Remove most calls to date_default_timezone_* calls

- It was wrongly used to set the node-wide ot user-specific timezone
- It is now fully managed from the App object
- Add a static variable to DateTimeFormat maintain the convenient local() method

mod/events.php

@@ -100,9 +100,9 @@ function events_post(App $a)
 	}
 
 	if ($adjust) {
-		$start = DateTimeFormat::convert($start, 'UTC', date_default_timezone_get());
+		$start = DateTimeFormat::convert($start, 'UTC', $a->getTimeZone());
 		if (!$nofinish) {
-			$finish = DateTimeFormat::convert($finish, 'UTC', date_default_timezone_get());
+			$finish = DateTimeFormat::convert($finish, 'UTC', $a->getTimeZone());
 		}
 	} else {
 		$start = DateTimeFormat::utc($start);
@@ -481,9 +481,9 @@ function events_content(App $a)
 		$sdt = $orig_event['start'] ?? 'now';
 		$fdt = $orig_event['finish'] ?? 'now';
 
-		$tz = date_default_timezone_get();
+		$tz = $a->getTimeZone();
 		if (isset($orig_event['adjust'])) {
-			$tz = ($orig_event['adjust'] ? date_default_timezone_get() : 'UTC');
+			$tz = ($orig_event['adjust'] ? $a->getTimeZone() : 'UTC');
 		}
 
 		$syear  = DateTimeFormat::convert($sdt, $tz, 'UTC', 'Y');

mod/item.php

@@ -686,7 +686,7 @@ function item_post(App $a) {
 	Hook::callAll('post_local',$datarray);
 
 	if (!empty($_REQUEST['scheduled_at'])) {
-		$scheduled_at = DateTimeFormat::convert($_REQUEST['scheduled_at'], 'UTC', $a->getTimezone());
+		$scheduled_at = DateTimeFormat::convert($_REQUEST['scheduled_at'], 'UTC', $a->getTimeZone());
 		if ($scheduled_at > DateTimeFormat::utcNow()) {
 			unset($datarray['created']);
 			unset($datarray['edited']);

mod/settings.php

@@ -333,7 +333,7 @@ function settings_post(App $a)
 	}
 
 	if (($timezone != $user['timezone']) && strlen($timezone)) {
-		date_default_timezone_set($timezone);
+		$a->setTimeZone($timezone);
 	}
 
 	$aclFormatter = DI::aclFormatter();
@@ -601,7 +601,7 @@ function settings_content(App $a)
 	$expire_network_only = DI::pConfig()->get(local_user(), 'expire', 'network_only', false);
 
 	if (!strlen($user['timezone'])) {
-		$timezone = date_default_timezone_get();
+		$timezone = $a->getTimeZone();
 	}
 
 	// Set the account type to "Community" when the page is a community page but the account type doesn't fit

src/App.php

@@ -40,6 +40,7 @@ use Friendica\Model\Profile;
 use Friendica\Module\Special\HTTPException as ModuleHTTPException;
 use Friendica\Network\HTTPException;
 use Friendica\Util\ConfigFileLoader;
+use Friendica\Util\DateTimeFormat;
 use Friendica\Util\HTTPSignature;
 use Friendica\Util\Profiler;
 use Friendica\Util\Strings;
@@ -217,12 +218,13 @@ class App
 	/**
 	 * Set the timezone
 	 *
-	 * @param int $timezone
+	 * @param string $timezone A valid time zone identifier, see https://www.php.net/manual/en/timezones.php
 	 * @return void
 	 */
 	public function setTimeZone(string $timezone)
 	{
-		$this->timezone = $timezone;
+		$this->timezone = (new \DateTimeZone($timezone))->getName();
+		DateTimeFormat::setLocalTimeZone($this->timezone);
 	}
 
 	/**
@@ -338,6 +340,9 @@ class App
 	{
 		set_time_limit(0);
 
+		// Ensure that all "strtotime" operations do run timezone independent
+		date_default_timezone_set('UTC');
+
 		// This has to be quite large to deal with embedded private photos
 		ini_set('pcre.backtrack_limit', 500000);
 
@@ -372,15 +377,13 @@ class App
 	private function loadDefaultTimezone()
 	{
 		if ($this->config->get('system', 'default_timezone')) {
-			$this->timezone = $this->config->get('system', 'default_timezone');
+			$timezone = $this->config->get('system', 'default_timezone', 'UTC');
 		} else {
 			global $default_timezone;
-			$this->timezone = !empty($default_timezone) ? $default_timezone : 'UTC';
+			$timezone = $default_timezone ?? '' ?: 'UTC';
 		}
 
-		if ($this->timezone) {
+		$this->setTimeZone($timezone);
-			date_default_timezone_set($this->timezone);
-		}
 	}
 
 	/**

src/Core/Worker.php

@@ -61,9 +61,6 @@ class Worker
 	 */
 	public static function processQueue($run_cron = true)
 	{
-		// Ensure that all "strtotime" operations do run timezone independent
-		date_default_timezone_set('UTC');
-
 		self::$up_start = microtime(true);
 
 		// At first check the maximum load. We shouldn't continue with a high load

src/Module/Conversation/Network.php

@@ -372,10 +372,10 @@ class Network extends BaseModule
 		}
 
 		if (self::$dateFrom) {
-			$conditionStrings = DBA::mergeConditions($conditionStrings, ["`received` <= ? ", DateTimeFormat::convert(self::$dateFrom, 'UTC', date_default_timezone_get())]);
+			$conditionStrings = DBA::mergeConditions($conditionStrings, ["`received` <= ? ", DateTimeFormat::convert(self::$dateFrom, 'UTC', DI::app()->getTimeZone())]);
 		}
 		if (self::$dateTo) {
-			$conditionStrings = DBA::mergeConditions($conditionStrings, ["`received` >= ? ", DateTimeFormat::convert(self::$dateTo, 'UTC', date_default_timezone_get())]);
+			$conditionStrings = DBA::mergeConditions($conditionStrings, ["`received` >= ? ", DateTimeFormat::convert(self::$dateTo, 'UTC', DI::app()->getTimeZone())]);
 		}
 
 		if (self::$groupId) {

src/Module/Profile/Status.php

@@ -151,10 +151,10 @@ class Status extends BaseProfile
 		}
 
 		if (!empty($datequery)) {
-			$condition = DBA::mergeConditions($condition, ["`received` <= ?", DateTimeFormat::convert($datequery, 'UTC', date_default_timezone_get())]);
+			$condition = DBA::mergeConditions($condition, ["`received` <= ?", DateTimeFormat::convert($datequery, 'UTC', $a->getTimeZone())]);
 		}
 		if (!empty($datequery2)) {
-			$condition = DBA::mergeConditions($condition, ["`received` >= ?", DateTimeFormat::convert($datequery2, 'UTC', date_default_timezone_get())]);
+			$condition = DBA::mergeConditions($condition, ["`received` >= ?", DateTimeFormat::convert($datequery2, 'UTC', $a->getTimeZone())]);
 		}
 
 		// Does the profile page belong to a forum?

src/Protocol/DFRN.php

@@ -488,10 +488,7 @@ class DFRN
 			XML::addElement($doc, $author, "poco:note", $profile["about"]);
 			XML::addElement($doc, $author, "poco:preferredUsername", $profile["nickname"]);
 
-			$savetz = date_default_timezone_get();
+			XML::addElement($doc, $author, "poco:utcOffset", DateTimeFormat::timezoneNow($profile["timezone"], "P"));
-			date_default_timezone_set($profile["timezone"]);
-			XML::addElement($doc, $author, "poco:utcOffset", date("P"));
-			date_default_timezone_set($savetz);
 
 			if (trim($profile["homepage"]) != "") {
 				$urls = $doc->createElement("poco:urls");

src/Security/Authentication.php

@@ -305,7 +305,6 @@ class Authentication
 		$this->session->set('new_member', time() < ($member_since + (60 * 60 * 24 * 14)));
 
 		if (strlen($user_record['timezone'])) {
-			date_default_timezone_set($user_record['timezone']);
 			$a->setTimeZone($user_record['timezone']);
 		}
 

src/Util/DateTimeFormat.php

@@ -36,6 +36,13 @@ class DateTimeFormat
 	const HTTP  = 'D, d M Y H:i:s \G\M\T';
 	const JSON  = 'Y-m-d\TH:i:s.v\Z';
 
+	static $localTimezone = 'UTC';
+
+	public static function setLocalTimeZone(string $timezone)
+	{
+		self::$localTimezone = $timezone;
+	}
+
 	/**
 	 * convert() shorthand for UTC.
 	 *
@@ -59,7 +66,7 @@ class DateTimeFormat
 	 */
 	public static function local($time, $format = self::MYSQL)
 	{
-		return self::convert($time, date_default_timezone_get(), 'UTC', $format);
+		return self::convert($time, self::$localTimezone, 'UTC', $format);
 	}
 
 	/**
@@ -160,7 +167,7 @@ class DateTimeFormat
 			$to_obj = new DateTimeZone('UTC');
 		}
 
-		$d->setTimeZone($to_obj);
+		$d->setTimezone($to_obj);
 
 		return $d->format($format);
 	}

src/Util/Temporal.php

@@ -361,22 +361,18 @@ class Temporal
 	 * whose date of birth is provided.
 	 *
 	 * @param string $dob      Date of Birth
-	 * @param string $owner_tz  (optional) Timezone of the person of interest
+	 * @param string $timezone Timezone of the person of interest
 	 *
 	 * @return int Age in years
 	 * @throws \Exception
 	 */
-	public static function getAgeByTimezone($dob, $owner_tz = ''): int
+	public static function getAgeByTimezone(string $dob, string $timezone): int
 	{
 		if (!intval($dob)) {
 			return 0;
 		}
 
-		if (!$owner_tz) {
+		$birthdate = new DateTime($dob . ' 00:00:00', new DateTimeZone($timezone));
-			$owner_tz = date_default_timezone_get();
-		}
-
-		$birthdate = new DateTime($dob . ' 00:00:00', new DateTimeZone($owner_tz));
 		$currentDate = new DateTime('now', new DateTimeZone('UTC'));
 
 		$interval = $birthdate->diff($currentDate);