Scans a directory (excluding `vendor`) for `.php` files and identifies used PHP extensions.

identify_used_extensions.php

<?php

declare(strict_types=1);

error_reporting(E_ALL);

/**
 * Recursively scans a directory for PHP files while ignoring the "vendor" folder.
 *
 * @param string $directory The directory to scan.
 * @return array An array of file paths for all found PHP files.
 */
function getPhpFiles(string $directory): array
{
    $files = [];
    $iterator = new RecursiveIteratorIterator(
        new RecursiveCallbackFilterIterator(
            new RecursiveDirectoryIterator($directory, FilesystemIterator::SKIP_DOTS),
            function ($current) {
                return !($current->isDir() && basename($current->getPathname()) === 'vendor'); // Skip vendor folder.
            }
        ),
        RecursiveIteratorIterator::LEAVES_ONLY
    );

    foreach ($iterator as $file) {
        if ($file->isFile() && $file->getExtension() === 'php') {
            $files[] = $file->getPathname();
        }
    }

    return $files;
}

/**
 * Extracts a list of PHP extensions used in the provided PHP files.
 *
 * This function scans for function calls that belong to installed extensions.
 *
 * @param array $files An array of PHP file paths to scan.
 * @return array A unique list of detected PHP extensions.
 */
function extractUsedExtensions(array $files): array
{
    $extensions = [];
    $extensionFunctions = [];

    // Get all available PHP extensions and their functions.
    foreach (get_loaded_extensions() as $ext) {
        foreach (get_extension_funcs($ext) ?: [] as $func) {
            $extensionFunctions[$func] = $ext;
        }
    }

    foreach ($files as $file) {
        $content = file_get_contents($file);
        foreach ($extensionFunctions as $func => $ext) {
            if (preg_match("/\b$func\s*\(/i", $content)) {
                $extensions[] = $ext;
            }
        }
    }

    return array_unique($extensions);
}

$directory = !empty($argv[1]) ? $argv[1] : __DIR__;
$phpFiles = getPhpFiles($directory);
$usedExtensions = extractUsedExtensions($phpFiles);
echo PHP_EOL;
echo "Target path: $directory" . PHP_EOL;
echo "Used PHP extensions:" . PHP_EOL;

foreach ($usedExtensions as $extension) {
    echo "* $extension" . PHP_EOL;
}