Carbon addWeeks() function not working

Question

I am creating some dates with Carbon in PHP, but I seem to be doing something wrong.

This here is my code:

$start = Carbon::create(2015, rand(6,7), rand(1,30), 0);
$end = $start->addWeeks(3);

echo "start time: " . $start;
echo "<br />";
echo "end time: " . $end;

And the output of the above is two exact same dates, e.g.:

start time: 2015-07-01 00:00:00
end time: 2015-07-01 00:00:00

I reffered to the docs, which can be found here: http://carbon.nesbot.com/docs/#api-addsub. Does anybody know what am I doing wrong?

Answer 1

I haven't worked with Carbon yet but I'd say those Carbon object are mutable. Also most functions seem to return $this for method chaining (aka fluent interface).

Thus, when doing $end = $start->addWeeks(3); your $end is actually the same object as $start. (just an intelligent guess)

To avoid this try to either clone the object before manipulation (if possible) or create another one.

Version 1

$start = Carbon::create(2015, rand(6,7), rand(1,30), 0);
$end = clone $start;
$start->addWeeks(3);

Version 2

$start = Carbon::create(2015, rand(6,7), rand(1,30), 0);
$end = Carbon::create(2015, rand(6,7), rand(1,30), 0);
$start->addWeeks(3);