fix: Time::createFromTimestamp() sets incorrect time when specifying timezone

[totoprayogo1916]

Description
previously not updating date even though time zone has been set

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[kenjis]

@totoprayogo1916 I'm not sure what the intent of this PR is.
What do you mean Update Time::createFromTimestamp() ?
Can you add test code?

[totoprayogo1916]

case:

$time = new Time('now');
$timestamp = $time->timestamp;

$new_time = Time::createFromTimestamp($timestamp);
$new_time_timezone = Time::createFromTimestamp($timestamp, config('App')->appTimezone);

var_dump(
    $time->toDateTimeString(),
    $new_time->toDateTimeString(),
    $new_time_timezone->toDateTimeString()
);

and the results like:

The date doesn't change even though the timezone has been added.

[kenjis]

@totoprayogo1916 This is complicated timezone issue.
You must add test code to show the specification.

Note, we expect all code changes or bug-fixes to be accompanied by one or more tests added to our test suite to prove the code works. If pull requests are not accompanied by relevant tests, they will likely be closed.
https://github.com/codeigniter4/CodeIgniter4/blob/develop/contributing/pull_request.md#contributions

The date doesn't change even though the timezone has been added.

What's wrong with it?

[totoprayogo1916]

What's wrong with it?

Test added

[kenjis]

The time is changed when specify timezone.

$time = new Time('2022/01/18 00:00:00');
$new_time = Time::createFromTimestamp($time->timestamp);
$new_time_timezone = Time::createFromTimestamp($time->timestamp, 'Asia/Jakarta');

var_dump(
    $time->getTimestamp(),
    $new_time->getTimestamp(),
    $new_time_timezone->getTimestamp()
);

int(1642485600)
int(1642485600)
int(1642460400) // <- changed

[totoprayogo1916]

int(1642485600)
int(1642485600)
int(1642460400) // <- changed

timestamp changed, but Date not.
I posted yesterday here: https://forum.codeigniter.com/thread-81033.html

[totoprayogo1916]

var_dump(
    $time,
    $time->timestamp,
    $new_time,
    $new_time->timestamp,
    $new_time_timezone,
    $new_time_timezone->timestamp
);

[kenjis]

@totoprayogo1916

timestamp changed, but Date not.

I got what you mean when I saw your var_dump output.
Thanks.

[kenjis]

The timestamp is always based on UTC, so the current behavior is a bug, right?