fix: Time::createFromTimestamp() returns Time with UTC

system/I18n/TimeTrait.php

@@ -266,7 +266,8 @@ public static function createFromFormat($format, $datetime, $timezone = null)
     public static function createFromTimestamp(int $timestamp, $timezone = null, ?string $locale = null)
     {
         $time = new self(gmdate('Y-m-d H:i:s', $timestamp), 'UTC', $locale);
-        $timezone ??= 'UTC';
+
+        $timezone ??= date_default_timezone_get();
 
         return $time->setTimezone($timezone);
     }

tests/system/I18n/TimeTest.php

@@ -259,17 +259,21 @@ public function testCreateFromFormatWithInvalidFormat(): void
 
     public function testCreateFromTimestamp(): void
     {
-        // Set the timezone temporarily to UTC to make sure the test timestamp is correct
+        // Save the current timezone.
         $tz = date_default_timezone_get();
-        date_default_timezone_set('UTC');
 
-        $timestamp = strtotime('2017-03-18 midnight');
+        // Change the timezone other than UTC.
+        date_default_timezone_set('Asia/Tokyo'); // +09:00
 
-        date_default_timezone_set($tz);
+        $timestamp = strtotime('2017-03-18 midnight');
 
         $time = Time::createFromTimestamp($timestamp);
 
-        $this->assertSame(date('2017-03-18 00:00:00'), $time->toDateTimeString());
+        $this->assertSame('Asia/Tokyo', $time->getTimezone()->getName());
+        $this->assertSame('2017-03-18 00:00:00', $time->format('Y-m-d H:i:s'));
+
+        // Restore timezone.
+        date_default_timezone_set($tz);
     }
 
     public function testCreateFromTimestampWithTimezone(): void

user_guide_src/source/changelogs/v4.4.6.rst

@@ -14,6 +14,15 @@ Release Date: Unreleased
 BREAKING
 ********
 
+Time::createFromTimestamp()
+===========================
+
+A bug that caused :ref:`Time::createFromTimestamp() <time-createfromtimestamp>`
+to return a Time instance with a timezone of UTC has been fixed.
+
+Starting with this version, when you do not specify a timezone, a Time instance
+with the app's timezone is returned by default.
+
 ***************
 Message Changes
 ***************

user_guide_src/source/installation/upgrade_446.rst

@@ -20,6 +20,20 @@ Mandatory File Changes
 Breaking Changes
 ****************
 
+Time::createFromTimestamp() Timezone Change
+===========================================
+
+When you do not specify a timezone, now
+:ref:`Time::createFromTimestamp() <time-createfromtimestamp>` returns a Time
+instance with the app's timezone is returned.
+
+If you want to keep the timezone UTC, you need to call ``setTimezone('UTC')``::
+
+    use CodeIgniter\I18n\Time;
+
+    $time = Time::createFromTimestamp(1501821586)->setTimezone('UTC');
+
+
 *********************
 Breaking Enhancements
 *********************

user_guide_src/source/libraries/time.rst

@@ -114,13 +114,18 @@ and returns a ``Time`` instance, instead of DateTimeImmutable:
 
 .. literalinclude:: time/011.php
 
+.. _time-createfromtimestamp:
+
 createFromTimestamp()
 =====================
 
 This method takes a UNIX timestamp and, optionally, the timezone and locale, to create a new Time instance:
 
 .. literalinclude:: time/012.php
 
+.. note:: Due to a bug, prior to v4.4.6, this method returned a Time instance
+    in timezone UTC when you do not specify a timezone.
+
 createFromInstance()
 ====================