From f8245696b31439b972035aa922cb8fca82a91384 Mon Sep 17 00:00:00 2001
From: Matthias Pigulla <mp@webfactory.de>
Date: Fri, 6 Dec 2019 21:51:12 +0000
Subject: [PATCH] Use strtr() instead of strtoupper() to avoid bogus results
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For examle the tr_TR locale will upper-case "i" to the
"latin capital letter i with dot above" İ.
---
 src/Monolog/Logger.php | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/Monolog/Logger.php b/src/Monolog/Logger.php
index 05dfc8179..e649af51b 100644
--- a/src/Monolog/Logger.php
+++ b/src/Monolog/Logger.php
@@ -527,8 +527,13 @@ public static function getLevelName($level)
      */
     public static function toMonologLevel($level)
     {
-        if (is_string($level) && defined(__CLASS__.'::'.strtoupper($level))) {
-            return constant(__CLASS__.'::'.strtoupper($level));
+        if (is_string($level)) {
+            // Contains chars of all log levels and avoids using strtoupper() which may have
+            // strange results depending on locale (for example, "i" will become "İ")
+            $upper = strtr($level, 'abcdefgilmnortuwy', 'ABCDEFGILMNORTUWY');
+            if (defined(__CLASS__.'::'.$upper)) {
+                return constant(__CLASS__ . '::' . $upper);
+            }
         }
 
         return $level;