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Date: Tue, 10 Nov 2015 16:48:54 +0000
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Subject: PHP7 / foreach / references / ugly code / discrepancy to PHP 5.6
From: phofstetter@sensational.ch (Philip Hofstetter)

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Hi,

I'm having a cause of slightly ugly code that runs differently from PHP 5.6
to PHP 7 and I don't think this difference is documented, nor expected. As
I'm not sure whether this is an intended change or not, I'm asking here
firstr before making a bug report.

The code in question is

----
$b =3D [1, 2, 3];

foreach($b ?: [] as &$v){
    $v =3D $v*2;
    unset($v);
}

var_dump($b);
----
in PHP7, this produces

array(3) {
  [0] =3D>
  int(1)
  [1] =3D>
  int(2)
  [2] =3D>
  int(3)
}

whereas in PHP 5.6 and earlier, this produces

array(3) {
  [0] =3D>
  int(2)
  [1] =3D>
  int(4)
  [2] =3D>
  int(6)
}

what scares me about this is that in order to get the old behaviour in PHP7
back, you just have to get rid of the ?: operator:

foreach($b as &$v){

is fine

foreach($b ?: [] as &$v){

is not.

I guess this is related to
http://php.net/manual/en/migration70.incompatible.php#migration70.incompati=
ble.foreach.by-value
 or
http://php.net/manual/en/migration70.incompatible.php#migration70.incompati=
ble.foreach.by-ref,
but I'm not entirely sure whether this is actually intended behaviour -
it's certainly unexpected to me that applying ?: now always makes a copy
whereas before it didn't.

Philip



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