[TASK] Deprecate register functions

Classes/Service/MailTemplateService.php

@@ -802,9 +802,13 @@ class MailTemplateService {
 	 * If found, register the template(s)
 	 *
 	 * @throws \BadFunctionCallException
+	 * @deprecated since 4.7.0 will be removed in 5.0.0
 	 * @return array
 	 */
 	public static function registerExtensions(): array {
+		// @TODO remove this deprecated function in version 5.0.0
+		self::logDeprecation('registerExtensions');
+
 		// clear registerArray
 		$registerArray = [];
 
@@ -850,12 +854,16 @@ class MailTemplateService {
 	 * @param array $configArray
 	 * @param bool $transformTemplateFolder
 	 * @param string $storeTemplateExtension
+	 * @deprecated since 4.7.0 will be removed in 5.0.0
 	 * @return array
 	 */
 	private static function writeRegisterArrayEntry(
 		array $registerArray, $extensionKey, $templateKey, array $configArray,
 		$transformTemplateFolder = TRUE, $storeTemplateExtension = ''
 	) {
+		// @TODO remove this deprecated function in version 5.0.0
+		self::logDeprecation('writeRegisterArrayEntry');
+
 		// If it is not explicitly set in which extension the html should be located, use the extension set in the template settings
 		if ($storeTemplateExtension === '') {
 			$storeTemplateExtension = $extensionKey;
@@ -961,4 +969,15 @@ class MailTemplateService {
 
 		return $allMarker;
 	}
+
+	/**
+	 * function to call a deprecation log entry (but only once per request / class)
+	 *
+	 * @param $function
+	 */
+	private static function logDeprecation($function) {
+		GeneralUtility::deprecationLog(
+			'The function ' . $function . ' is deprecated since version 4.7.0 and will be removed in version 5.0.0'
+		);
+	}
 }