From 91f60afbe51feb939144aa06d37017a4b6e1a516 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Mon, 19 Aug 2019 21:05:42 +0000
Subject: [PATCH] Date/Time: Use PHP `DateTime` class API in `current_time()`.

Only use the legacy WP timestamp approach (a sum of timestamp and timezone offset) for `timestamp` and `U` formats without the `$gmt` flag.

Otherwise, make sure the function returns correct local time for any format.

Props Rarst, jdgrimes.
Fixes #40653.

git-svn-id: https://develop.svn.wordpress.org/trunk@45856 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/functions.php            | 24 ++++++++++------
 tests/phpunit/tests/date/currentTime.php | 36 +++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 8e17499be0..857d16fd60 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -46,10 +46,11 @@ function mysql2date( $format, $date, $translate = true ) {
 }
 
 /**
- * Retrieve the current time based on specified type.
+ * Retrieves the current time based on specified type.
  *
  * The 'mysql' type will return the time in the format for MySQL DATETIME field.
- * The 'timestamp' type will return the current timestamp.
+ * The 'timestamp' type will return the current timestamp or a sum of timestamp
+ * and timezone offset, depending on `$gmt`.
  * Other strings will be interpreted as PHP date formats (e.g. 'Y-m-d').
  *
  * If $gmt is set to either '1' or 'true', then both types will use GMT time.
@@ -63,14 +64,19 @@ function mysql2date( $format, $date, $translate = true ) {
  * @return int|string Integer if $type is 'timestamp', string otherwise.
  */
 function current_time( $type, $gmt = 0 ) {
-	switch ( $type ) {
-		case 'mysql':
-			return ( $gmt ) ? gmdate( 'Y-m-d H:i:s' ) : gmdate( 'Y-m-d H:i:s', ( time() + ( get_option( 'gmt_offset' ) * HOUR_IN_SECONDS ) ) );
-		case 'timestamp':
-			return ( $gmt ) ? time() : time() + ( get_option( 'gmt_offset' ) * HOUR_IN_SECONDS );
-		default:
-			return ( $gmt ) ? gmdate( $type ) : gmdate( $type, time() + ( get_option( 'gmt_offset' ) * HOUR_IN_SECONDS ) );
+	// Don't use non-GMT timestamp, unless you know the difference and really need to.
+	if ( 'timestamp' === $type || 'U' === $type ) {
+		return $gmt ? time() : time() + (int) ( get_option( 'gmt_offset' ) * HOUR_IN_SECONDS );
 	}
+
+	if ( 'mysql' === $type ) {
+		$type = 'Y-m-d H:i:s';
+	}
+
+	$timezone = $gmt ? new DateTimeZone( 'UTC' ) : wp_timezone();
+	$datetime = new DateTime( 'now', $timezone );
+
+	return $datetime->format( $type );
 }
 
 /**
diff --git a/tests/phpunit/tests/date/currentTime.php b/tests/phpunit/tests/date/currentTime.php
index 209eb128c6..7cc88dbe3e 100644
--- a/tests/phpunit/tests/date/currentTime.php
+++ b/tests/phpunit/tests/date/currentTime.php
@@ -6,8 +6,10 @@
  */
 class Tests_Date_CurrentTime extends WP_UnitTestCase {
 
+	/**
+	 * @ticket 37440
+	 */
 	public function test_should_work_with_changed_timezone() {
-
 		$format          = 'Y-m-d H:i:s';
 		$timezone_string = 'America/Regina';
 		update_option( 'timezone_string', $timezone_string );
@@ -21,4 +23,36 @@ class Tests_Date_CurrentTime extends WP_UnitTestCase {
 		$this->assertEquals( gmdate( $format ), current_time( $format, true ) );
 		$this->assertEquals( $datetime->format( $format ), current_time( $format ) );
 	}
+
+	/**
+	 * @ticket 40653
+	 */
+	public function test_should_return_wp_timestamp() {
+		update_option( 'timezone_string', 'Europe/Kiev' );
+		$timestamp = time();
+		$datetime  = new DateTime( '@' . $timestamp );
+		$datetime->setTimezone( wp_timezone() );
+		$wp_timestamp = $timestamp + $datetime->getOffset();
+
+		$this->assertEquals( $timestamp, current_time( 'timestamp', true ), '', 2 );
+		$this->assertEquals( $timestamp, current_time( 'U', true ), '', 2 );
+		$this->assertEquals( $wp_timestamp, current_time( 'timestamp' ), '', 2 );
+		$this->assertEquals( $wp_timestamp, current_time( 'U' ), '', 2 );
+		$this->assertInternalType( 'int', current_time( 'timestamp' ) );
+	}
+
+	/**
+	 * @ticket 40653
+	 */
+	public function test_should_return_correct_local_time() {
+		update_option( 'timezone_string', 'Europe/Kiev' );
+		$timestamp      = time();
+		$datetime_local = new DateTime( '@' . $timestamp );
+		$datetime_local->setTimezone( wp_timezone() );
+		$datetime_utc = new DateTime( '@' . $timestamp );
+		$datetime_utc->setTimezone( new DateTimeZone( 'UTC' ) );
+
+		$this->assertEquals( $datetime_local->format( DATE_W3C ), current_time( DATE_W3C ), '', 2 );
+		$this->assertEquals( $datetime_utc->format( DATE_W3C ), current_time( DATE_W3C, true ), '', 2 );
+	}
 }