Issue #3084069 by Wim Leers, kamalzairig, zrpnr, tinko, webchick, lauriii, tedbow, ckrina: Allow marking themes as experimental

core/modules/system/src/Controller/SystemController.php

@@ -197,6 +197,7 @@ class SystemController extends ControllerBase {
       }
       $theme->is_default = ($theme->getName() == $theme_default);
       $theme->is_admin = ($theme->getName() == $admin_theme || ($theme->is_default && empty($admin_theme)));
+      $theme->is_experimental = isset($theme->info['experimental']) && $theme->info['experimental'];
 
       // Identify theme screenshot.
       $theme->screenshot = NULL;
@@ -269,7 +270,7 @@ class SystemController extends ControllerBase {
               'attributes' => ['title' => $this->t('Set @theme as default theme', ['@theme' => $theme->info['name']])],
             ];
           }
-          $admin_theme_options[$theme->getName()] = $theme->info['name'];
+          $admin_theme_options[$theme->getName()] = $theme->info['name'] . ($theme->is_experimental ? ' (' . t('Experimental') . ')' : '');
         }
         else {
           $theme->operations[] = [
@@ -287,7 +288,8 @@ class SystemController extends ControllerBase {
         }
       }
 
-      // Add notes to default and administration theme.
+      // Add notes to default theme, administration theme and experimental
+      // themes.
       $theme->notes = [];
       if ($theme->is_default) {
         $theme->notes[] = $this->t('default theme');
@@ -295,6 +297,9 @@ class SystemController extends ControllerBase {
       if ($theme->is_admin) {
         $theme->notes[] = $this->t('administration theme');
       }
+      if ($theme->is_experimental) {
+        $theme->notes[] = $this->t('experimental theme');
+      }
 
       // Sort installed and uninstalled themes into their own groups.
       $theme_groups[$theme->status ? 'installed' : 'uninstalled'][] = $theme;

core/modules/system/src/Controller/ThemeController.php

@@ -6,8 +6,10 @@ use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Config\PreExistingConfigException;
 use Drupal\Core\Config\UnmetDependenciesException;
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\Core\Extension\ThemeExtensionList;
 use Drupal\Core\Extension\ThemeHandlerInterface;
 use Drupal\Core\Extension\ThemeInstallerInterface;
+use Drupal\system\Form\ThemeExperimentalConfirmForm;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
@@ -24,6 +26,13 @@ class ThemeController extends ControllerBase {
    */
   protected $themeHandler;
 
+  /**
+   * An extension discovery instance.
+   *
+   * @var \Drupal\Core\Extension\ThemeExtensionList
+   */
+  protected $themeList;
+
   /**
    * The theme installer service.
    *
@@ -36,13 +45,16 @@ class ThemeController extends ControllerBase {
    *
    * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
    *   The theme handler.
+   * @param \Drupal\Core\Extension\ThemeExtensionList $theme_list
+   *   The theme extension list.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
    * @param \Drupal\Core\Extension\ThemeInstallerInterface $theme_installer
    *   The theme installer.
    */
-  public function __construct(ThemeHandlerInterface $theme_handler, ConfigFactoryInterface $config_factory, ThemeInstallerInterface $theme_installer) {
+  public function __construct(ThemeHandlerInterface $theme_handler, ThemeExtensionList $theme_list, ConfigFactoryInterface $config_factory, ThemeInstallerInterface $theme_installer) {
     $this->themeHandler = $theme_handler;
+    $this->themeList = $theme_list;
     $this->configFactory = $config_factory;
     $this->themeInstaller = $theme_installer;
   }
@@ -53,6 +65,7 @@ class ThemeController extends ControllerBase {
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('theme_handler'),
+      $container->get('extension.list.theme'),
       $container->get('config.factory'),
       $container->get('theme_installer')
     );
@@ -106,8 +119,9 @@ class ThemeController extends ControllerBase {
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   A request object containing a theme name and a valid token.
    *
-   * @return \Symfony\Component\HttpFoundation\RedirectResponse
-   *   Redirects back to the appearance admin page.
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|array
+   *   Redirects back to the appearance admin page or the confirmation form
+   *   if an experimental theme will be installed.
    *
    * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
    *   Throws access denied when no theme or token is set in the request or when
@@ -117,6 +131,11 @@ class ThemeController extends ControllerBase {
     $theme = $request->query->get('theme');
 
     if (isset($theme)) {
+      // Display confirmation form in case of experimental theme.
+      if ($this->willInstallExperimentalTheme($theme)) {
+        return $this->formBuilder()->getForm(ThemeExperimentalConfirmForm::class, $theme);
+      }
+
       try {
         if ($this->themeInstaller->install([$theme])) {
           $themes = $this->themeHandler->listInfo();
@@ -149,14 +168,38 @@ class ThemeController extends ControllerBase {
     throw new AccessDeniedHttpException();
   }
 
+  /**
+   * Checks if the given theme requires the installation of experimental themes.
+   *
+   * @param string $theme
+   *   The name of the theme to check.
+   *
+   * @return bool
+   *   Whether experimental themes will be installed.
+   */
+  protected function willInstallExperimentalTheme($theme) {
+    $all_themes = $this->themeList->getList();
+    $dependencies = array_keys($all_themes[$theme]->requires);
+    $themes_to_enable = array_merge([$theme], $dependencies);
+
+    foreach ($themes_to_enable as $name) {
+      if (!empty($all_themes[$name]->info['experimental']) && $all_themes[$name]->status === 0) {
+        return TRUE;
+      }
+    }
+
+    return FALSE;
+  }
+
   /**
    * Set the default theme.
    *
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   A request object containing a theme name.
    *
-   * @return \Symfony\Component\HttpFoundation\RedirectResponse
-   *   Redirects back to the appearance admin page.
+   * @return \Symfony\Component\HttpFoundation\RedirectResponse|array
+   *   Redirects back to the appearance admin page or the confirmation form
+   *   if an experimental theme will be installed.
    *
    * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
    *   Throws access denied when no theme is set in the request.
@@ -168,6 +211,10 @@ class ThemeController extends ControllerBase {
     if (isset($theme)) {
       // Get current list of themes.
       $themes = $this->themeHandler->listInfo();
+      // Display confirmation form if an experimental theme is being installed.
+      if ($this->willInstallExperimentalTheme($theme)) {
+        return $this->formBuilder()->getForm(ThemeExperimentalConfirmForm::class, $theme, TRUE);
+      }
 
       // Check if the specified theme is one recognized by the system.
       // Or try to install the theme.

core/modules/system/src/Form/ThemeExperimentalConfirmForm.php

@@ -0,0 +1,189 @@
+<?php
+
+namespace Drupal\system\Form;
+
+use Drupal\Core\Config\PreExistingConfigException;
+use Drupal\Core\Config\UnmetDependenciesException;
+use Drupal\Core\Extension\ThemeExtensionList;
+use Drupal\Core\Extension\ThemeInstallerInterface;
+use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Url;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Builds a confirmation form for enabling experimental themes.
+ *
+ * @internal
+ */
+class ThemeExperimentalConfirmForm extends ConfirmFormBase {
+
+  /**
+   * An extension discovery instance.
+   *
+   * @var \Drupal\Core\Extension\ThemeExtensionList
+   */
+  protected $themeList;
+
+  /**
+   * The theme installer service.
+   *
+   * @var \Drupal\Core\Extension\ThemeInstallerInterface
+   */
+  protected $themeInstaller;
+
+  /**
+   * Constructs a ThemeExperimentalConfirmForm object.
+   *
+   * @param \Drupal\Core\Extension\ThemeExtensionList $theme_list
+   *   The theme extension list.
+   * @param \Drupal\Core\Extension\ThemeInstallerInterface $theme_installer
+   *   The theme installer.
+   */
+  public function __construct(ThemeExtensionList $theme_list, ThemeInstallerInterface $theme_installer) {
+    $this->themeList = $theme_list;
+    $this->themeInstaller = $theme_installer;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('extension.list.theme'),
+      $container->get('theme_installer')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getQuestion() {
+    return $this->t('Are you sure you wish to install an experimental theme?');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCancelUrl() {
+    return new Url('system.themes_page');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getConfirmText() {
+    return $this->t('Continue');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDescription() {
+    return $this->t('Would you like to continue with the above?');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'system_themes_experimental_confirm_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+    $theme = $form_state->getBuildInfo()['args'][0] ? $form_state->getBuildInfo()['args'][0] : NULL;
+    $all_themes = $this->themeList->getList();
+    if (!isset($all_themes[$theme])) {
+      return $this->redirect('system.themes_page');
+    }
+    $this->messenger()->addWarning($this->t('Experimental themes are provided for testing purposes only. Use at your own risk.'));
+
+    $dependencies = array_keys($all_themes[$theme]->requires);
+    $themes = array_merge([$theme], $dependencies);
+    $is_experimental = function ($theme) use ($all_themes) {
+      return isset($all_themes[$theme]) && isset($all_themes[$theme]->info['experimental']) && $all_themes[$theme]->info['experimental'];
+    };
+    $get_label = function ($theme) use ($all_themes) {
+      return $all_themes[$theme]->info['name'];
+    };
+
+    $items = [];
+    if (!empty($dependencies)) {
+      // Display a list of required themes that have to be installed as well.
+      $items[] = $this->formatPlural(count($dependencies), 'You must enable the @required theme to install @theme.', 'You must enable the @required themes to install @theme.', [
+        '@theme' => $get_label($theme),
+        // It is safe to implode this because theme names are not translated
+        // markup and so will not be double-escaped.
+        '@required' => implode(', ', array_map($get_label, $dependencies)),
+      ]);
+    }
+    // Add the list of experimental themes after any other messages.
+    $items[] = $this->t('The following themes are experimental: @themes', ['@themes' => implode(', ', array_map($get_label, array_filter($themes, $is_experimental)))]);
+    $form['message'] = [
+      '#theme' => 'item_list',
+      '#items' => $items,
+    ];
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    $args = $form_state->getBuildInfo()['args'];
+    $theme = isset($args[0]) ? $args[0] : NULL;
+    $set_default = isset($args[1]) ? $args[1] : FALSE;
+    $themes = $this->themeList->getList();
+    $config = $this->configFactory()->getEditable('system.theme');
+    try {
+      if ($this->themeInstaller->install([$theme])) {
+        if ($set_default) {
+          // Set the default theme.
+          $config->set('default', $theme)->save();
+
+          // The status message depends on whether an admin theme is currently
+          // in use: an empty string means the admin theme is set to be the
+          // default theme.
+          $admin_theme = $config->get('admin');
+          if (!empty($admin_theme) && $admin_theme !== $theme) {
+            $this->messenger()
+              ->addStatus($this->t('Please note that the administration theme is still set to the %admin_theme theme; consequently, the theme on this page remains unchanged. All non-administrative sections of the site, however, will show the selected %selected_theme theme by default.', [
+                '%admin_theme' => $themes[$admin_theme]->info['name'],
+                '%selected_theme' => $themes[$theme]->info['name'],
+              ]));
+          }
+          else {
+            $this->messenger()->addStatus($this->t('%theme is now the default theme.', ['%theme' => $themes[$theme]->info['name']]));
+          }
+        }
+        else {
+          $this->messenger()->addStatus($this->t('The %theme theme has been installed.', ['%theme' => $themes[$theme]->info['name']]));
+        }
+      }
+      else {
+        $this->messenger()->addError($this->t('The %theme theme was not found.', ['%theme' => $theme]));
+      }
+    }
+    catch (PreExistingConfigException $e) {
+      $config_objects = $e->flattenConfigObjects($e->getConfigObjects());
+      $this->messenger()->addError(
+        $this->formatPlural(
+          count($config_objects),
+          'Unable to install @extension, %config_names already exists in active configuration.',
+          'Unable to install @extension, %config_names already exist in active configuration.',
+          [
+            '%config_names' => implode(', ', $config_objects),
+            '@extension' => $theme,
+          ])
+      );
+    }
+    catch (UnmetDependenciesException $e) {
+      $this->messenger()->addError($e->getTranslatedMessage($this->getStringTranslation(), $theme));
+    }
+    $form_state->setRedirectUrl($this->getCancelUrl());
+  }
+
+}

core/modules/system/system.install

@@ -65,18 +65,33 @@ function system_requirements($phase) {
     }
 
     // Warn if any experimental modules are installed.
-    $experimental = [];
+    $experimental_modules = [];
     $enabled_modules = \Drupal::moduleHandler()->getModuleList();
     foreach ($enabled_modules as $module => $data) {
       $info = \Drupal::service('extension.list.module')->getExtensionInfo($module);
       if (isset($info['package']) && $info['package'] === 'Core (Experimental)') {
-        $experimental[$module] = $info['name'];
+        $experimental_modules[$module] = $info['name'];
       }
     }
-    if (!empty($experimental)) {
-      $requirements['experimental'] = [
+    if (!empty($experimental_modules)) {
+      $requirements['experimental_modules'] = [
         'title' => t('Experimental modules enabled'),
-        'value' => t('Experimental modules found: %module_list. <a href=":url">Experimental modules</a> are provided for testing purposes only. Use at your own risk.', ['%module_list' => implode(', ', $experimental), ':url' => 'https://www.drupal.org/core/experimental']),
+        'value' => t('Experimental modules found: %module_list. <a href=":url">Experimental modules</a> are provided for testing purposes only. Use at your own risk.', ['%module_list' => implode(', ', $experimental_modules), ':url' => 'https://www.drupal.org/core/experimental']),
+        'severity' => REQUIREMENT_WARNING,
+      ];
+    }
+    // Warn if any experimental themes are installed.
+    $experimental_themes = [];
+    $installed_themes = \Drupal::service('theme_handler')->listInfo();
+    foreach ($installed_themes as $theme => $data) {
+      if (isset($data->info['experimental']) && $data->info['experimental']) {
+        $experimental_themes[$theme] = $data->info['name'];
+      }
+    }
+    if (!empty($experimental_themes)) {
+      $requirements['experimental_themes'] = [
+        'title' => t('Experimental themes enabled'),
+        'value' => t('Experimental themes found: %theme_list. Experimental themes are provided for testing purposes only. Use at your own risk.', ['%theme_list' => implode(', ', $experimental_themes)]),
         'severity' => REQUIREMENT_WARNING,
       ];
     }

core/modules/system/tests/src/Functional/Theme/ExperimentalThemeTest.php

@@ -0,0 +1,128 @@
+<?php
+
+namespace Drupal\Tests\system\Functional\Theme;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests the installation of themes.
+ *
+ * @group Theme
+ */
+class ExperimentalThemeTest extends BrowserTestBase {
+
+  /**
+   * The admin user.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->adminUser = $this->drupalCreateUser(['access administration pages', 'administer themes']);
+    $this->drupalLogin($this->adminUser);
+  }
+
+  /**
+   * Tests installing experimental themes and dependencies in the UI.
+   */
+  public function testExperimentalConfirmForm() {
+    // Only experimental themes should be marked as such with a parenthetical.
+    $this->drupalGet('admin/appearance');
+    $this->assertText(sprintf('Experimental test %s                (experimental theme)', \Drupal::VERSION));
+    $this->assertText(sprintf('Experimental dependency test %s', \Drupal::VERSION));
+
+    // First, test installing a non-experimental theme with no dependencies.
+    // There should be no confirmation form and no experimental theme warning.
+    $this->drupalGet('admin/appearance');
+    $this->cssSelect('a[title="Install <strong>Test theme</strong> theme"]')[0]->click();
+    $this->assertText('The &lt;strong&gt;Test theme&lt;/strong&gt; theme has been installed.');
+    $this->assertNoText('Experimental modules are provided for testing purposes only.');
+
+    // Next, test installing an experimental theme with no dependencies.
+    // There should be a confirmation form with an experimental warning, but no
+    // list of dependencies.
+    $this->drupalGet('admin/appearance');
+    $this->cssSelect('a[title="Install Experimental test theme"]')[0]->click();
+    $this->assertText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+
+    // The module should not be enabled and there should be a warning and a
+    // list of the experimental modules with only this one.
+    $this->assertNoText('The Experimental Test theme has been installed.');
+    $this->assertText('Experimental themes are provided for testing purposes only.');
+
+    // There should be no message about enabling dependencies.
+    $this->assertNoText('You must enable');
+
+    // Enable the theme and confirm that it worked.
+    $this->drupalPostForm(NULL, [], 'Continue');
+    $this->assertText('The Experimental test theme has been installed.');
+
+    // Setting it as the default should not ask for another confirmation.
+    $this->cssSelect('a[title="Set Experimental test as default theme"]')[0]->click();
+    $this->assertNoText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+    $this->assertText('Experimental test is now the default theme.');
+    $this->assertNoText(sprintf('Experimental test %s                (experimental theme)', \Drupal::VERSION));
+    $this->assertText(sprintf('Experimental test %s                (default theme, administration theme, experimental theme)', \Drupal::VERSION));
+
+    // Uninstall the theme.
+    $this->config('system.theme')->set('default', 'test_theme')->save();
+    \Drupal::service('theme_handler')->refreshInfo();
+    \Drupal::service('theme_installer')->uninstall(['experimental_theme_test']);
+
+    // Reinstall the same experimental theme, but this time immediately set it
+    // as the default. This should again trigger a confirmation form with an
+    // experimental warning.
+    $this->drupalGet('admin/appearance');
+    $this->cssSelect('a[title="Install Experimental test as default theme"]')[0]->click();
+    $this->assertText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+
+    // Test enabling a theme that is not itself experimental, but that depends
+    // on an experimental module.
+    $this->drupalGet('admin/appearance');
+    $this->cssSelect('a[title="Install Experimental dependency test theme"]')[0]->click();
+
+    // The theme should not be enabled and there should be a warning and a
+    // list of the experimental modules with only this one.
+    $this->assertNoText('The Experimental dependency test theme has been installed.');
+    $this->assertText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+    $this->assertText('The following themes are experimental: Experimental test');
+
+    // Ensure the non-experimental theme is not listed as experimental.
+    $this->assertNoText('The following themes are experimental: Experimental test, Experimental dependency test');
+    $this->assertNoText('The following themes are experimental: Experimental dependency test');
+
+    // There should be a message about enabling dependencies.
+    $this->assertText('You must enable the Experimental test theme to install Experimental dependency test');
+
+    // Enable the theme and confirm that it worked.
+    $this->drupalPostForm(NULL, [], 'Continue');
+    $this->assertText('The Experimental dependency test theme has been installed.');
+    $this->assertText(sprintf('Experimental test %s                (experimental theme)', \Drupal::VERSION));
+    $this->assertText(sprintf('Experimental dependency test %s', \Drupal::VERSION));
+
+    // Setting it as the default should not ask for another confirmation.
+    $this->cssSelect('a[title="Set Experimental dependency test as default theme"]')[0]->click();
+    $this->assertNoText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+    $this->assertText('Experimental dependency test is now the default theme.');
+    $this->assertText(sprintf('Experimental test %s                (experimental theme)', \Drupal::VERSION));
+    $this->assertText(sprintf('Experimental dependency test %s                (default theme, administration theme)', \Drupal::VERSION));
+
+    // Uninstall the theme.
+    $this->config('system.theme')->set('default', 'test_theme')->save();
+    \Drupal::service('theme_handler')->refreshInfo();
+    \Drupal::service('theme_installer')->uninstall(['experimental_theme_test', 'experimental_theme_dependency_test']);
+
+    // Reinstall the same theme, but this time immediately set it as the
+    // default. This should again trigger a confirmation form with an
+    // experimental warning for its dependency.
+    $this->drupalGet('admin/appearance');
+    $this->cssSelect('a[title="Install Experimental dependency test as default theme"]')[0]->click();
+    $this->assertText('Experimental themes are provided for testing purposes only. Use at your own risk.');
+  }
+
+}

core/modules/system/tests/themes/experimental_theme_dependency_test/experimental_theme_dependency_test.info.yml

@@ -0,0 +1,6 @@
+name: 'Experimental dependency test'
+type: theme
+description: 'Experimental dependency test theme.'
+version: VERSION
+core: 8.x
+base theme: experimental_theme_test

core/modules/system/tests/themes/experimental_theme_test/experimental_theme_test.info.yml

@@ -0,0 +1,7 @@
+name: 'Experimental test'
+type: theme
+description: 'Experimental test theme.'
+version: VERSION
+core: 8.x
+base theme: false
+experimental: true