fix: case-insensitivity in the like() method when in use with accented characters

Author: michalsn

system/Database/BaseBuilder.php

@@ -1151,7 +1151,7 @@ protected function _like($field, string $match = '', string $type = 'AND ', stri
 
         foreach ($keyValue as $k => $v) {
             if ($insensitiveSearch === true) {
-                $v = strtolower($v);
+                $v = mb_strtolower($v);
             }
 
             $prefix = empty($this->{$clause}) ? $this->groupGetType('') : $this->groupGetType($type);

tests/_support/Database/Seeds/CITestSeeder.php

@@ -86,6 +86,10 @@ public function run(): void
                     'key'   => 'key',
                     'value' => 'value',
                 ],
+                [
+                    'key'   => 'accented characters',
+                    'value' => 'śćźżłąęó',
+                ],
             ],
             'type_test' => [
                 [

tests/system/Database/Live/LikeTest.php

@@ -75,6 +75,14 @@ public function testLikeCaseInsensitive(): void
         $this->assertSame('Developer', $job->name);
     }
 
+    public function testLikeCaseInsensitiveWithAccentedCharacter(): void
+    {
+        $wai = $this->db->table('without_auto_increment')->like('value', 'ŁĄ', 'both', null, true)->get();
+        $wai = $wai->getRow();
+
+        $this->assertSame('accented characters', $wai->key);
+    }
+
     public function testOrLike(): void
     {
         $jobs = $this->db->table('job')->like('name', 'ian')

user_guide_src/source/changelogs/v4.5.6.rst

@@ -32,6 +32,7 @@ Bugs Fixed
 - **Session Library:** The session initialization debug message now uses the correct log type "debug" instead of "info".
 
 - **Validation:** Fixed the `getValidated()` method that did not return valid data when validation rules used multiple asterisks.
+- **Database:** Fixed the case insensitivity option in the ``like()`` method when dealing with accented characters.
 
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_