Php7 Constructor Class Name

PHP7 Constructor class name

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.

How to make PHP version 8 support constructor with same name as class?

This isn't a case of a setting that you can turn back on, I'm afraid, the functionality was permanently removed from PHP. It might be possible to write some kind of extension which emulated the old behaviour, but it's going to be a lot more work in the long run than doing a one-off fix to all your existing files.

Your best bet is probably to use a tool such as Rector which can automate the upgrade process. In this case, using the Php4ConstructorRector rule looks like it should do it all for you.

__construct() vs SameAsClassName() for constructor in PHP

I agree with gizmo, the advantage is so you don't have to rename it if you rename your class. DRY.

Similarly, if you have a child class you can call

parent::__construct()

to call the parent constructor. If further down the track you change the class the child class inherits from, you don't have to change the construct call to the parent.

It seems like a small thing, but missing changing the constructor call name to your parents classes could create subtle (and not so subtle) bugs.

For example, if you inserted a class into your heirachy, but forgot to change the constructor calls, you could started calling constructors of grandparents instead of parents. This could often cause undesirable results which might be difficult to notice.

Also note that

As of PHP 5.3.3, methods with the same name as the last element of a namespaced class name will no longer be treated as constructor. This change doesn't affect non-namespaced classes.

Source: http://php.net/manual/en/language.oop5.decon.php

php 7 deprecated constructor issue

In a very old version of PHP (PHP 4, to be precise), having a function name with the same name as the class was used as the constructor.

That is, if you were to call new my_function(), the method my_function inside the class would be called with any parameters.

Now, if you're using the my_function as a constructor, a drop-in replacement would be to rename it to __construct. That will work whenever an instance is initiated.

If, on the other hand, you just happen to have a function that shares a name with the class, and are not relying on it as a constructor, you should be able to ignore that warning altogether, as it's referencing a deprecated functionality that you're not using.

Edit: If it's the second scenario, make sure to also add a public function __construct(), if there's not one there already. Leaving it empty is fine, but just having it will make sure PHP doesn't inadvertently try to call my_function on instantiation, as the __construct will take precedence.

Example:

<?php

class Foo
{
    //DEPRECATED CONSTRUCTOR SYNTAX (Don't try this at home.)
    public function Foo()
    {
        echo "Foo named constructor\n"; 
    } 
}

$f = new Foo();
//Foo named constructor

class Bar
{
    public function __construct()
    {
        echo "Bar constructor\n";
    }

    public function Bar()
    {
        echo "Bar function\n";
    }
}

$b = new Bar();
//Bar constructor
$b->Bar();
//Bar function

Migrating PHP 7 to 8 - Object's constructor is not called

Propably incompatible changes.
From docs:

Methods with the same name as the class are no longer interpreted as constructors. The __construct() method should be used instead.

Source: https://www.php.net/manual/en/migration80.incompatible.php

Use of deprecated PHP4 style class constructor is not supported since PHP 7

Change the function to:

function __construct($indent = '  ') {
  $this->indent = $indent;
  $this->xml = '<?xml version="1.0" encoding="utf-8"?>'."\n";
}

As you used to be able to define constructors via the class name and that has been deprecated as of PHP 7:

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.

The error example, as per the documentation:

Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; foo has a deprecated constructor in example.php on line 3

Regex to replace function name in PHP classes

As said in the comments, better use a scripting language, some logic and a two-factor-approach:

1. Match the class including the class name as "a whole" using a recursive approach
2. Replace the function with the class name with __construct

---

In PHP:

<?php

$class_regex = '~
        ^\s*class\s+
        (?P<class>\S+)[^{}]+(\{
        (?:[^{}]*|(?2))*
        \})~mx';

$data = preg_replace_callback($class_regex, 
    function($match) {
        $function_regex = '~function\s+\K'.$match['class'].'~';
        return preg_replace($function_regex, '__construct', $match[0]);
    },
    $data);

echo $data;
?>

See a demo for the outer regex on regex101.com and for the whole code on ideone.com.

---

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