Fix customized timezone guesser

lib/TimezoneGuesser/GuessFromCustomizedTimeZone.php

@@ -45,11 +45,12 @@ public function guess(VTimeZone $vtimezone, ?bool $failIfUncertain = false): ?\D
         $daylightIterator = $daylight ? new RRuleIterator($daylightRRule, $standardIterator->current()) : null;
         $daylightIterator && $daylightIterator->next();
 
+        $day = 24 * 60 * 60;
         foreach ($timezones as $timezone) {
             $tz = new \DateTimeZone($timezone);
             // check standard
             $timestamp = $standardIterator->current()->getTimestamp();
-            $transitions = $tz->getTransitions($timestamp, $timestamp + 1);
+            $transitions = $tz->getTransitions($timestamp + $day, $timestamp + $day + 1);
             if (empty($transitions)) {
                 continue;
             }
@@ -66,7 +67,7 @@ public function guess(VTimeZone $vtimezone, ?bool $failIfUncertain = false): ?\D
 
             // check daylight
             $timestamp = $daylightIterator->current()->getTimestamp();
-            $transitions = $tz->getTransitions($timestamp, $timestamp + 1);
+            $transitions = $tz->getTransitions($timestamp + $day, $timestamp + $day + 1);
             if (empty($transitions)) {
                 continue;
             }

tests/VObject/TimeZoneUtilTest.php

@@ -671,6 +671,49 @@ public function testCustomizedTimeZone(): void
         self::assertSame(11 * 60 * 60, $tz->getOffset($start));
     }
 
+    public function testCustomizedTimeZone2(): void
+    {
+        $ics = <<<ICS
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//ical.marudot.com//iCal Event Maker 
+X-WR-CALNAME:test
+NAME:test
+CALSCALE:GREGORIAN
+BEGIN:VTIMEZONE
+TZID:Customized Time Zone
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTAMP:20200907T032724Z
+UID:[email protected]
+DTSTART;TZID=Customized Time Zone:20210611T110000
+DTEND;TZID=Customized Time Zone:20210611T113000
+SUMMARY:customized time zone
+END:VEVENT
+END:VCALENDAR
+ICS;
+
+        $tz = TimeZoneUtil::getTimeZone('Customized Time Zone', Reader::read($ics));
+        self::assertNotSame('Customized Time Zone', $tz->getName());
+        $start = new \DateTimeImmutable('2022-04-25');
+        self::assertSame(2 * 60 * 60, $tz->getOffset($start));
+
+        $start = new \DateTimeImmutable('2022-11-10');
+        self::assertSame(60 * 60, $tz->getOffset($start));
+    }
+
     public function testCustomizedTimeZoneWithoutDaylight(): void
     {
         $ics = $this->getCustomizedICS();