int|float for DateTime::setTimestamp

[divinity76]

just like the constructor accepts

new DateTime("@0.123456"); // 1970-01-01 00:00:00.123456
new DateTime("@".microtime(true));

now setTimestamp accepts it too:

$dt->setTimestamp(0.123456); // 1970-01-01 00:00:00.123456
$dt->setTimestamp(microtime(true));

resolves #13376

[SakiTakamachi]

The changes look good to me.

But the following code:

<?php
var_dump((new DateTime)->setTimestamp(microtime(true)));

This is interpreted as an int and works, albeit with a warning. So, strictly speaking, this is a BC break.

I honestly don't know if an RFC is necessary for this.

[divinity76]

nah it's all good, it will still work, just with higher accuracy and less warnings.
the BC break is inconsequential and borderline academic

I would be more worried about changing DateTime::getTimestamp to return float (that one might need a bool $as_float=false; argument)

[SakiTakamachi]

In the case of the following code, the comparison result will change:

<?php

$d1 = (new DateTime)->setTimestamp(microtime(true));
$d2 = (new DateTime)->setTimestamp(microtime(true));

if ($1 < $d2) {
    // any
}

I don't know if this kind of code is actually used....

[divinity76]

@SakiTakamachi that code is bugged and will randomly return true/false even today, the code:

$t1 = new DateTime();
$t2 = new DateTime();
$attempts = 0;
echo "it usually returns false\n";
while(!($t1->setTimestamp(time()) < $t2->setTimestamp(time()))) {
    ++$attempts;
}
echo "but after $attempts attempts it returns true\n";

outputs

it usually returns false
but after 2475192 attempts it returns true

[SakiTakamachi]

Yes, that's right. So I'm not sure if I should treat this as a BC Break. I'd like to wait for other people's opinions.

[divinity76]

¯\_(ツ)_/¯ i'll ask on the mailing list

[kocsismate]

the PR looks good to me.

[kocsismate]

nit: the same spaces vs tab "issue" here as well

[derickr]

Please address @kocsismate's coding standard comments. Indentation is with spaces in .c files. (It also now conflicts, so please rebase on master too).