Variable variables in classes using PHP 7

Actually I’m migrating a bigger project from PHP 5.3.3 to PHP 7.1.13. In older versions of PHP it was possible to code following access to variable variables:

class MyClass {};
$myVar = array("hello","world");

$myClass = new MyClass();
$myClass->$myVar[0] = "test 0"; // sets "test 0" to $myClass->hello
$myClass->$myVar[1] = "test 1"; // sets "test 1" to $myClass->world
print_r($myClass);

This shows:

MyClass Object
(
    [hello] => test 0
    [world] => test 1
)

Using the same code in PHP 7 it shows:

MyClass Object
(
    [Array] => Array
        (
            [0] => test 0
            [1] => test 1
        )

)

In PHP 7 I figured out, that I have to use this way to get the same result:

$myClass->{$myVar[0]} = "test 0";
$myClass->{$myVar[1]} = "test 1";

I found in the documentation that php5 and php7 interpretate this on different ways: http://php.net/manual/en/migration70.incompatible.php#migration70.incompatible.variable-handling.indirect

Is there any chance to keep the old code or do I have to recode every appearance of this? Maybe some php.ini settings or something like this? Do you have any ideas?

Answer

I’m afraid not, as you already found out yourself PHP7 interprets this expression differently from PHP5. The manual explicitly states

Code that used the old right-to-left evaluation order must be rewritten to explicitly use that evaluation order with curly braces

So you’ll have to replace all the

$foo->$bar['baz']

With

$foo->{$bar['baz']}