From d448c448caded1e826ade450e4351b6e5ae2341c Mon Sep 17 00:00:00 2001
From: Felix Arntz <flixos90@git.wordpress.org>
Date: Tue, 3 Jul 2018 15:58:58 +0000
Subject: [PATCH] Date/Time: Add support for `gmt_offset` to `date_i18n()`.

Prior to this change, `date_i18n()` only supported the `timezone_string` option, causing incorrect timezones to appear in formatted dates on sites that still rely on the `gmt_offset` option.

Props Rarst.
Fixes #34835.


git-svn-id: https://develop.svn.wordpress.org/trunk@43387 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/functions.php         | 30 +++++++++++++++++++++++++++
 tests/phpunit/tests/date/dateI18n.php | 16 ++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 3c4a301298..b4df760ec6 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -138,6 +138,36 @@ function date_i18n( $dateformatstring, $timestamp_with_offset = false, $gmt = fa
 					$dateformatstring = substr( $dateformatstring, 1, strlen( $dateformatstring ) - 1 );
 				}
 			}
+		} else {
+			$offset = get_option( 'gmt_offset' );
+			foreach ( $timezone_formats as $timezone_format ) {
+				if ( 'I' === $timezone_format ) {
+					continue;
+				}
+
+				if ( false !== strpos( $dateformatstring, $timezone_format ) ) {
+					if ( 'Z' === $timezone_format ) {
+						$formatted = (string) ( $offset * HOUR_IN_SECONDS );
+					} else {
+						$prefix    = '';
+						$hours     = (int) $offset;
+						$separator = '';
+						$minutes   = abs( ( $offset - $hours ) * 60 );
+
+						if ( 'T' === $timezone_format ) {
+							$prefix = 'GMT';
+						} elseif ( 'e' === $timezone_format || 'P' === $timezone_format ) {
+							$separator = ':';
+						}
+
+						$formatted = sprintf( '%s%+03d%s%02d', $prefix, $hours, $separator, $minutes );
+					}
+
+					$dateformatstring = ' ' . $dateformatstring;
+					$dateformatstring = preg_replace( "/([^\\\])$timezone_format/", "\\1" . backslashit( $formatted ), $dateformatstring );
+					$dateformatstring = substr( $dateformatstring, 1 );
+				}
+			}
 		}
 	}
 	$j = @date( $dateformatstring, $i );
diff --git a/tests/phpunit/tests/date/dateI18n.php b/tests/phpunit/tests/date/dateI18n.php
index e92f58de6f..d5685190c7 100644
--- a/tests/phpunit/tests/date/dateI18n.php
+++ b/tests/phpunit/tests/date/dateI18n.php
@@ -67,4 +67,20 @@ class Tests_Date_I18n extends WP_UnitTestCase {
 
 		$this->assertEquals( '2012-12-01 00:00:00 CST -06:00 America/Regina', date_i18n( 'Y-m-d H:i:s T P e', strtotime( '2012-12-01 00:00:00' ) ) );
 	}
+
+	/**
+	 * @ticket 34835
+	 */
+	public function test_gmt_offset_should_output_correct_timezone() {
+		$timezone_formats = 'P I O T Z e';
+		$timezone_string  = 'America/Regina';
+		$datetimezone     = new DateTimeZone( $timezone_string );
+		update_option( 'timezone_string', '' );
+		$offset = $datetimezone->getOffset( new DateTime() ) / 3600;
+		update_option( 'gmt_offset', $offset );
+		$datetime = new DateTime( 'now', $datetimezone );
+		$datetime = new DateTime( $datetime->format( 'P' ) );
+
+		$this->assertEquals( $datetime->format( $timezone_formats ), date_i18n( $timezone_formats ) );
+	}
 }