types[$link_type]) {
+        case 'node':
+          // Grab a random node ID.
+          $select = $this->database->select('node_field_data', 'n')
+            ->fields('n', ['nid', 'title'])
+            ->condition('n.status', 1)
+            ->range(0, 1)
+            ->orderRandom();
+          // Don't put a node into the menu twice.
+          if (isset($nids[$menu_name])) {
+            $select->condition('n.nid', $nids[$menu_name], 'NOT IN');
+          }
+
+          $node = $select->execute()->fetchAssoc();
+          if (isset($node['nid'])) {
+            $nids[$menu_name][] = $node['nid'];
+            $link->setValue(['uri' => 'entity:node/' . $node['nid']]);
+            $menuLinkContent->set('title', $node['title']);
+            break;
+          }
+
+        case 'external':
+          $link->setValue(['uri' => 'https://www.example.com/']);
+          break;
+
+        case 'front':
+          $link->setValue(['uri' => 'internal:/<front>']);
+          break;
+
+        default:
+          break;
+      }
+
+      $menuLinkContent->save();
+
+      $links[$menuLinkContent->id()] = $menuLinkContent->getTitle();
+    }
+
+    return $links;
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/TermDevelGenerate.php

@@ -0,0 +1,454 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\content_translation\ContentTranslationManagerInterface;
+use Drupal\Core\Database\Connection;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\taxonomy\TermInterface;
+use Drupal\taxonomy\TermStorageInterface;
+use Drupal\taxonomy\VocabularyStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a TermDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "term",
+ *   label = @Translation("terms"),
+ *   description = @Translation("Generate a given number of terms. Optionally delete current terms."),
+ *   url = "term",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 10,
+ *     "title_length" = 12,
+ *     "minimum_depth" = 1,
+ *     "maximum_depth" = 4,
+ *     "kill" = FALSE,
+ *   },
+ *   dependencies = {
+ *     "taxonomy",
+ *   },
+ * )
+ */
+class TermDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The vocabulary storage.
+   */
+  protected VocabularyStorageInterface $vocabularyStorage;
+
+  /**
+   * The term storage.
+   */
+  protected TermStorageInterface $termStorage;
+
+  /**
+   * Database connection.
+   */
+  protected Connection $database;
+
+  /**
+   * The module handler.
+   */
+  protected ModuleHandlerInterface $moduleHandler;
+
+  /**
+   * The language manager.
+   */
+  protected LanguageManagerInterface $languageManager;
+
+  /**
+   * The content translation manager.
+   */
+  protected ?ContentTranslationManagerInterface $contentTranslationManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+
+    // @phpstan-ignore ternary.alwaysTrue (False positive)
+    $content_translation_manager = $container->has('content_translation.manager') ? $container->get('content_translation.manager') : NULL;
+
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->vocabularyStorage = $entity_type_manager->getStorage('taxonomy_vocabulary');
+    $instance->termStorage = $entity_type_manager->getStorage('taxonomy_term');
+    $instance->database = $container->get('database');
+    $instance->contentTranslationManager = $content_translation_manager;
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $options = [];
+    foreach ($this->vocabularyStorage->loadMultiple() as $vocabulary) {
+      $options[$vocabulary->id()] = $vocabulary->label();
+    }
+
+    // Sort by vocabulary label.
+    asort($options);
+    // Set default to 'tags' only if it exists as a vocabulary.
+    $default_vids = array_key_exists('tags', $options) ? 'tags' : '';
+    $form['vids'] = [
+      '#type' => 'select',
+      '#multiple' => TRUE,
+      '#title' => $this->t('Vocabularies'),
+      '#required' => TRUE,
+      '#default_value' => $default_vids,
+      '#options' => $options,
+      '#description' => $this->t('Restrict terms to these vocabularies.'),
+    ];
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Number of terms'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+    $form['title_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum number of characters in term names'),
+      '#default_value' => $this->getSetting('title_length'),
+      '#required' => TRUE,
+      '#min' => 2,
+      '#max' => 255,
+    ];
+    $form['minimum_depth'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Minimum depth for new terms in the vocabulary hierarchy'),
+      '#description' => $this->t('Enter a value from 1 to 20.'),
+      '#default_value' => $this->getSetting('minimum_depth'),
+      '#min' => 1,
+      '#max' => 20,
+    ];
+    $form['maximum_depth'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum depth for new terms in the vocabulary hierarchy'),
+      '#description' => $this->t('Enter a value from 1 to 20.'),
+      '#default_value' => $this->getSetting('maximum_depth'),
+      '#min' => 1,
+      '#max' => 20,
+    ];
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Delete existing terms in specified vocabularies before generating new terms.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    // Add the language and translation options.
+    $form += $this->getLanguageForm('terms');
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    $new_terms = $this->generateTerms($values);
+    if (!empty($new_terms['terms'])) {
+      $this->setMessage($this->formatPlural($new_terms['terms'], 'Created 1 new term', 'Created @count new terms'));
+
+      // Helper function to format the number of terms and the list of terms.
+      $format_terms_func = function (array $data, $level) {
+        if ($data['total'] > 10) {
+          $data['terms'][] = '...';
+        }
+
+        return $this->formatPlural($data['total'],
+          '1 new term at level @level (@terms)',
+          '@count new terms at level @level (@terms)',
+          ['@level' => $level, '@terms' => implode(',', $data['terms'])]);
+      };
+
+      foreach ($new_terms['vocabs'] as $vid => $vlabel) {
+        if (array_key_exists($vid, $new_terms)) {
+          ksort($new_terms[$vid]);
+          $termlist = implode(', ', array_map($format_terms_func, $new_terms[$vid], array_keys($new_terms[$vid])));
+          $this->setMessage($this->t('In vocabulary @vlabel: @termlist', ['@vlabel' => $vlabel, '@termlist' => $termlist]));
+        }
+        else {
+          $this->setMessage($this->t('In vocabulary @vlabel: No terms created', ['@vlabel' => $vlabel]));
+        }
+      }
+
+    }
+
+    if ($new_terms['terms_translations'] > 0) {
+      $this->setMessage($this->formatPlural($new_terms['terms_translations'], 'Created 1 term translation', 'Created @count term translations'));
+    }
+  }
+
+  /**
+   * Deletes all terms of given vocabularies.
+   *
+   * @param array $vids
+   *   Array of vocabulary ids.
+   *
+   * @return int
+   *   The number of terms deleted.
+   */
+  protected function deleteVocabularyTerms(array $vids): int {
+    $tids = $this->vocabularyStorage->getToplevelTids($vids);
+    $terms = $this->termStorage->loadMultiple($tids);
+    $total_deleted = 0;
+    foreach ($vids as $vid) {
+      $total_deleted += count($this->termStorage->loadTree($vid));
+    }
+
+    $this->termStorage->delete($terms);
+    return $total_deleted;
+  }
+
+  /**
+   * Generates taxonomy terms for a list of given vocabularies.
+   *
+   * @param array $parameters
+   *   The input parameters from the settings form or drush command.
+   *
+   * @return array
+   *   Information about the created terms.
+   */
+  protected function generateTerms(array $parameters): array {
+    $info = [
+      'terms' => 0,
+      'terms_translations' => 0,
+    ];
+    $min_depth = $parameters['minimum_depth'];
+    $max_depth = $parameters['maximum_depth'];
+
+    // $parameters['vids'] from the UI has keys of the vocab ids. From drush
+    // the array is keyed 0,1,2. Therefore create $vocabs which has keys of the
+    // vocab ids, so it can be used with array_rand().
+    $vocabs = array_combine($parameters['vids'], $parameters['vids']);
+
+    // Delete terms from the vocabularies we are creating new terms in.
+    if ($parameters['kill']) {
+      $deleted = $this->deleteVocabularyTerms($vocabs);
+      $this->setMessage($this->formatPlural($deleted, 'Deleted 1 existing term', 'Deleted @count existing terms'));
+      if ($min_depth != 1) {
+        $this->setMessage($this->t('Minimum depth changed from @min_depth to 1 because all terms were deleted', ['@min_depth' => $min_depth]));
+        $min_depth = 1;
+      }
+    }
+
+    // Build an array of potential parents for the new terms. These will be
+    // terms in the vocabularies we are creating in, which have a depth of one
+    // less than the minimum for new terms up to one less than the maximum.
+    $all_parents = [];
+    foreach ($parameters['vids'] as $vid) {
+      $info['vocabs'][$vid] = $this->vocabularyStorage->load($vid)->label();
+      // Initialise the nested array for this vocabulary.
+      $all_parents[$vid] = ['top_level' => [], 'lower_levels' => []];
+      $ids = [];
+      for ($depth = 1; $depth < $max_depth; ++$depth) {
+        $query = $this->termStorage->getQuery()->accessCheck(FALSE)->condition('vid', $vid);
+        if ($depth == 1) {
+          // For the top level the parent id must be zero.
+          $query->condition('parent', 0);
+        }
+        else {
+          // For lower levels use the $ids array obtained in the previous loop.
+          $query->condition('parent', $ids, 'IN');
+        }
+
+        $ids = $query->execute();
+
+        if (empty($ids)) {
+          // Reached the end, no more parents to be found.
+          break;
+        }
+
+        // Store these terms as parents if they are within the depth range for
+        // new terms.
+        if ($depth == $min_depth - 1) {
+          $all_parents[$vid]['top_level'] = array_fill_keys($ids, $depth);
+        }
+        elseif ($depth >= $min_depth) {
+          $all_parents[$vid]['lower_levels'] += array_fill_keys($ids, $depth);
+        }
+      }
+
+      // No top-level parents will have been found above when the minimum depth
+      // is 1 so add a record for that data here.
+      if ($min_depth == 1) {
+        $all_parents[$vid]['top_level'] = [0 => 0];
+      }
+      elseif (empty($all_parents[$vid]['top_level'])) {
+        // No parents for required minimum level so cannot use this vocabulary.
+        unset($vocabs[$vid]);
+      }
+    }
+
+    if ($vocabs === []) {
+      // There are no available parents at the required depth in any vocabulary,
+      // so we cannot create any new terms.
+      throw new \Exception(sprintf('Invalid minimum depth %s because there are no terms in any vocabulary at depth %s', $min_depth, $min_depth - 1));
+    }
+
+    // Insert new data:
+    for ($i = 1; $i <= $parameters['num']; ++$i) {
+      // Select a vocabulary at random.
+      $vid = array_rand($vocabs);
+
+      // Set the group to use to select a random parent from. Using < 50 means
+      // on average half of the new terms will be top_level. Also if no terms
+      // exist yet in 'lower_levels' then we have to use 'top_level'.
+      $group = (mt_rand(0, 100) < 50 || empty($all_parents[$vid]['lower_levels'])) ? 'top_level' : 'lower_levels';
+      $parent = array_rand($all_parents[$vid][$group]);
+      $depth = $all_parents[$vid][$group][$parent] + 1;
+      $name = $this->getRandom()->word(mt_rand(2, $parameters['title_length']));
+
+      $values = [
+        'name' => $name,
+        'description' => 'Description of ' . $name . ' (depth ' . $depth . ')',
+        'format' => filter_fallback_format(),
+        'weight' => mt_rand(0, 10),
+        'vid' => $vid,
+        'parent' => [$parent],
+        // Give hook implementations access to the parameters used for generation.
+        'devel_generate' => $parameters,
+      ];
+      if (isset($parameters['add_language'])) {
+        $values['langcode'] = $this->getLangcode($parameters['add_language']);
+      }
+
+      /** @var \Drupal\taxonomy\TermInterface $term */
+      $term = $this->termStorage->create($values);
+
+      // Populate all fields with sample values.
+      $this->populateFields($term);
+      $term->save();
+
+      // Add translations.
+      if (isset($parameters['translate_language']) && !empty($parameters['translate_language'])) {
+        $info['terms_translations'] += $this->generateTermTranslation($parameters['translate_language'], $term);
+      }
+
+      // If the depth of the new term is less than the maximum depth then it can
+      // also be saved as a potential parent for the subsequent new terms.
+      if ($depth < $max_depth) {
+        $all_parents[$vid]['lower_levels'] += [$term->id() => $depth];
+      }
+
+      // Store data about the newly generated term.
+      ++$info['terms'];
+      @$info[$vid][$depth]['total']++;
+      // List only the first 10 new terms at each vocab/level.
+      if (!isset($info[$vid][$depth]['terms']) || count($info[$vid][$depth]['terms']) < 10) {
+        $info[$vid][$depth]['terms'][] = $term->label();
+      }
+
+      unset($term);
+    }
+
+    return $info;
+  }
+
+  /**
+   * Create translation for the given term.
+   *
+   * @param array $translate_language
+   *   Potential translate languages array.
+   * @param \Drupal\taxonomy\TermInterface $term
+   *   Term to add translations to.
+   *
+   * @return int
+   *   Number of translations added.
+   */
+  protected function generateTermTranslation(array $translate_language, TermInterface $term): int {
+    if (is_null($this->contentTranslationManager)) {
+      return 0;
+    }
+
+    if (!$this->contentTranslationManager->isEnabled('taxonomy_term', $term->bundle())) {
+      return 0;
+    }
+
+    if ($term->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_SPECIFIED
+      || $term->get('langcode')->getLangcode() === LanguageInterface::LANGCODE_NOT_APPLICABLE) {
+      return 0;
+    }
+
+    $num_translations = 0;
+    // Translate term to each target language.
+    $skip_languages = [
+      LanguageInterface::LANGCODE_NOT_SPECIFIED,
+      LanguageInterface::LANGCODE_NOT_APPLICABLE,
+      $term->get('langcode')->getLangcode(),
+    ];
+    foreach ($translate_language as $langcode) {
+      if (in_array($langcode, $skip_languages)) {
+        continue;
+      }
+
+      $translation_term = $term->addTranslation($langcode);
+      $translation_term->setName($term->getName() . ' (' . $langcode . ')');
+      $this->populateFields($translation_term);
+      $translation_term->save();
+      ++$num_translations;
+    }
+
+    return $num_translations;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    // Get default settings from the annotated command definition.
+    $defaultSettings = $this->getDefaultSettings();
+
+    $bundles = self::csvToarray($options['bundles']);
+    if (count($bundles) < 1) {
+      throw new \Exception(dt('Please provide a vocabulary machine name (--bundles).'));
+    }
+
+    foreach ($bundles as $bundle) {
+      // Verify that each bundle is a valid vocabulary id.
+      if (!$this->vocabularyStorage->load($bundle)) {
+        throw new \Exception(dt('Invalid vocabulary machine name: @name', ['@name' => $bundle]));
+      }
+    }
+
+    $number = array_shift($args) ?: $defaultSettings['num'];
+    if (!$this->isNumber($number)) {
+      throw new \Exception(dt('Invalid number of terms: @num', ['@num' => $number]));
+    }
+
+    $minimum_depth = $options['min-depth'] ?? $defaultSettings['minimum_depth'];
+    $maximum_depth = $options['max-depth'] ?? $defaultSettings['maximum_depth'];
+    if ($minimum_depth < 1 || $minimum_depth > 20 || $maximum_depth < 1 || $maximum_depth > 20 || $minimum_depth > $maximum_depth) {
+      throw new \Exception(dt('The depth values must be in the range 1 to 20 and min-depth cannot be larger than max-depth (values given: min-depth @min, max-depth @max)', ['@min' => $minimum_depth, '@max' => $maximum_depth]));
+    }
+
+    $values = [
+      'num' => $number,
+      'kill' => $options['kill'],
+      'title_length' => 12,
+      'vids' => $bundles,
+      'minimum_depth' => $minimum_depth,
+      'maximum_depth' => $maximum_depth,
+    ];
+    $add_language = self::csvToArray($options['languages']);
+    // Intersect with the enabled languages to make sure the language args
+    // passed are actually enabled.
+    $valid_languages = array_keys($this->languageManager->getLanguages(LanguageInterface::STATE_ALL));
+    $values['add_language'] = array_intersect($add_language, $valid_languages);
+
+    $translate_language = self::csvToArray($options['translations']);
+    $values['translate_language'] = array_intersect($translate_language, $valid_languages);
+    return $values;
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/UserDevelGenerate.php

@@ -0,0 +1,187 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Core\Datetime\DateFormatterInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\user\RoleStorageInterface;
+use Drupal\user\UserStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a UserDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "user",
+ *   label = @Translation("users"),
+ *   description = @Translation("Generate a given number of users. Optionally delete current users."),
+ *   url = "user",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 50,
+ *     "kill" = FALSE,
+ *     "pass" = ""
+ *   }
+ * )
+ */
+class UserDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The user storage.
+   */
+  protected UserStorageInterface $userStorage;
+
+  /**
+   * The date formatter service.
+   */
+  protected DateFormatterInterface $dateFormatter;
+
+  /**
+   * Provides system time.
+   */
+  protected TimeInterface $time;
+
+  /**
+   * The role storage.
+   */
+  protected RoleStorageInterface $roleStorage;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->userStorage = $entity_type_manager->getStorage('user');
+    $instance->dateFormatter = $container->get('date.formatter');
+    $instance->time = $container->get('datetime.time');
+    $instance->roleStorage = $entity_type_manager->getStorage('user_role');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('How many users would you like to generate?'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Delete all users (except user id 1) before generating new users.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    $roles = array_map(static fn($role): string => $role->label(), $this->roleStorage->loadMultiple());
+    unset($roles[AccountInterface::AUTHENTICATED_ROLE], $roles[AccountInterface::ANONYMOUS_ROLE]);
+    $form['roles'] = [
+      '#type' => 'checkboxes',
+      '#title' => $this->t('Which roles should the users receive?'),
+      '#description' => $this->t('Users always receive the <em>authenticated user</em> role.'),
+      '#options' => $roles,
+    ];
+
+    $form['pass'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Password to be set'),
+      '#default_value' => $this->getSetting('pass'),
+      '#size' => 32,
+      '#description' => $this->t('Leave this field empty if you do not need to set a password'),
+    ];
+
+    $options = [1 => $this->t('Now')];
+    foreach ([3600, 86400, 604800, 2592000, 31536000] as $interval) {
+      $options[$interval] = $this->dateFormatter->formatInterval($interval, 1) . ' ' . $this->t('ago');
+    }
+
+    $form['time_range'] = [
+      '#type' => 'select',
+      '#title' => $this->t('How old should user accounts be?'),
+      '#description' => $this->t('User ages will be distributed randomly from the current time, back to the selected time.'),
+      '#options' => $options,
+      '#default_value' => 604800,
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    $num = $values['num'];
+    $kill = $values['kill'];
+    $pass = $values['pass'];
+    $age = $values['time_range'];
+    $roles = array_filter($values['roles']);
+
+    if ($kill) {
+      $uids = $this->userStorage->getQuery()
+        ->condition('uid', 1, '>')
+        ->accessCheck(FALSE)
+        ->execute();
+      $users = $this->userStorage->loadMultiple($uids);
+      $this->userStorage->delete($users);
+
+      $this->setMessage($this->formatPlural(count($uids), '1 user deleted', '@count users deleted.'));
+    }
+
+    if ($num > 0) {
+      $names = [];
+      while (count($names) < $num) {
+        $name = $this->getRandom()->word(mt_rand(6, 12));
+        $names[$name] = '';
+      }
+
+      if ($roles === []) {
+        $roles = [AccountInterface::AUTHENTICATED_ROLE];
+      }
+
+      foreach (array_keys($names) as $name) {
+        /** @var \Drupal\user\UserInterface $account */
+        $account = $this->userStorage->create([
+          'uid' => NULL,
+          'name' => $name,
+          'pass' => $pass,
+          'mail' => $name . '@example.com',
+          'status' => 1,
+          'created' => $this->time->getRequestTime() - mt_rand(0, $age),
+          'roles' => array_values($roles),
+          // A flag to let hook_user_* know that this is a generated user.
+          'devel_generate' => TRUE,
+        ]);
+
+        // Populate all fields with sample values.
+        $this->populateFields($account);
+        $account->save();
+      }
+    }
+
+    $this->setMessage($this->t('@num_users created.',
+      ['@num_users' => $this->formatPlural($num, '1 user', '@count users')]));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    return [
+      'num' => array_shift($args),
+      'time_range' => 0,
+      'roles' => self::csvToArray($options['roles']),
+      'kill' => $options['kill'],
+      'pass' => $options['pass'],
+    ];
+  }
+
+}

modules/devel/devel_generate/src/Plugin/DevelGenerate/VocabularyDevelGenerate.php

@@ -0,0 +1,158 @@
+<?php
+
+namespace Drupal\devel_generate\Plugin\DevelGenerate;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Drupal\taxonomy\VocabularyStorageInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a VocabularyDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "vocabulary",
+ *   label = @Translation("vocabularies"),
+ *   description = @Translation("Generate a given number of vocabularies. Optionally delete current vocabularies."),
+ *   url = "vocabs",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 1,
+ *     "title_length" = 12,
+ *     "kill" = FALSE
+ *   },
+ *   dependencies = {
+ *     "taxonomy",
+ *   },
+ * )
+ */
+class VocabularyDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The vocabulary storage.
+   */
+  protected VocabularyStorageInterface $vocabularyStorage;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $entity_type_manager = $container->get('entity_type.manager');
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->vocabularyStorage = $entity_type_manager->getStorage('taxonomy_vocabulary');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+    $form['num'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Number of vocabularies?'),
+      '#default_value' => $this->getSetting('num'),
+      '#required' => TRUE,
+      '#min' => 0,
+    ];
+    $form['title_length'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Maximum number of characters in vocabulary names'),
+      '#default_value' => $this->getSetting('title_length'),
+      '#required' => TRUE,
+      '#min' => 2,
+      '#max' => 255,
+    ];
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Delete existing vocabularies before generating new ones.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    if ($values['kill']) {
+      $this->deleteVocabularies();
+      $this->setMessage($this->t('Deleted existing vocabularies.'));
+    }
+
+    $new_vocs = $this->generateVocabularies($values['num'], $values['title_length']);
+    if ($new_vocs !== []) {
+      $this->setMessage($this->t('Created the following new vocabularies: @vocs', ['@vocs' => implode(', ', $new_vocs)]));
+    }
+  }
+
+  /**
+   * Deletes all vocabularies.
+   */
+  protected function deleteVocabularies(): void {
+    $vocabularies = $this->vocabularyStorage->loadMultiple();
+    $this->vocabularyStorage->delete($vocabularies);
+  }
+
+  /**
+   * Generates vocabularies.
+   *
+   * @param int $records
+   *   Number of vocabularies to create.
+   * @param int $maxlength
+   *   (optional) Maximum length for vocabulary name.
+   *
+   * @return array
+   *   Array containing the generated vocabularies id.
+   */
+  protected function generateVocabularies(int $records, int $maxlength = 12): array {
+    $vocabularies = [];
+
+    // Insert new data:
+    for ($i = 1; $i <= $records; ++$i) {
+      $name = $this->getRandom()->word(mt_rand(2, $maxlength));
+
+      $vocabulary = $this->vocabularyStorage->create([
+        'name' => $name,
+        'vid' => mb_strtolower($name),
+        'langcode' => LanguageInterface::LANGCODE_NOT_SPECIFIED,
+        'description' => 'Description of ' . $name,
+        'hierarchy' => 1,
+        'weight' => mt_rand(0, 10),
+        'multiple' => 1,
+        'required' => 0,
+        'relations' => 1,
+      ]);
+
+      // Populate all fields with sample values.
+      $this->populateFields($vocabulary);
+      $vocabulary->save();
+
+      $vocabularies[] = $vocabulary->id();
+      unset($vocabulary);
+    }
+
+    return $vocabularies;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    $values = [
+      'num' => array_shift($args),
+      'kill' => $options['kill'],
+      'title_length' => 12,
+    ];
+
+    if ($this->isNumber($values['num']) == FALSE) {
+      throw new \Exception(dt('Invalid number of vocabularies: @num.', ['@num' => $values['num']]));
+    }
+
+    return $values;
+  }
+
+}

modules/devel/devel_generate/src/Routing/DevelGenerateRoutes.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Drupal\devel_generate\Routing;
+
+use Drupal\Component\Plugin\PluginManagerInterface;
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\devel_generate\Form\DevelGenerateForm;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\Routing\Route;
+
+/**
+ * Provides dynamic routes for devel_generate.
+ */
+class DevelGenerateRoutes implements ContainerInjectionInterface {
+
+  /**
+   * The manager to be used for instantiating plugins.
+   */
+  protected PluginManagerInterface $develGenerateManager;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container): self {
+    $instance = new self();
+    $instance->develGenerateManager = $container->get('plugin.manager.develgenerate');
+
+    return $instance;
+  }
+
+  /**
+   * Define routes for all devel_generate plugins.
+   */
+  public function routes(): array {
+    $devel_generate_plugins = $this->develGenerateManager->getDefinitions();
+
+    $routes = [];
+    foreach ($devel_generate_plugins as $id => $plugin) {
+      $label = $plugin['label'];
+      $type_url_str = str_replace('_', '-', $plugin['url']);
+      $routes['devel_generate.' . $id] = new Route(
+        'admin/config/development/generate/' . $type_url_str,
+        [
+          '_form' => DevelGenerateForm::class,
+          '_title' => 'Generate ' . $label,
+          '_plugin_id' => $id,
+        ],
+        [
+          '_permission' => $plugin['permission'],
+        ]
+      );
+    }
+
+    // Add the route for the 'Generate' admin group on the admin/config page.
+    // This also provides the page for all devel_generate links.
+    $routes['devel_generate.admin_config_generate'] = new Route(
+      '/admin/config/development/generate',
+      [
+        '_controller' => '\Drupal\system\Controller\SystemController::systemAdminMenuBlockPage',
+        '_title' => 'Generate',
+      ],
+      [
+        '_permission' => 'administer devel_generate',
+      ]
+    );
+
+    return $routes;
+  }
+
+}

modules/devel/devel_generate/tests/modules/devel_generate_example/devel_generate_example.info.yml

@@ -0,0 +1,12 @@
+name: 'Devel Generate Example'
+type: module
+description: 'Create an example of a Devel Generate plugin type for testing purposes.'
+package: Testing
+configure: admin/config/development/generate
+tags:
+  - developer
+
+# Information added by Drupal.org packaging script on 2024-06-26
+version: '5.2.1+50-dev'
+project: 'devel'
+datestamp: 1719414589

modules/devel/devel_generate/tests/modules/devel_generate_example/src/Plugin/DevelGenerate/ExampleDevelGenerate.php

@@ -0,0 +1,114 @@
+<?php
+
+namespace Drupal\devel_generate_example\Plugin\DevelGenerate;
+
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\devel_generate\DevelGenerateBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides a ExampleDevelGenerate plugin.
+ *
+ * @DevelGenerate(
+ *   id = "devel_generate_example",
+ *   label = "Example",
+ *   description = "Generate a given number of examples.",
+ *   url = "devel_generate_example",
+ *   permission = "administer devel_generate",
+ *   settings = {
+ *     "num" = 50,
+ *     "kill" = FALSE
+ *   }
+ * )
+ */
+class ExampleDevelGenerate extends DevelGenerateBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * Provides system time.
+   */
+  protected TimeInterface $time;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
+    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
+    $instance->time = $container->get('datetime.time');
+
+    return $instance;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state): array {
+
+    $form['num'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('How many examples would you like to generate?'),
+      '#default_value' => $this->getSetting('num'),
+      '#size' => 10,
+    ];
+
+    $form['kill'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Delete all examples before generating new examples.'),
+      '#default_value' => $this->getSetting('kill'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function generateElements(array $values): void {
+    $num = $values['num'];
+    $kill = $values['kill'];
+
+    if ($kill) {
+      $this->setMessage($this->t('Old examples have been deleted.'));
+    }
+
+    // Creating user in order to demonstrate
+    // how to override default business login generation.
+    $edit = [
+      'uid'     => NULL,
+      'name'    => 'example_devel_generate',
+      'pass'    => '',
+      'mail'    => 'example_devel_generate@example.com',
+      'status'  => 1,
+      'created' => $this->time->getRequestTime(),
+      'roles' => '',
+      // A flag to let hook_user_* know that this is a generated user.
+      'devel_generate' => TRUE,
+    ];
+
+    $account = user_load_by_name('example_devel_generate');
+    if (!$account) {
+      $account = $this->entityTypeManager->getStorage('user')->create($edit);
+    }
+
+    // Populate all fields with sample values.
+    $this->populateFields($account);
+
+    $account->save();
+
+    $this->setMessage($this->t('@num_examples created.', [
+      '@num_examples' => $this->formatPlural($num, '1 example', '@count examples'),
+    ]));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateDrushParams(array $args, array $options = []): array {
+    return [
+      'num' => $options['num'],
+      'kill' => $options['kill'],
+    ];
+  }
+
+}

modules/devel/devel_generate/tests/modules/devel_generate_fields/devel_generate_fields.info.yml

@@ -0,0 +1,11 @@
+name: 'Devel Generate Fields'
+type: module
+description: 'Alter in a base field for testing purposes.'
+package: Testing
+tags:
+  - developer
+
+# Information added by Drupal.org packaging script on 2024-06-26
+version: '5.2.1+50-dev'
+project: 'devel'
+datestamp: 1719414589

modules/devel/devel_generate/tests/modules/devel_generate_fields/devel_generate_fields.module

@@ -0,0 +1,21 @@
+<?php
+
+/**
+ * @file
+ * Test module for field population.
+ */
+
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+/**
+ * Implements hook_entity_base_field_info_alter().
+ */
+function devel_generate_fields_entity_base_field_info_alter(array &$fields, EntityTypeInterface $entity_type): void {
+  if (in_array($entity_type->id(), ['node', 'media'])) {
+    $fields['phish'] = BaseFieldDefinition::create('string')
+      ->setName('phish')
+      ->setLabel(new TranslatableMarkup('Phish music'));
+  }
+}

modules/devel/devel_generate/tests/src/Functional/DevelGenerateBrowserTest.php

@@ -0,0 +1,439 @@
+<?php
+
+namespace Drupal\Tests\devel_generate\Functional;
+
+use Drupal\media\Entity\Media;
+use Drupal\node\Entity\Node;
+use Drupal\taxonomy\Entity\Term;
+use Drupal\Tests\media\Traits\MediaTypeCreationTrait;
+
+/**
+ * Tests the logic to generate data.
+ *
+ * @group devel_generate
+ */
+class DevelGenerateBrowserTest extends DevelGenerateBrowserTestBase {
+
+  use MediaTypeCreationTrait;
+
+  /**
+   * Tests generating users.
+   */
+  public function testDevelGenerateUsers(): void {
+    $this->drupalGet('admin/config/development/generate/user');
+    $edit = [
+      'num' => 4,
+    ];
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('4 users created.');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+
+  }
+
+  /**
+   * Tests that if no content types are selected an error message is shown.
+   */
+  public function testDevelGenerateContent(): void {
+    $this->drupalGet('admin/config/development/generate/content');
+    $edit = [
+      'num' => 4,
+      'title_length' => 4,
+    ];
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Please select at least one content type');
+
+    // Create a node in order to test the Delete content checkbox.
+    $this->drupalCreateNode(['type' => 'article']);
+
+    // Generate articles with comments and aliases.
+    $this->drupalGet('admin/config/development/generate/content');
+    $edit = [
+      'num' => 4,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'time_range' => 604800,
+      'max_comments' => 3,
+      'title_length' => 4,
+      'add_alias' => 1,
+    ];
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Deleted 1 node');
+    $this->assertSession()->pageTextContains('Created 4 nodes');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+    $this->assertSession()->pageTextNotContains('translations');
+
+    // Tests that nodes have been created in the generation process.
+    $nodes = Node::loadMultiple();
+    $this->assertEquals(4, count($nodes), 'Nodes generated successfully.');
+
+    // Tests url alias for the generated nodes.
+    foreach ($nodes as $node) {
+      $alias = 'node-' . $node->id() . '-' . $node->bundle();
+      $this->drupalGet($alias);
+      $this->assertSession()->statusCodeEquals(200);
+      $this->assertSession()->pageTextContains($node->getTitle());
+    }
+
+    // Generate articles with translations.
+    $this->drupalGet('admin/config/development/generate/content');
+    $edit = [
+      'num' => 3,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'add_language[]' => ['en'],
+      'translate_language[]' => ['de', 'ca'],
+      'add_alias' => TRUE,
+    ];
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Deleted 4 nodes');
+    $this->assertSession()->pageTextContains('Created 3 nodes');
+    // Two translations for each node makes six.
+    $this->assertSession()->pageTextContains('Created 6 node translations');
+    $articles = \Drupal::entityQuery('node')->accessCheck(FALSE)->execute();
+    $this->assertCount(3, $articles);
+    $node = Node::load(end($articles));
+    $this->assertTrue($node->hasTranslation('de'));
+    $this->assertTrue($node->hasTranslation('ca'));
+    $this->assertFalse($node->hasTranslation('fr'));
+
+    // Check url alias for each of the translations.
+    foreach (Node::loadMultiple($articles) as $node) {
+      foreach (['de', 'ca'] as $langcode) {
+        $translation_node = $node->getTranslation($langcode);
+        $alias = 'node-' . $translation_node->id() . '-' . $translation_node->bundle() . '-' . $langcode;
+        $this->drupalGet($langcode . '/' . $alias);
+        $this->assertSession()->statusCodeEquals(200);
+        $this->assertSession()->pageTextContains($translation_node->getTitle());
+      }
+    }
+
+    // Create article to make sure it is not deleted when only killing pages.
+    $article = $this->drupalCreateNode(['type' => 'article', 'title' => 'Alive']);
+    // The 'page' content type is not enabled for translation.
+    $edit = [
+      'num' => 2,
+      'kill' => TRUE,
+      'node_types[page]' => TRUE,
+      'add_language[]' => ['en'],
+      'translate_language[]' => ['fr'],
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextNotContains('Deleted');
+    $this->assertSession()->pageTextContains('Created 2 nodes');
+    $this->assertSession()->pageTextNotContains('node translations');
+    // Check that 'kill' has not deleted the article.
+    $this->assertNotEmpty(Node::load($article->id()));
+    $pages = \Drupal::entityQuery('node')->condition('type', 'page')->accessCheck(FALSE)->execute();
+    $this->assertCount(2, $pages);
+    $node = Node::load(end($pages));
+    $this->assertFalse($node->hasTranslation('fr'));
+
+    // Create articles with add-type-label option.
+    $edit = [
+      'num' => 5,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'add_type_label' => TRUE,
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created 5 nodes');
+    $this->assertSession()->pageTextContains('Generate process complete');
+
+    // Count the articles created in the generation process.
+    $nodes = \Drupal::entityQuery('node')->accessCheck(FALSE)->condition('type', 'article')->execute();
+    $this->assertCount(5, $nodes);
+
+    // Load the final node and verify that the title starts with the label.
+    $node = Node::load(end($nodes));
+    $this->assertEquals('Article - ', substr($node->title->value, 0, 10));
+
+    // Test creating content with specified authors. First create 15 more users
+    // making 18 in total, to make the test much stronger.
+    for ($i = 0; $i < 15; ++$i) {
+      $this->drupalCreateUser();
+    }
+
+    $edit = [
+      'num' => 10,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'authors[3]' => TRUE,
+      'authors[4]' => TRUE,
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+
+    // Display the full content list for information and debug only.
+    $this->drupalGet('admin/content');
+
+    // Count all the articles by user 3 and 4 and by others. We count the two
+    // users nodes separately to ensure that there are some by each user.
+    $nodes_by_user_3 = \Drupal::entityQuery('node')->accessCheck(FALSE)->condition('type', 'article')->condition('uid', ['3'], 'IN')->execute();
+    $nodes_by_user_4 = \Drupal::entityQuery('node')->accessCheck(FALSE)->condition('type', 'article')->condition('uid', ['4'], 'IN')->execute();
+    $nodes_by_others = \Drupal::entityQuery('node')->accessCheck(FALSE)->condition('type', 'article')->condition('uid', ['3', '4'], 'NOT IN')->execute();
+
+    // If the user option was not working correctly and users were assigned at
+    // random, then the chance that these assertions will correctly detect the
+    // error is 1 - (2/18 ** 10) = 99.99%.
+    $this->assertEquals(10, count($nodes_by_user_3) + count($nodes_by_user_4));
+    $this->assertCount(0, $nodes_by_others);
+
+    // If the user option is coded correctly the chance of either of these
+    // assertions giving a false failure is 1/2 ** 10 = 0.097%.
+    $this->assertGreaterThan(0, count($nodes_by_user_3));
+    $this->assertGreaterThan(0, count($nodes_by_user_4));
+  }
+
+  /**
+   * Tests generating terms.
+   */
+  public function testDevelGenerateTerms(): void {
+    // Generate terms.
+    $edit = [
+      'vids[]' => $this->vocabulary->id(),
+      'num' => 5,
+      'title_length' => 12,
+    ];
+    $this->drupalGet('admin/config/development/generate/term');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created 5 new terms');
+    $this->assertSession()->pageTextContains('In vocabulary ' . $this->vocabulary->label());
+    $this->assertSession()->pageTextNotContains('translations');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+    $this->assertCount(5, \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->execute());
+
+    // Generate terms with translations.
+    $edit = [
+      'vids[]' => $this->vocabulary->id(),
+      'num' => 3,
+      'add_language[]' => ['en'],
+      'translate_language[]' => ['ca'],
+    ];
+    $this->drupalGet('admin/config/development/generate/term');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextNotContains('Deleted');
+    $this->assertSession()->pageTextContains('Created 3 new terms');
+    $this->assertSession()->pageTextContains('Created 3 term translations');
+    // Not using 'kill' so there should be 8 terms.
+    $terms = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->execute();
+    $this->assertCount(8, $terms);
+    // Check the translations created (and not created).
+    $term = Term::load(end($terms));
+    $this->assertTrue($term->hasTranslation('ca'));
+    $this->assertFalse($term->hasTranslation('de'));
+    $this->assertFalse($term->hasTranslation('fr'));
+
+    // Generate terms in vocabulary 2 only.
+    $edit = [
+      'vids[]' => $this->vocabulary2->id(),
+      'num' => 4,
+    ];
+    $this->drupalGet('admin/config/development/generate/term');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created 4 new terms');
+    $this->assertSession()->pageTextNotContains('In vocabulary ' . $this->vocabulary->label());
+    $this->assertSession()->pageTextContains('In vocabulary ' . $this->vocabulary2->label());
+    // Check the term count in each vocabulary.
+    $terms1 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary->id())->execute();
+    $this->assertCount(8, $terms1);
+    $terms2 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary2->id())->execute();
+    $this->assertCount(4, $terms2);
+
+    // Generate in vocabulary 2 with 'kill' to remove the existing vocab2 terms.
+    $edit = [
+      'vids[]' => $this->vocabulary2->id(),
+      'num' => 6,
+      'kill' => TRUE,
+    ];
+    $this->drupalGet('admin/config/development/generate/term');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Deleted 4 existing terms');
+    $this->assertSession()->pageTextContains('Created 6 new terms');
+    // Check the term count in vocabulary 1 has not changed.
+    $terms1 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary->id())->execute();
+    $this->assertCount(8, $terms1);
+    // Check the term count in vocabulary 2 is just from the second call.
+    $terms2 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary2->id())->execute();
+    $this->assertCount(6, $terms2);
+
+    // Generate in both vocabularies and specify minimum and maximum depth.
+    $edit = [
+      'vids[]' => [$this->vocabulary->id(), $this->vocabulary2->id()],
+      'num' => 9,
+      'minimum_depth' => 2,
+      'maximum_depth' => 6,
+    ];
+    $this->drupalGet('admin/config/development/generate/term');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created 9 new terms');
+    // Check the total term count is 8 + 6 + 9 = 23.
+    $terms1 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary->id())->execute();
+    $terms2 = \Drupal::entityQuery('taxonomy_term')->accessCheck(FALSE)->condition('vid', $this->vocabulary2->id())->execute();
+    $this->assertCount(23, $terms1 + $terms2);
+
+  }
+
+  /**
+   * Tests generating vocabularies.
+   */
+  public function testDevelGenerateVocabs(): void {
+    $edit = [
+      'num' => 5,
+      'title_length' => 12,
+      'kill' => TRUE,
+    ];
+    $this->drupalGet('admin/config/development/generate/vocabs');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created the following new vocabularies: ');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+  }
+
+  /**
+   * Tests generating menus.
+   *
+   * @todo Add test coverage to check:
+   *   - title_length is not exceeded.
+   *   - max_depth and max_width work as designed.
+   *   - generating links in existing menus, and then deleting them with kill.
+   *   - using specific link_types settings only create those links.
+   */
+  public function testDevelGenerateMenus(): void {
+    $edit = [
+      'num_menus' => 5,
+      'num_links' => 7,
+    ];
+    $this->drupalGet('admin/config/development/generate/menu');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Created the following 5 new menus: ');
+    $this->assertSession()->pageTextContains('Created 7 new menu links');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+
+    // Use big numbers for menus and links, but short text, to test for clashes.
+    // Also verify the kill option.
+    $edit = [
+      'num_menus' => 160,
+      'num_links' => 380,
+      'title_length' => 3,
+      'kill' => 1,
+    ];
+    $this->drupalGet('admin/config/development/generate/menu');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Deleted 5 menu(s) and 0 other link(s).');
+    $this->assertSession()->pageTextContains('Created the following 160 new menus: ');
+    $this->assertSession()->pageTextContains('Created 380 new menu links');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+  }
+
+  /**
+   * Tests generating media.
+   */
+  public function testDevelGenerateMedia(): void {
+    // As the 'media' plugin has a dependency on 'media' module, the plugin is
+    // not generating a route to the plugin form.
+    $this->drupalGet('admin/config/development/generate/media');
+    $this->assertSession()->statusCodeEquals(404);
+    // Enable the module and retry.
+    \Drupal::service('module_installer')->install(['media']);
+    $this->getSession()->reload();
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('Generate media');
+
+    // Create two media types.
+    $media_type1 = $this->createMediaType('image');
+    $media_type2 = $this->createMediaType('audio_file');
+
+    // Creating media items (non-batch mode).
+    $edit = [
+      'num' => 5,
+      'name_length' => 12,
+      sprintf('media_types[%s]', $media_type1->id()) => 1,
+      sprintf('media_types[%s]', $media_type2->id()) => 1,
+      'base_fields' => 'phish',
+      'kill' => 1,
+    ];
+    $this->drupalGet('admin/config/development/generate/media');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Finished creating 5 media items.');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+    $medias = \Drupal::entityQuery('media')->accessCheck(FALSE)->execute();
+    $this->assertCount(5, $medias);
+    $media = Media::load(end($medias));
+    $this->assertNotEmpty($media->get('phish')->getString());
+
+    // Creating media items (batch mode).
+    $edit = [
+      'num' => 56,
+      'name_length' => 6,
+      sprintf('media_types[%s]', $media_type1->id()) => 1,
+      sprintf('media_types[%s]', $media_type2->id()) => 1,
+      'base_fields' => 'phish',
+      'kill' => 1,
+    ];
+    $this->drupalGet('admin/config/development/generate/media');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Finished 56 elements created successfully.');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+    $this->assertCount(56, \Drupal::entityQuery('media')->accessCheck(FALSE)->execute());
+  }
+
+  /**
+   * Tests generating content in batch mode.
+   */
+  public function testDevelGenerateBatchContent(): void {
+    // For 50 or more nodes, the processing will be done via batch.
+    $edit = [
+      'num' => 55,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'node_types[page]' => TRUE,
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+    $this->assertSession()->pageTextContains('Finished 55 elements created successfully.');
+    $this->assertSession()->pageTextContains('Generate process complete.');
+
+    // Tests that the expected number of nodes have been created.
+    $count = count(Node::loadMultiple());
+    $this->assertEquals(55, $count, sprintf('The expected total number of nodes is %s, found %s', 55, $count));
+
+    // Create nodes with translations via batch.
+    $edit = [
+      'num' => 52,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'node_types[page]' => TRUE,
+      'add_language[]' => ['en'],
+      'translate_language[]' => ['de', 'ca'],
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+    $this->assertCount(52, \Drupal::entityQuery('node')->accessCheck(FALSE)->execute());
+    // Only articles will have translations so get that number.
+    $articles = \Drupal::entityQuery('node')->accessCheck(FALSE)->condition('type', 'article')->execute();
+    $this->assertSession()->pageTextContains(sprintf('Finished 52 elements and %s translations created successfully.', 2 * count($articles)));
+
+    // Generate only articles.
+    $edit = [
+      'num' => 60,
+      'kill' => TRUE,
+      'node_types[article]' => TRUE,
+      'node_types[page]' => FALSE,
+    ];
+    $this->drupalGet('admin/config/development/generate/content');
+    $this->submitForm($edit, 'Generate');
+
+    // Tests that all the created nodes were of the node type selected.
+    $nodeStorage = $this->container->get('entity_type.manager')->getStorage('node');
+    $type = 'article';
+    $count = $nodeStorage->getQuery()
+      ->condition('type', $type)
+      ->accessCheck(FALSE)
+      ->count()
+      ->execute();
+    $this->assertEquals(60, $count, sprintf('The expected number of %s is %s, found %s', $type, 60, $count));
+
+  }
+
+}

modules/devel/devel_generate/tests/src/Functional/DevelGenerateBrowserTestBase.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Drupal\Tests\devel_generate\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\devel_generate\Traits\DevelGenerateSetupTrait;
+
+/**
+ * Base class for devel_generate functional browser tests.
+ *
+ * DevelGenerateCommandsTest should not extend this class so that it can remain
+ * independent and be used as a cut-and-paste example for other developers.
+ */
+abstract class DevelGenerateBrowserTestBase extends BrowserTestBase {
+
+  use DevelGenerateSetupTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var string[]
+   */
+  protected static $modules = [
+    'content_translation',
+    'devel',
+    'devel_generate',
+    'devel_generate_fields',
+    'language',
+    'menu_ui',
+    'node',
+    'comment',
+    'taxonomy',
+    'path',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Prepares the testing environment.
+   */
+  public function setUp(): void {
+    parent::setUp();
+    $this->setUpData();
+  }
+
+}

modules/devel/devel_generate/tests/src/Functional/DevelGenerateCommandsTest.php

@@ -0,0 +1,320 @@
+<?php
+
+namespace Drupal\Tests\devel_generate\Functional;
+
+use Drupal\comment\Entity\Comment;
+use Drupal\devel_generate\Drush\Commands\DevelGenerateCommands;
+use Drupal\media\Entity\Media;
+use Drupal\menu_link_content\Entity\MenuLinkContent;
+use Drupal\node\Entity\Node;
+use Drupal\system\Entity\Menu;
+use Drupal\taxonomy\Entity\Term;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\devel_generate\Traits\DevelGenerateSetupTrait;
+use Drupal\Tests\media\Traits\MediaTypeCreationTrait;
+use Drupal\user\Entity\User;
+use Drush\TestTraits\DrushTestTrait;
+
+/**
+ * Test class for the Devel Generate drush commands.
+ *
+ * Note: Drush must be in the Composer project.
+ *
+ * @coversDefaultClass \Drupal\devel_generate\Drush\Commands\DevelGenerateCommands
+ * @group devel_generate
+ */
+class DevelGenerateCommandsTest extends BrowserTestBase {
+
+  use DrushTestTrait;
+  use DevelGenerateSetupTrait;
+  use MediaTypeCreationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'comment',
+    'content_translation',
+    'devel',
+    'devel_generate',
+    'devel_generate_fields',
+    'language',
+    'media',
+    'menu_ui',
+    'node',
+    'path',
+    'taxonomy',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Prepares the testing environment.
+   */
+  public function setUp(): void {
+    parent::setUp();
+    $this->setUpData();
+  }
+
+  /**
+   * Tests generating users.
+   */
+  public function testDrushGenerateUsers(): void {
+    // Make sure users get created, and with correct roles.
+    $this->drush(DevelGenerateCommands::USERS, ['55'], [
+      'kill' => NULL,
+      'roles' => 'administrator',
+    ]);
+    $user = User::load(55);
+    $this->assertTrue($user->hasRole('administrator'));
+  }
+
+  /**
+   * Tests generating terms.
+   */
+  public function testDrushGenerateTerms(): void {
+    // Make sure terms get created, and with correct vocab.
+    $this->drush(DevelGenerateCommands::TERMS, ['55'], [
+      'kill' => NULL,
+      'bundles' => $this->vocabulary->id(),
+    ]);
+    $term = Term::load(55);
+    $this->assertEquals($this->vocabulary->id(), $term->bundle());
+
+    // Make sure terms get created, with proper language.
+    $this->drush(DevelGenerateCommands::TERMS, ['10'], [
+      'kill' => NULL,
+      'bundles' => $this->vocabulary->id(),
+      'languages' => 'fr',
+    ]);
+    $term = Term::load(60);
+    $this->assertEquals('fr', $term->language()->getId());
+
+    // Make sure terms gets created, with proper translation.
+    $this->drush(DevelGenerateCommands::TERMS, ['10'], [
+      'kill' => NULL,
+      'bundles' => $this->vocabulary->id(),
+      'languages' => 'fr',
+      'translations' => 'de',
+    ]);
+    $term = Term::load(70);
+    $this->assertTrue($term->hasTranslation('de'));
+    $this->assertTrue($term->hasTranslation('fr'));
+  }
+
+  /**
+   * Tests generating vocabularies.
+   */
+  public function testDrushGenerateVocabs(): void {
+    // Make sure vocabs get created.
+    $this->drush(DevelGenerateCommands::VOCABS, ['5'], ['kill' => NULL]);
+    $vocabs = Vocabulary::loadMultiple();
+    $this->assertGreaterThan(4, count($vocabs));
+    $vocab = array_pop($vocabs);
+    $this->assertNotEmpty($vocab);
+  }
+
+  /**
+   * Tests generating menus.
+   */
+  public function testDrushGenerateMenus(): void {
+    $generatedMenu = NULL;
+
+    // Make sure menus, and with correct properties.
+    $this->drush(DevelGenerateCommands::MENUS, ['1', '5'], ['kill' => NULL]);
+    $menus = Menu::loadMultiple();
+    foreach ($menus as $menu) {
+      if (str_contains($menu->id(), 'devel-')) {
+        // We have a menu that we created.
+        $generatedMenu = $menu;
+        break;
+      }
+    }
+
+    $link = MenuLinkContent::load(5);
+
+    $this->assertNotNull($generatedMenu, 'Generated menu successfully.');
+    $this->assertNotNull($link, 'Generated link successfully.');
+    $this->assertEquals($generatedMenu->id(), $link->getMenuName(), 'Generated menu ID matches link menu name.');
+  }
+
+  /**
+   * Tests generating content.
+   */
+  public function testDrushGenerateContent(): void {
+    // Generate content using the minimum parameters.
+    $this->drush(DevelGenerateCommands::CONTENT, ['21']);
+    $node = Node::load(21);
+    $this->assertNotEmpty($node);
+
+    // Make sure articles get comments. Only one third of articles will have
+    // comment status 'open' and therefore the ability to receive a comment.
+    // However, generating 30 articles will give the likelihood of test failure
+    // (i.e. no article gets a comment) as 2/3 ^ 30 = 0.00052% or 1 in 191751.
+    $this->drush(DevelGenerateCommands::CONTENT, ['30', '9'], [
+      'kill' => NULL,
+      'bundles' => 'article',
+    ]);
+    $comment = Comment::load(1);
+    $this->assertNotEmpty($comment);
+
+    // Generate content with a higher number that triggers batch running.
+    $this->drush(DevelGenerateCommands::CONTENT, ['55'], ['kill' => NULL]);
+    $nodes = \Drupal::entityQuery('node')->accessCheck(FALSE)->execute();
+    $this->assertCount(55, $nodes);
+    $messages = $this->getErrorOutput();
+    $this->assertStringContainsStringIgnoringCase('Finished 55 elements created successfully.', $messages, 'devel-generate-content batch ending message not found');
+
+    // Generate specified language. Verify base field is populated.
+    $this->drush(DevelGenerateCommands::CONTENT, ['10'], [
+      'kill' => NULL,
+      'languages' => 'fr',
+      'base-fields' => 'phish',
+    ]);
+    $nodes = \Drupal::entityQuery('node')->accessCheck(FALSE)->execute();
+    $node = Node::load(end($nodes));
+    $this->assertEquals('fr', $node->language()->getId());
+    $this->assertNotEmpty($node->get('phish')->getString());
+
+    // Generate content with translations.
+    $this->drush(DevelGenerateCommands::CONTENT, ['18'], [
+      'kill' => NULL,
+      'languages' => 'fr',
+      'translations' => 'de',
+    ]);
+    // Only articles are enabled for translations.
+    $articles = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'article')
+      ->execute();
+    $pages = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'page')
+      ->execute();
+    $this->assertCount(18, $articles + $pages);
+    // Check that the last article has 'de' and 'fr' but no 'ca' translation.
+    $node = Node::load(end($articles));
+    $this->assertTrue($node->hasTranslation('de'));
+    $this->assertTrue($node->hasTranslation('fr'));
+    $this->assertFalse($node->hasTranslation('ca'));
+
+    // Generate just page content with option --add-type-label.
+    // Note: Use the -v verbose option to get the ending message shown when not
+    // generating enough to trigger batch mode.
+    // @todo Remove -v when the messages are shown for both run types.
+    $this->drush(DevelGenerateCommands::CONTENT . ' -v', ['9'], [
+      'kill' => NULL,
+      'bundles' => 'page',
+      'add-type-label' => NULL,
+    ]);
+    // Count the page nodes.
+    $nodes = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'page')
+      ->execute();
+    $this->assertCount(9, $nodes);
+    $messages = $this->getErrorOutput();
+    $this->assertStringContainsStringIgnoringCase('Created 9 nodes', $messages, 'batch end message not found');
+    // Load the final node and verify that the title starts with the label.
+    $node = Node::load(end($nodes));
+    $this->assertEquals('Basic Page - ', substr($node->title->value, 0, 13));
+
+    // Generate articles with a specified users.
+    $this->drush(DevelGenerateCommands::CONTENT . ' -v', ['10'], [
+      'kill' => NULL,
+      'bundles' => 'article',
+      'authors' => '2',
+    ]);
+    // Count the nodes assigned to user 2. We have two other users (0 and 1) so
+    // if the code was broken and users were assigned randomly the chance that
+    // this fauly would be detected is 1 - (1/3 ** 10) = 99.998%.
+    $nodes = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'article')
+      ->condition('uid', ['2'], 'IN')
+      ->execute();
+    $this->assertCount(10, $nodes);
+
+    // Generate page content using the 'roles' option to select authors based
+    // on the roles that the user has. For this we need a new user with a
+    // distinct role.
+    $userA = $this->drupalCreateUser(['access content']);
+    $roleA = $userA->getRoles()[1];
+    $this->drush(DevelGenerateCommands::CONTENT . ' -v', ['8'], [
+      'kill' => NULL,
+      'bundles' => 'page',
+      'roles' => $roleA,
+    ]);
+    // Count the number of nodes assigned to User A. There are three other users
+    // so if the code was broken and authors assigned randomly, the chance that
+    // this test would detect the fault is 1 - (1/4 ^ 8) = 99.998%.
+    $nodesA = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'page')
+      ->condition('uid', $userA->id())
+      ->execute();
+    $this->assertCount(8, $nodesA, 'User A should have all the generated content');
+
+    // Repeat the above using two roles and two users.
+    $userB = $this->drupalCreateUser(['create page content']);
+    $roleB = $userB->getRoles()[1];
+    $this->drush(DevelGenerateCommands::CONTENT . ' -v', ['20'], [
+      'kill' => NULL,
+      'bundles' => 'page',
+      'roles' => sprintf('%s, %s', $roleA, $roleB),
+    ]);
+    // Count the nodes assigned to users A and B.  There are three other users
+    // so if the code was broken and users were assigned randomly the chance
+    // that the test would detect the fault is 1 - (2/5 ^ 20) = 99.999%.
+    $nodesA = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'page')
+      ->condition('uid', $userA->id())
+      ->execute();
+    $nodesB = \Drupal::entityQuery('node')
+      ->accessCheck(FALSE)
+      ->condition('type', 'page')
+      ->condition('uid', $userB->id())
+      ->execute();
+    $this->assertGreaterThan(0, count($nodesA), 'User A should have some content');
+    $this->assertGreaterThan(0, count($nodesB), 'User B should have some content');
+    $this->assertCount(20, $nodesA + $nodesB);
+  }
+
+  /**
+   * Tests generating media.
+   */
+  public function testDrushGenerateMedia(): void {
+    // Create two media types.
+    $media_type1 = $this->createMediaType('image');
+    $media_type2 = $this->createMediaType('audio_file');
+    // Make sure media items gets created with batch process.
+    $this->drush(DevelGenerateCommands::MEDIA, ['53'], [
+      'kill' => NULL,
+      'base-fields' => 'phish',
+    ]);
+    $this->assertCount(53, \Drupal::entityQuery('media')
+      ->accessCheck(FALSE)
+      ->execute());
+    $messages = $this->getErrorOutput();
+    $this->assertStringContainsStringIgnoringCase('Finished 53 elements created successfully.', $messages, 'devel-generate-media batch ending message not found');
+    $medias = \Drupal::entityQuery('media')->accessCheck(FALSE)->execute();
+    $media = Media::load(end($medias));
+    // Verify that base field populates.
+    $this->assertNotEmpty($media->get('phish')->getString());
+
+    // Test also with a non-batch process. We're testing also --kill here.
+    $this->drush(DevelGenerateCommands::MEDIA, ['7'], [
+      'media-types' => $media_type1->id() . ',' . $media_type2->id(),
+      'kill' => NULL,
+    ]);
+    $this->assertCount(7, \Drupal::entityQuery('media')
+      ->accessCheck(FALSE)
+      ->execute());
+  }
+
+}

modules/devel/devel_generate/tests/src/Traits/DevelGenerateSetupTrait.php

@@ -0,0 +1,109 @@
+<?php
+
+namespace Drupal\Tests\devel_generate\Traits;
+
+use Drupal\comment\Tests\CommentTestTrait;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\Core\Language\Language;
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\taxonomy\Entity\Vocabulary;
+use Drupal\Tests\field\Traits\EntityReferenceFieldCreationTrait;
+
+/**
+ * Provides methods to assist Devel Generate testing.
+ *
+ * Referenced in DevelGenerateBrowserTestBase and DevelGenerateCommandsTest.
+ */
+trait DevelGenerateSetupTrait {
+
+  use CommentTestTrait;
+  use EntityReferenceFieldCreationTrait;
+
+  /**
+   * Vocabulary for testing generation of terms.
+   *
+   * @var \Drupal\taxonomy\VocabularyInterface
+   */
+  protected $vocabulary;
+
+  /**
+   * Second vocabulary for testing generation of terms.
+   *
+   * @var \Drupal\taxonomy\VocabularyInterface
+   */
+  protected $vocabulary2;
+
+  /**
+   * General set-up for all tests.
+   */
+  public function setUpData(): void {
+    // Create user with devel_generate permissions and access to admin/content.
+    $admin_user = $this->drupalCreateUser([
+      'administer devel_generate',
+      'access devel information',
+      'access content overview',
+    ]);
+    $this->drupalLogin($admin_user);
+
+    $entity_type_manager = $this->container->get('entity_type.manager');
+    // Create Basic page and Article node types.
+    if ($this->profile != 'standard') {
+      $this->drupalCreateContentType(['type' => 'page', 'name' => 'Basic Page']);
+      $this->drupalCreateContentType(['type' => 'article', 'name' => 'Article']);
+      $this->addDefaultCommentField('node', 'article');
+    }
+
+    // Enable translation for article content type (but not for page).
+    \Drupal::service('content_translation.manager')->setEnabled('node', 'article', TRUE);
+    // Create languages for generated translations.
+    ConfigurableLanguage::createFromLangcode('ca')->save();
+    ConfigurableLanguage::createFromLangcode('de')->save();
+    ConfigurableLanguage::createFromLangcode('fr')->save();
+
+    // Creating a vocabulary to associate taxonomy terms generated.
+    $this->vocabulary = Vocabulary::create([
+      'name' => 'Vocab 1 ' . $this->randomString(15),
+      'description' => $this->randomMachineName(),
+      'vid' => 'vocab_1_' . mb_strtolower($this->randomMachineName()),
+      'langcode' => Language::LANGCODE_NOT_SPECIFIED,
+    ]);
+    $this->vocabulary->save();
+    // Enable translation for terms in this vocabulary.
+    \Drupal::service('content_translation.manager')->setEnabled('taxonomy_term', $this->vocabulary->id(), TRUE);
+
+    // Creates a field of an entity reference field storage on article.
+    $field_name = 'taxonomy_' . $this->vocabulary->id();
+
+    $handler_settings = [
+      'target_bundles' => [
+        $this->vocabulary->id() => $this->vocabulary->id(),
+      ],
+      'auto_create' => TRUE,
+    ];
+    $this->createEntityReferenceField('node', 'article', $field_name, '', 'taxonomy_term', 'default', $handler_settings, FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED);
+
+    $entity_type_manager->getStorage('entity_form_display')
+      ->load('node.article.default')
+      ->setComponent($field_name, [
+        'type' => 'options_select',
+      ])
+      ->save();
+
+    $entity_type_manager->getStorage('entity_view_display')
+      ->load('node.article.default')
+      ->setComponent($field_name, [
+        'type' => 'entity_reference_label',
+      ])
+      ->save();
+
+    // Create the second vocabulary.
+    $this->vocabulary2 = Vocabulary::create([
+      'name' => 'Vocab 2 ' . $this->randomString(15),
+      'vid' => 'vocab_2_' . mb_strtolower($this->randomMachineName()),
+      'langcode' => Language::LANGCODE_NOT_SPECIFIED,
+    ]);
+    $this->vocabulary2->save();
+
+  }
+
+}

modules/devel/devel_generate/tests/src/Unit/DevelGenerateManagerTest.php

@@ -0,0 +1,110 @@
+<?php
+
+namespace Drupal\Tests\devel_generate\Unit;
+
+use Drupal\Component\Datetime\TimeInterface;
+use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
+use Drupal\Core\Cache\CacheBackendInterface;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\Entity\EntityFieldManagerInterface;
+use Drupal\Core\Entity\EntityTypeManager;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\StringTranslation\TranslationInterface;
+use Drupal\devel_generate\DevelGeneratePluginManager;
+use Drupal\devel_generate_example\Plugin\DevelGenerate\ExampleDevelGenerate;
+use Drupal\Tests\UnitTestCase;
+use PHPUnit\Framework\MockObject\MockObject;
+
+/**
+ * @coversDefaultClass \Drupal\devel_generate\DevelGeneratePluginManager
+ * @group devel_generate
+ */
+class DevelGenerateManagerTest extends UnitTestCase {
+
+  /**
+   * The plugin discovery.
+   */
+  protected MockObject|DiscoveryInterface $discovery;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    // Mock the plugin discovery.
+    $this->discovery = $this->createMock(DiscoveryInterface::class);
+    $this->discovery->expects($this->any())
+      ->method('getDefinitions')
+      ->willReturnCallback(function (): array {
+        return $this->getMockDefinitions();
+      });
+  }
+
+  /**
+   * Test creating an instance of the DevelGenerateManager.
+   */
+  public function testCreateInstance(): void {
+    $namespaces = new \ArrayObject(['Drupal\devel_generate_example' => realpath(__DIR__ . '/../../../modules/devel_generate_example/lib')]);
+    $cache_backend = $this->createMock(CacheBackendInterface::class);
+    $module_handler = $this->createMock(ModuleHandlerInterface::class);
+    $entity_type_manager = $this->createMock(EntityTypeManager::class);
+    $messenger = $this->createMock(MessengerInterface::class);
+    $language_manager = $this->createMock(LanguageManagerInterface::class);
+    $string_translation = $this->createMock(TranslationInterface::class);
+    $entityFieldManager = $this->createMock(EntityFieldManagerInterface::class);
+
+    $manager = new DevelGeneratePluginManager(
+      $namespaces,
+      $cache_backend,
+      $module_handler,
+      $entity_type_manager,
+      $messenger,
+      $language_manager,
+      $string_translation,
+      $entityFieldManager,
+    );
+
+    // Use reflection to set the protected discovery property.
+    $reflection = new \ReflectionClass($manager);
+    $property = $reflection->getProperty('discovery');
+    $property->setValue($manager, $this->discovery);
+
+    $container = new ContainerBuilder();
+    $time = $this->createMock(TimeInterface::class);
+    $container->set('entity_type.manager', $entity_type_manager);
+    $container->set('messenger', $messenger);
+    $container->set('language_manager', $language_manager);
+    $container->set('module_handler', $module_handler);
+    $container->set('string_translation', $string_translation);
+    $container->set('entity_field.manager', $entityFieldManager);
+    $container->set('datetime.time', $time);
+    \Drupal::setContainer($container);
+
+    $example_instance = $manager->createInstance('devel_generate_example');
+    $plugin_def = $example_instance->getPluginDefinition();
+
+    $this->assertInstanceOf(ExampleDevelGenerate::class, $example_instance);
+    $this->assertArrayHasKey('url', $plugin_def);
+    $this->assertTrue($plugin_def['url'] == 'devel_generate_example');
+  }
+
+  /**
+   * Callback function to return mock definitions.
+   *
+   * @return array
+   *   The mock of devel generate plugin definitions.
+   */
+  public function getMockDefinitions(): array {
+    return [
+      'devel_generate_example' => [
+        'id' => 'devel_generate_example',
+        'class' => ExampleDevelGenerate::class,
+        'url' => 'devel_generate_example',
+        'dependencies' => [],
+      ],
+    ];
+  }
+
+}