Fix so output of log_date_format with microseconds contains time in server time zone, not UTC

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Fix so output of log_date_format with microseconds contains time in server time zone, not UTC
 - Fix so N property always exists in a vCard export (#8771)
 - Fix so rcmail::format_date() works with DateTimeImmutable input (#8867)
 - Fix bug where a non-ASCII character in app.js could cause error in javascript engine (#8894)

program/lib/Roundcube/rcube_utils.php

@@ -1479,12 +1479,17 @@ class rcube_utils
         }
 
         if (strpos($format, 'u') !== false) {
-            $dt  = number_format(microtime(true), 6, '.', '');
-            $dt .=  '.' . date_default_timezone_get();
+            $dt = number_format(microtime(true), 6, '.', '');
+
+            try {
+                $date = date_create_from_format('U.u', $dt);
+                $date->setTimeZone(new DateTimeZone(date_default_timezone_get()));
 
-            if ($date = date_create_from_format('U.u.e', $dt)) {
                 return $date->format($format);
             }
+            catch (Exception) {
+                // ignore, fallback to date()
+            }
         }
 
         return date($format);

tests/Framework/Utils.php

@@ -7,6 +7,22 @@
  */
 class Framework_Utils extends PHPUnit\Framework\TestCase
 {
+    /**
+     * Test for rcube_utils::date_format()
+     */
+    function test_date_format()
+    {
+        date_default_timezone_set('Europe/Berlin');
+
+        $this->assertSame(date('d-M-Y H:i:s O'), rcube_utils::date_format());
+        $this->assertSame(date('Y-m-d H:i:s O'), rcube_utils::date_format('Y-m-d H:i:s O'));
+
+        $result = rcube_utils::date_format('H:i:s,u O');
+        $regexp = '/^' . preg_quote(date('H:i:s,')) . '(?<!000000)\d{6}' . preg_quote(date(' O')) . '$/';
+
+        $this->assertMatchesRegularExpression($regexp, $result);
+    }
+
     /**
      * Test for rcube_utils::explode()
      */