// Created on savesnippets.com · https://savesnippets.com/bpEnsbruuu7Pre
<?php
function parseQueryRaw(string $query): array {
    $out = [];
    foreach (explode('&', $query) as $pair) {
        if ($pair === '') continue;
        [$k, $v] = array_pad(explode('=', $pair, 2), 2, '');
        $out[urldecode($k)] = urldecode($v);
    }
    return $out;
}

print_r(parseQueryRaw('user.id=42&user.name=Alice&path=/foo'));
// [ "user.id" => "42", "user.name" => "Alice", "path" => "/foo" ]
//
// (parse_str would have mangled "user.id" → "user_id")