Generates a php.ini file compatible with PHP JIT compiler

generate-jit-php-ini.php

<?php

/**
 * Generates a php.ini file from runtime ini directives, excluding extensions incompatible with JIT.
 * I did not find a way to disable an extension from the command line, so this script is a workaround.
 *
 * Use it this way:
 *
 * php generate-jit-php-ini.php > php.ini
 * php -n -c php.ini
 */

declare(strict_types=1);

$zendExtensions = [
    'opcache.so',
];

$disableExtensions = [
    // These extensions are not compatible with JIT
    'xdebug.so',
    'pcov.so',

    // Not sure why, but on my setup enabling these extensions yields:
    // PHP Warning:  Module "xxx" is already loaded in Unknown on line 0
    'pdo_sqlite.so',
    'pdo.so',
    'posix.so',
];

/**
 * @var string $name
 * @var ?string $value
 */
foreach (ini_get_all(details: false) as $name => $value) {
    if ($value === null) {
        continue;
    }

    if ($name === 'extension_dir') {
        $i = new DirectoryIterator($value);

        foreach ($i as $file) {
            /** @var SplFileInfo $file */
            if (!$file->isFile() || $file->getExtension() !== 'so') {
                continue;
            }
            if (in_array($file->getFilename(), $disableExtensions, true)) {
                continue;
            }

            $directiveName = in_array($file->getFilename(), $zendExtensions, true)
                ? 'zend_extension'
                : 'extension';

            printf("%s=\"%s\"\n", $directiveName, $file->getPathname());
        }

        continue;
    }

    printf("%s=\"%s\"\n", $name, $value);
}

echo "opcache.jit_buffer_size=256M\n";