Strict Standards: Only variables should be passed by reference

[schwim2]

Hi there folks!

I was receiving the following error on a gallery script whose server's PHP got upgraded:

Strict Standards: Only variables should be passed by reference in /home/higher/public_html/gallery/includes/mg2_functions.php on line 650

  function medium($name) {
    $ext = strrchr($name, '.');
    if($ext !== false) {
	$name = substr($name, 0, -strlen($ext)) . "_medium." . end(explode('.',$name));  <~~ Problem line
    }
    return $name;
  }

  function thumb($name) {
    $ext = strrchr($name, '.');
    if($ext !== false) {
        $name = substr($name, 0, -strlen($ext)) . "_thumb." . end(explode('.',$name));  <~~ Problem line

}
return $name;
  }

I did some googling and it looked like the issue was with the end / explode in those two lines so I moved those two outside of the line, like so:

  function thumb($name) {
    $ext = strrchr($name, '.');
    if($ext !== false) {
		$extension = end(explode('.',$name));
        $name = substr($name, 0, -strlen($ext)) . "_thumb." . $extension;

}
return $name;
  }

Which effectively moved the error to the new line, so I broke that up into two:

  function thumb($name) {
    $ext = strrchr($name, '.');
    if($ext !== false) {
		$extension = explode('.',$name);
		$extension = end($extension);
        $name = substr($name, 0, -strlen($ext)) . "_thumb." . $extension;

}
return $name;
  }

Which got rid of the error. I'm wondering though, what's the deal with this error? Why is it important to only perform this type of thing on a var and not on a similar function nested inside it?

It's just a curiosity thing really. I don't know why it's a no-no the way it was handled initially.

Thanks for your time!

[Weedpacket]

Because functions return values, not variables. If a function (in this case, [man]end[/man]) expects a reference to a variable, then it will get upset if it isn't given a variable to refer to.

[schwim2]

The error didn't show up until and upgrade the the script continued working in spite of the error. Was it just determined that it was a safety issue at one point but not enough of one to stop it from happening or was it always a bad thing to do and my settings changed to warn of it during the PHP upgrade?

[NogDog]

It might be something where they've made a backwards-compatible change, but raise the strict warning as a suggestion that you update your code so that it's foward-compatible if they ever make it an outright error?

[Weedpacket]

Not knowing anything about the earlier setup or the new one or what PHP versions are being talked about in either case, it may or may not be relevant to point out that E_STRICT level messages weren't included in E_ALL until PHP 5.4.0.

Also, the message severity for passing by reference was upgraded from E_STRICT to E_NOTICE in PHP 7 (and E_STRICT itself is no longer used).

[dalecosp]

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