PHP7 Constructor class name

问题:

I have a Laravel 4.2 application which works with PHP5 without any problems. Since I installed a new vagrant box running PHP7 an error appears as soon as I run a model where the name of a function is the same as the class name (relationship-function) like this:

<?php

use Illuminate\Database\Eloquent\SoftDeletingTrait;

class Participant extends \Eloquent
{

    use SoftDeletingTrait;

    [...]

    public function participant()
    {
        return $this->morphTo();
    }

    [...]    

}

I get the following error message:

Methods with the same name as their class will not be constructors in a future version of PHP; Participant has a deprecated constructor (View: ...)

So what I didn't know until today is, that in PHP4 methods with the same name were the contructor of a class. Hmm. I am really a bad programmer... But in this case, from my understanding of what is happening in PHP7, they correct a failure of mine as I never wanted to use this function as a constructor, since it defines only an Eloquent relationship.

But how can I get rid of this message? As I understand this, in PHP4 my code was buggy, but not in PHP7, right? If not necessary I do not want to refactor this function, as it is used in several places.

Can anybody explain what I am doing wrong and why it worked with older PHP versions?

Thanks!

回答1:

As I understand this, in PHP4 my code was buggy, but not in PHP7, right?

Not quite. PHP4-style constructors still work on PHP7, they are just been deprecated and they will trigger a Deprecated warning.

What you can do is define a __construct method, even an empty one, so that the php4-constructor method won't be called on a newly-created instance of the class.

class foo
{
    public function __construct()
    {
        // Constructor's functionality here, if you have any.
    }

    public function foo()
    {
        // PHP4-style constructor.
        // This will NOT be invoked, unless a sub-class that extends `foo` calls it.
        // In that case, call the new-style constructor to keep compatibility.
        self::__construct();
    }
}

new foo();

It worked with older PHP versions simply because constructors don't get return value. Every time you created a Participant instance, you implicitly call the participant method, that's all.

回答2:

PHP 4 style constructors (methods that have the same name as the class they are defined in) are deprecated, and will be removed in the future. PHP 7 will emit E_DEPRECATED if a PHP 4 constructor is the only constructor defined within a class. Classes that implement a __construct() method are unaffected.

<?php
    class foo {
        function foo() {
            echo 'I am the constructor';
         }
     }
?>

You can keep your old constructor but you need to add a new construct like that:

use Illuminate\Database\Eloquent\SoftDeletingTrait;

class Participant extends \Eloquent
{

    use SoftDeletingTrait;

    [...]

    public function __construct()
    {
        return $this->morphTo();
    }

    public function participant()
    {
        return $this->morphTo();
    }

    [...]    

}