Add new TemplateEngine->testInstall method

- Add admin summary template engine error messages

src/Module/Admin/Summary.php

@@ -31,7 +31,9 @@ use Friendica\Database\DBStructure;
 use Friendica\DI;
 use Friendica\Model\Register;
 use Friendica\Module\BaseAdmin;
+use Friendica\Module\Update\Profile;
 use Friendica\Network\HTTPException\InternalServerErrorException;
+use Friendica\Render\FriendicaSmarty;
 use Friendica\Util\ConfigFileLoader;
 use Friendica\Util\DateTimeFormat;
 use Friendica\Util\Network;
@@ -46,6 +48,14 @@ class Summary extends BaseAdmin
 
 		// are there MyISAM tables in the DB? If so, trigger a warning message
 		$warningtext = [];
+
+		$templateEngine = Renderer::getTemplateEngine();
+		$errors = [];
+		$templateEngine->testInstall($errors);
+		foreach ($errors as $error) {
+			$warningtext[] = DI::l10n()->t('Template engine (%s) error: %s', $templateEngine::$name, $error);
+		}
+
 		if (DBA::count(['information_schema' => 'tables'], ['engine' => 'myisam', 'table_schema' => DBA::databaseName()])) {
 			$warningtext[] = DI::l10n()->t('Your DB still runs with MyISAM tables. You should change the engine type to InnoDB. As Friendica will use InnoDB only features in the future, you should change this! See <a href="%s">here</a> for a guide that may be helpful converting the table engines. You may also use the command <tt>php bin/console.php dbstructure toinnodb</tt> of your Friendica installation for an automatic conversion.<br />', 'https://dev.mysql.com/doc/refman/5.7/en/converting-tables-to-innodb.html');
 		}
@@ -136,7 +146,6 @@ class Summary extends BaseAdmin
 						throw new InternalServerErrorException('Stream is null.');
 					}
 				}
-
 			} catch (\Throwable $exception) {
 				$warningtext[] = DI::l10n()->t('The debug logfile \'%s\' is not usable. No logging possible (error: \'%s\')', $file, $exception->getMessage());
 			}

src/Render/FriendicaSmartyEngine.php

@@ -53,6 +53,14 @@ final class FriendicaSmartyEngine extends TemplateEngine
 		}
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	public function testInstall(array &$errors = null)
+	{
+		$this->smarty->testInstall($errors);
+	}
+
 	/**
 	 * @inheritDoc
 	 */

src/Render/TemplateEngine.php

@@ -40,6 +40,14 @@ abstract class TemplateEngine
 	 */
 	abstract public function __construct(string $theme, array $theme_info);
 
+	/**
+	 * Checks the template engine is correctly installed and configured and reports error messages in the provided
+	 * parameter or displays them directly if it's null.
+	 *
+	 * @param array|null $errors
+	 */
+	abstract public function testInstall(array &$errors = null);
+
 	/**
 	 * Returns the rendered template output from the template string and variables
 	 *