Php get recursive directory listing

Ready for copy and paste function for common use cases, improved/extended version of one answer above:

function getDirContents(string $dir, int $onlyFiles = 0, string $excludeRegex = '~/\.git/~', int $maxDepth = -1): array {
    $results = [];
    $scanAll = scandir($dir);
    sort($scanAll);
    $scanDirs = []; $scanFiles = [];
    foreach($scanAll as $fName){
        if ($fName === '.' || $fName === '..') { continue; }
        $fPath = str_replace(DIRECTORY_SEPARATOR, '/', realpath($dir . '/' . $fName));
        if (strlen($excludeRegex) > 0 && preg_match($excludeRegex, $fPath . (is_dir($fPath) ? '/' : ''))) { continue; }
        if (is_dir($fPath)) {
            $scanDirs[] = $fPath;
        } elseif ($onlyFiles >= 0) {
            $scanFiles[] = $fPath;
        }
    }

    foreach ($scanDirs as $pDir) {
        if ($onlyFiles <= 0) {
            $results[] = $pDir;
        }
        if ($maxDepth !== 0) {
            foreach (getDirContents($pDir, $onlyFiles, $excludeRegex, $maxDepth - 1) as $p) {
                $results[] = $p;
            }
        }
    }
    foreach ($scanFiles as $p) {
        $results[] = $p;
    }

    return $results;
}

And if you need relative paths:

function updateKeysWithRelPath(array $paths, string $baseDir, bool $allowBaseDirPath = false): array {
    $results = [];
    $regex = '~^' . preg_quote(str_replace(DIRECTORY_SEPARATOR, '/', realpath($baseDir)), '~') . '(?:/|$)~s';
    $regex = preg_replace('~/~', '/(?:(?!\.\.?/)(?:(?!/).)+/\.\.(?:/|$))?(?:\.(?:/|$))*', $regex); // limited to only one "/xx/../" expr
    if (DIRECTORY_SEPARATOR === '\\') {
        $regex = preg_replace('~/~', '[/\\\\\\\\]', $regex) . 'i';
    }
    foreach ($paths as $p) {
        $rel = preg_replace($regex, '', $p, 1);
        if ($rel === $p) {
            throw new \Exception('Path relativize failed, path "' . $p . '" is not within basedir "' . $baseDir . '".');
        } elseif ($rel === '') {
            if (!$allowBaseDirPath) {
                throw new \Exception('Path relativize failed, basedir path "' . $p . '" not allowed.');
            } else {
                $results[$rel] = './';
            }
        } else {
            $results[$rel] = $p;
        }
    }
    return $results;
}

function getDirContentsWithRelKeys(string $dir, int $onlyFiles = 0, string $excludeRegex = '~/\.git/~', int $maxDepth = -1): array {
    return updateKeysWithRelPath(getDirContents($dir, $onlyFiles, $excludeRegex, $maxDepth), $dir);
}

This version solves/improves:

1. warnings from realpath when PHP open_basedir does not cover the .. directory.
2. does not use reference for the result array
3. allows to exclude directories and files
4. allows to list files/directories only
5. allows to limit the search depth
6. it always sort output with directories first (so directories can be removed/emptied in reverse order)
7. allows to get paths with relative keys
8. heavy optimized for hundred of thousands or even milions of files
9. write for more in the comments :)

Examples:

// list only `*.php` files and skip .git/ and the current file
$onlyPhpFilesExcludeRegex = '~/\.git/|(?