Isolated include

include_file.php

<?php
var_dump(get_defined_vars());

index.php

<?php
/**
 * Includes a file with an empty variable scope.
 * @param string $filePath The path to the file to include.
 * @param array|null $variables Key/value array with the variables that should be in the include file its scope.
 * @param bool $useRequire Wehter to use require() instead of include()
 */
function isolatedInclude($filePath, $variables = null, $useRequire = true) {
    unset($filePath, $variables, $useRequire);
    if (count(func_get_args()) >= 2 && func_get_arg(1) !== null) {
        extract(func_get_arg(1));
    }

    if (count(func_get_args()) < 3 || func_get_arg(2) === true) {
        require func_get_arg(0);
    } else {
        include func_get_arg(0);
    }
}

$parentScopeVariable1 = 'Parent variable 1';
$parentScopeVariable2 = 'Parent variable 2';

$includeScopeVariable1 = 'Include scope variable 1';
$includeScopeVariable2 = 'Include scope variable 2';
isolatedInclude('include_file.php', ['includeScopeVariable1' => $includeScopeVariable1, 'includeScopeVariable2' => $includeScopeVariable2]);

output.txt

array (size=2)
  'includeScopeVariable1' => string 'Include scope variable 1' (length=24)
  'includeScopeVariable2' => string 'Include scope variable 2' (length=24)