[3.x] Improve PHP 8.4+ support by avoiding implicitly nullable types

This changeset improves PHP 8.4+ support by avoiding implicitly nullable types as discussed in reactphp/promise#260.

I'm planning to add native types to the public API and introduce PHPStan in follow-up PRs.

Once merged, we should apply similar changes to all our upcoming v3 components. On top of this, we should backport similar changes to the v1 branch.

Builds on top of reactphp#182, reactphp#222 and reactphp/promise#260

src/Query/TcpTransportExecutor.php

@@ -135,7 +135,7 @@ class TcpTransportExecutor implements ExecutorInterface
      * @param string         $nameserver
      * @param ?LoopInterface $loop
      */
-    public function __construct($nameserver, LoopInterface $loop = null)
+    public function __construct($nameserver, ?LoopInterface $loop = null)
     {
         if (\strpos($nameserver, '[') === false && \substr_count($nameserver, ':') >= 2 && \strpos($nameserver, '://') === false) {
             // several colons, but not enclosed in square brackets => enclose IPv6 address in square brackets

src/Query/TimeoutExecutor.php

@@ -12,7 +12,12 @@ final class TimeoutExecutor implements ExecutorInterface
     private $loop;
     private $timeout;
 
-    public function __construct(ExecutorInterface $executor, $timeout, LoopInterface $loop = null)
+    /**
+     * @param ?ExecutorInterface $executor
+     * @param float|int $timeout
+     * @param ?LoopInterface $loop
+     */
+    public function __construct(?ExecutorInterface $executor, $timeout, ?LoopInterface $loop = null)
     {
         $this->executor = $executor;
         $this->loop = $loop ?: Loop::get();

src/Query/UdpTransportExecutor.php

@@ -99,7 +99,7 @@ final class UdpTransportExecutor implements ExecutorInterface
      * @param string         $nameserver
      * @param ?LoopInterface $loop
      */
-    public function __construct($nameserver, LoopInterface $loop = null)
+    public function __construct($nameserver, ?LoopInterface $loop = null)
     {
         if (\strpos($nameserver, '[') === false && \substr_count($nameserver, ':') >= 2 && \strpos($nameserver, '://') === false) {
             // several colons, but not enclosed in square brackets => enclose IPv6 address in square brackets

src/Resolver/Factory.php

@@ -36,7 +36,7 @@ final class Factory
      * @throws \InvalidArgumentException for invalid DNS server address
      * @throws \UnderflowException when given DNS Config object has an empty list of nameservers
      */
-    public function create($config, LoopInterface $loop = null)
+    public function create($config, ?LoopInterface $loop = null)
     {
         $executor = $this->decorateHostsFileExecutor($this->createExecutor($config, $loop ?: Loop::get()));
 
@@ -59,7 +59,7 @@ public function create($config, LoopInterface $loop = null)
      * @throws \InvalidArgumentException for invalid DNS server address
      * @throws \UnderflowException when given DNS Config object has an empty list of nameservers
      */
-    public function createCached($config, LoopInterface $loop = null, CacheInterface $cache = null)
+    public function createCached($config, ?LoopInterface $loop = null, ?CacheInterface $cache = null)
     {
         // default to keeping maximum of 256 responses in cache unless explicitly given
         if (!($cache instanceof CacheInterface)) {