From cf0a453f08726aa4a326fdba746e12e93032a4d8 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Thu, 16 Jan 2020 00:26:08 +0000
Subject: [PATCH] Date/Time: Use `wp_date()` to display the correct time of the
 next DST transition in Timezone setting on General Settings screen.

Props Rarst, autotutorial.
Fixes #49038.

git-svn-id: https://develop.svn.wordpress.org/trunk@47073 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/options-general.php | 26 ++++++--------------------
 1 file changed, 6 insertions(+), 20 deletions(-)

diff --git a/src/wp-admin/options-general.php b/src/wp-admin/options-general.php
index d5c3d167c4..cbde314eef 100644
--- a/src/wp-admin/options-general.php
+++ b/src/wp-admin/options-general.php
@@ -276,34 +276,20 @@ if ( empty( $tzstring ) ) { // Create a UTC+- zone if no timezone string exists
 	?>
 	<br />
 	<?php
-	$allowed_zones = timezone_identifiers_list();
+	if ( in_array( $tzstring, timezone_identifiers_list() ) ) {
+		$transitions = timezone_transitions_get( timezone_open( $tzstring ), time() );
 
-	if ( in_array( $tzstring, $allowed_zones ) ) {
-		$found                   = false;
-		$date_time_zone_selected = new DateTimeZone( $tzstring );
-		$tz_offset               = timezone_offset_get( $date_time_zone_selected, date_create() );
-		$right_now               = time();
-		foreach ( timezone_transitions_get( $date_time_zone_selected ) as $tr ) {
-			if ( $tr['ts'] > $right_now ) {
-				$found = true;
-				break;
-			}
-		}
-
-		if ( $found ) {
+		// 0 index is the state at current time, 1 index is the next transition, if any.
+		if ( ! empty( $transitions[1] ) ) {
 			echo ' ';
-			$message = $tr['isdst'] ?
+			$message = $transitions[1]['isdst'] ?
 				/* translators: %s: Date and time. */
 				__( 'Daylight saving time begins on: %s.' ) :
 				/* translators: %s: Date and time. */
 				__( 'Standard time begins on: %s.' );
-			// Add the difference between the current offset and the new offset to ts to get the correct transition time from date_i18n().
 			printf(
 				$message,
-				'<code>' . date_i18n(
-					__( 'F j, Y' ) . ' ' . __( 'g:i a' ),
-					$tr['ts'] + ( $tz_offset - $tr['offset'] )
-				) . '</code>'
+				'<code>' . wp_date( __( 'F j, Y' ) . ' ' . __( 'g:i a' ), $transitions[1]['ts'] ) . '</code>'
 			);
 		} else {
 			_e( 'This timezone does not observe daylight saving time.' );