From 3635e97510190926ddc8137c31293f00534a9bba Mon Sep 17 00:00:00 2001
From: jrfnl <jrfnl@users.noreply.github.com>
Date: Thu, 8 Jul 2021 11:21:34 +0200
Subject: [PATCH] PHPMailer::setLanguage(): fix "lang_country" codes do not
 fall back to "lang"

When the  `$langCode` is passed as "language code - country code" and no translation is found for the specified country variant, the localization would automatically fall back to English, even when there was a viable translation available in the "parent" language, i.e. just based on the _language code_.

This commit changes the logic in the `PHPMailer::setLanguage()` method for when a "lang-country" code is passed.
It will now try and find a "lang-country" file first, if not found, it will try to find a file for just the "lang" and only if that could also not be found, it will fall back to English.

Related to 2418 - observation 2

Includes using named subpatterns in the regex to make the regex self-documenting.

Includes removing a commented out line of code which is superseded anyway.
---
 src/PHPMailer.php | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 0742ab81..25ac1791 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -2251,19 +2251,32 @@ class PHPMailer
         //Validate $langcode
         $foundlang = true;
         $langcode  = strtolower($langcode);
-        if (!preg_match('/^[a-z]{2}(?:_[a-z]{2})?$/', $langcode) && $langcode !== 'en') {
+        if (!preg_match('/^(?P<lang>[a-z]{2})(?P<country>_[a-z]{2})?$/', $langcode, $matches) && $langcode !== 'en') {
             $foundlang = false;
             $langcode = 'en';
         }
 
-        $lang_file = $lang_path . 'phpmailer.lang-' . $langcode . '.php';
         //There is no English translation file
         if ('en' !== $langcode) {
-            //Make sure language file path is readable
-            if (!static::fileIsAccessible($lang_file)) {
+            $langcodes = [];
+            if (!empty($matches['country'])) {
+                $langcodes[] = $matches['lang'] . $matches['country'];
+            }
+            $langcodes[] = $matches['lang'];
+
+            //Try and find a readable language file for the requested language.
+            $foundFile = false;
+            foreach ($langcodes as $code) {
+                $lang_file = $lang_path . 'phpmailer.lang-' . $code . '.php';
+                if (static::fileIsAccessible($lang_file)) {
+                    $foundFile = true;
+                    break;
+                }
+            }
+
+            if ($foundFile === false) {
                 $foundlang = false;
             } else {
-                //$foundlang = include $lang_file;
                 $lines = file($lang_file);
                 foreach ($lines as $line) {
                     //Translation file lines look like this: