Hi
thank you Andreas, that mostly matches what I would have answered
myself. I'll add my own nuance in a separate reply to Mirco directly.
On 2026-10-01 17:57, Andreas Heigl wrote:
But all that is obsoleted and irrelevant in the end as the Instant is
based on the epoch which is based on UTC minus leap-seconds. At least
as far as I understood Tim.
Yes, or “POSIX time”, which avoids the overloaded term UTC that could
also refer to the UTC timezone. Timezones reintroduce “date and time” as
a concept, which is not relevant to a point in time.
I have demonstrated it is impossible to write an adapter. Given the
constraint that only the PSR-20 MyClock class can be changed,
call-sites
must not be adjusted. Also the purpose of a PSR-20 Clock is to never
call `new DateTimeImmutable()` or `time()` anymore, so the assumption
there
are `new DateTimeImmutable()` calls that can be adapted is incorrect.
An adapter does never need to implement both interfaces. In essence an
adapter only needs to implement "the other" interface. A ClockAdapter
uses a ClockInterface to create an Instant whereas a
ClockInterfaceAdapter uses a Clock to create a DateTime. 2 classes that
seem rather straight forward.
Indeed. Here's an example implementation for both directions. The
`NativeToPsr20` adapter truncates to microseconds and needs to “invent”
a timezone. The opinionated choices made there should be correct for the
vast majority of users:
final readonly class Psr20ToNative implements \Time\Clock
{
public function __construct(
private \Psr\Clock\ClockInterface $clock,
) {}
public function now(): \Time\Instant
{
return $this->clock->now()->toInstant();
}
}
final readonly class NativeToPsr20 implements
\Psr\Clock\ClockInterface
{
public function __construct(
private \Time\Clock $clock,
private \DateTimeZone $timezone = new \DateTimeZone('UTC'),
) {}
public function now(): \DateTimeImmutable
{
$now = $this->clock->now();
return
\DateTimeImmutable::createFromTimestamp($now->getUnixTimestamp())
->setMicrosecond(\intdiv($now->getNanoseconds(), 1_000))
->setTimezone($this->timezone);
}
}
Best regards
Tim Düsterhus
