Ticket #38771: Clarified_date_i18n_args_and_fixed_GMT_one_.patch

wp-includes/functions.php

@@ -70 +70 @@
 }
 
 /**
- * Retrieve the date in localized format, based on timestamp.
+ * Retrieve the date in localized format, based on a sum of Unix timestamp and timezone offset in seconds.
  *
  * If the locale specifies the locale month and weekday, then the locale will
  * take over the format for the date. If it isn't, then the date format string
@@ -80 +80 @@
  *
  * @global WP_Locale $wp_locale
  *
- * @param string   $dateformatstring Format to display the date.
- * @param bool|int $unixtimestamp    Optional. Unix timestamp. Default false.
- * @param bool     $gmt              Optional. Whether to use GMT timezone. Default false.
+ * @param string   $dateformatstring      Format to display the date.
+ * @param bool|int $timestamp_with_offset Optional. Accepts a sum of Unix timestamp and timezone offset in seconds. Default false.
+ * @param bool     $gmt                   Optional. Whether to use GMT timezone, only applies if timestamp is not provided. Default false.
  *
  * @return string The date, translated if locale specifies it.
  */
-function date_i18n( $dateformatstring, $unixtimestamp = false, $gmt = false ) {
+function date_i18n( $dateformatstring, $timestamp_with_offset = false, $gmt = false ) {
         global $wp_locale;
-        $i = $unixtimestamp;
+        $i = $timestamp_with_offset;
 
         if ( false === $i ) {
                 $i = current_time( 'timestamp', $gmt );
@@ -120 +120 @@
         $timezone_formats = array( 'P', 'I', 'O', 'T', 'Z', 'e' );
         $timezone_formats_re = implode( '|', $timezone_formats );
         if ( preg_match( "/$timezone_formats_re/", $dateformatstring ) ) {
-                $timezone_string = get_option( 'timezone_string' );
+                if ( false === $timestamp_with_offset && $gmt ) {
+                        $timezone_string = 'UTC';
+                } else {
+                        $timezone_string = get_option( 'timezone_string' );
+                }
                 if ( $timezone_string ) {
                         $timezone_object = timezone_open( $timezone_string );
                         $date_object = date_create( null, $timezone_object );