Require PHP 8.1 and use features (#55)

.github/workflows/ci.yml

@@ -11,9 +11,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - operating-system: 'ubuntu-latest'
-            php-version: '8.0'
-            composer-flags: '--ignore-platform-req=php'
           - operating-system: 'ubuntu-latest'
             php-version: '8.1'
             composer-flags: '--ignore-platform-req=php'
@@ -40,7 +37,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php-version }}
-          extensions: fiber-amphp/ext-fiber@master, uv-amphp/ext-uv@master, ev-beta, event, :xdebug
+          extensions: uv-amphp/ext-uv@master, ev-beta, event, :xdebug
 
       - name: Get Composer cache directory
         id: composer-cache

README.md

@@ -21,8 +21,7 @@ Different (strongly) opinionated libraries can be built on top of it and both Am
 ## Installation
 
 It may surprise people to learn that the PHP standard library already has everything we need to write event-driven and non-blocking applications.
-This package can be installed as a [Composer](https://getcomposer.org/) dependency on PHP 8 and later.
-PHP 8.1 ships with fibers built-in, but users on PHP 8.0 can install [`ext-fiber`](https://github.com/amphp/ext-fiber) with almost identical behavior.
+This package can be installed as a [Composer](https://getcomposer.org/) dependency on PHP 8.1 and later.
 
 ```bash
 composer require revolt/event-loop

composer.json

@@ -30,7 +30,7 @@
         }
     ],
     "require": {
-        "php": ">=8.0.7"
+        "php": ">=8.1"
     },
     "require-dev": {
         "ext-json": "*",

src/EventLoop/Driver/EvDriver.php

@@ -27,11 +27,11 @@ public static function isSupported(): bool
     /** @var \EvWatcher[] */
     private array $events = [];
 
-    private \Closure $ioCallback;
+    private readonly \Closure $ioCallback;
 
-    private \Closure $timerCallback;
+    private readonly \Closure $timerCallback;
 
-    private \Closure $signalCallback;
+    private readonly \Closure $signalCallback;
 
     /** @var \EvSignal[] */
     private array $signals = [];

src/EventLoop/Driver/EventDriver.php

@@ -25,9 +25,9 @@ public static function isSupported(): bool
     private \EventBase $handle;
     /** @var \Event[] */
     private array $events = [];
-    private \Closure $ioCallback;
-    private \Closure $timerCallback;
-    private \Closure $signalCallback;
+    private readonly \Closure $ioCallback;
+    private readonly \Closure $timerCallback;
+    private readonly \Closure $signalCallback;
     private array $signals = [];
 
     public function __construct()

src/EventLoop/Driver/StreamSelectDriver.php

@@ -27,17 +27,17 @@ final class StreamSelectDriver extends AbstractDriver
     /** @var StreamWritableCallback[][] */
     private array $writeCallbacks = [];
 
-    private TimerQueue $timerQueue;
+    private readonly TimerQueue $timerQueue;
 
     /** @var SignalCallback[][] */
     private array $signalCallbacks = [];
 
     /** @var \SplQueue<int> */
-    private \SplQueue $signalQueue;
+    private readonly \SplQueue $signalQueue;
 
     private bool $signalHandling;
 
-    private \Closure $streamSelectErrorHandler;
+    private readonly \Closure $streamSelectErrorHandler;
 
     private bool $streamSelectIgnoreResult = false;
 
@@ -166,12 +166,19 @@ protected function activate(array $callbacks): void
                 $this->timerQueue->insert($callback);
             } elseif ($callback instanceof SignalCallback) {
                 if (!isset($this->signalCallbacks[$callback->signal])) {
-                    if (!@\pcntl_signal($callback->signal, \Closure::fromCallable([$this, 'handleSignal']))) {
-                        $message = "Failed to register signal handler";
-                        if ($error = \error_get_last()) {
-                            $message .= \sprintf("; Errno: %d; %s", $error["type"], $error["message"]);
-                        }
-                        throw new \Error($message);
+                    \set_error_handler(static function (int $errno, string $errstr): bool {
+                        throw new UnsupportedFeatureException(
+                            \sprintf("Failed to register signal handler; Errno: %d; %s", $errno, $errstr)
+                        );
+                    });
+
+                    // Avoid bug in Psalm handling of first-class callables by assigning to a temp variable.
+                    $handler = $this->handleSignal(...);
+
+                    try {
+                        \pcntl_signal($callback->signal, $handler);
+                    } finally {
+                        \restore_error_handler();
                     }
                 }
 
@@ -209,7 +216,12 @@ protected function deactivate(DriverCallback $callback): void
 
                 if (empty($this->signalCallbacks[$callback->signal])) {
                     unset($this->signalCallbacks[$callback->signal]);
-                    @\pcntl_signal($callback->signal, \SIG_DFL);
+                    \set_error_handler(static fn () => true);
+                    try {
+                        \pcntl_signal($callback->signal, \SIG_DFL);
+                    } finally {
+                        \restore_error_handler();
+                    }
                 }
             }
         } else {

src/EventLoop/Driver/TracingDriver.php

@@ -8,7 +8,7 @@
 
 final class TracingDriver implements Driver
 {
-    private Driver $driver;
+    private readonly Driver $driver;
 
     /** @var true[] */
     private array $enabledCallbacks = [];

src/EventLoop/Driver/UvDriver.php

@@ -25,9 +25,9 @@ public static function isSupported(): bool
     private array $callbacks = [];
     /** @var resource[] */
     private array $streams = [];
-    private \Closure $ioCallback;
-    private \Closure $timerCallback;
-    private \Closure $signalCallback;
+    private readonly \Closure $ioCallback;
+    private readonly \Closure $timerCallback;
+    private readonly \Closure $signalCallback;
 
     public function __construct()
     {

src/EventLoop/FiberLocal.php

@@ -47,7 +47,7 @@ private static function getFiberStorage(): \WeakMap
     /**
      * @param \Closure():T $initializer
      */
-    public function __construct(private \Closure $initializer)
+    public function __construct(private readonly \Closure $initializer)
     {
     }
 

src/EventLoop/Internal/AbstractDriver.php

@@ -20,31 +20,6 @@
  */
 abstract class AbstractDriver implements Driver
 {
-    private static function checkFiberSupport(): void
-    {
-        if (!\class_exists(\Fiber::class, false)) {
-            if (\PHP_VERSION_ID < 80000) {
-                throw new \Error(
-                    "revolt/event-loop requires fibers to be available. " .
-                    "You're currently running PHP " . \PHP_VERSION . " without fiber support. " .
-                    "Please upgrade to PHP 8.1 or upgrade to PHP 8.0 and install ext-fiber from https://github.com/amphp/ext-fiber."
-                );
-            }
-
-            if (\PHP_VERSION_ID < 80100) {
-                throw new \Error(
-                    "revolt/event-loop requires fibers to be available. " .
-                    "You're currently running PHP " . \PHP_VERSION . " without fiber support. " .
-                    "Please upgrade to PHP 8.1 or install ext-fiber from https://github.com/amphp/ext-fiber."
-                );
-            }
-
-            throw new \Error(
-                "revolt/event-loop requires PHP 8.1 or ext-fiber. You are currently running PHP " . \PHP_VERSION . "."
-            );
-        }
-    }
-
     /** @var string Next callback identifier. */
     private string $nextId = "a";
 
@@ -66,17 +41,17 @@ private static function checkFiberSupport(): void
     private ?\Closure $errorHandler = null;
     private ?\Closure $interrupt = null;
 
-    private \Closure $interruptCallback;
-    private \Closure $queueCallback;
-    private \Closure $runCallback;
+    private readonly \Closure $interruptCallback;
+    private readonly \Closure $queueCallback;
+    private readonly \Closure $runCallback;
 
-    private \stdClass $internalSuspensionMarker;
+    private readonly \stdClass $internalSuspensionMarker;
 
     /** @var \SplQueue<array{\Closure, array}> */
-    private \SplQueue $microtaskQueue;
+    private readonly \SplQueue $microtaskQueue;
 
     /** @var \SplQueue<DriverCallback> */
-    private \SplQueue $callbackQueue;
+    private readonly \SplQueue $callbackQueue;
 
     private bool $idle = false;
     private bool $stopped = false;
@@ -85,8 +60,6 @@ private static function checkFiberSupport(): void
 
     public function __construct()
     {
-        self::checkFiberSupport();
-
         $this->suspensions = new \WeakMap();
 
         $this->internalSuspensionMarker = new \stdClass();
@@ -98,8 +71,8 @@ public function __construct()
         $this->createErrorCallback();
 
         /** @psalm-suppress InvalidArgument */
-        $this->interruptCallback = \Closure::fromCallable([$this, 'setInterrupt']);
-        $this->queueCallback = \Closure::fromCallable([$this, 'queue']);
+        $this->interruptCallback = $this->setInterrupt(...);
+        $this->queueCallback = $this->queue(...);
         $this->runCallback = function () {
             if ($this->fiber->isTerminated()) {
                 $this->createLoopFiber();

src/EventLoop/Internal/DriverCallback.php

@@ -13,32 +13,25 @@ abstract class DriverCallback
 
     public bool $referenced = true;
 
-    public \Closure $closure;
-
     public function __construct(
-        public string $id,
-        \Closure $closure
+        public readonly string $id,
+        public readonly \Closure $closure
     ) {
-        $this->closure = $closure;
     }
 
     /**
      * @param string $property
-     *
-     * @psalm-return no-return
      */
-    public function __get(string $property): void
+    public function __get(string $property): never
     {
         throw new \Error("Unknown property '${property}'");
     }
 
     /**
      * @param string $property
      * @param mixed  $value
-     *
-     * @psalm-return no-return
      */
-    public function __set(string $property, mixed $value): void
+    public function __set(string $property, mixed $value): never
     {
         throw new \Error("Unknown property '${property}'");
     }

src/EventLoop/Internal/DriverSuspension.php

@@ -15,19 +15,19 @@ final class DriverSuspension implements Suspension
     private ?\Fiber $suspendedFiber = null;
 
     /** @var \WeakReference<\Fiber>|null */
-    private ?\WeakReference $fiberRef;
+    private readonly ?\WeakReference $fiberRef;
 
     private ?\FiberError $fiberError = null;
 
-    private \Closure $run;
+    private readonly \Closure $run;
 
-    private \Closure $queue;
+    private readonly \Closure $queue;
 
-    private \Closure $interrupt;
+    private readonly \Closure $interrupt;
 
     private bool $pending = false;
 
-    private \WeakReference $suspensions;
+    private readonly \WeakReference $suspensions;
 
     /**
      * @param \Closure $run
@@ -59,7 +59,7 @@ public function resume(mixed $value = null): void
         $fiber = $this->fiberRef?->get();
 
         if ($fiber) {
-            ($this->queue)(\Closure::fromCallable([$fiber, 'resume']), $value);
+            ($this->queue)($fiber->resume(...), $value);
         } else {
             // Suspend event loop fiber to {main}.
             ($this->interrupt)(static fn () => $value);
@@ -139,7 +139,7 @@ public function throw(\Throwable $throwable): void
         $fiber = $this->fiberRef?->get();
 
         if ($fiber) {
-            ($this->queue)(\Closure::fromCallable([$fiber, 'throw']), $throwable);
+            ($this->queue)($fiber->throw(...), $throwable);
         } else {
             // Suspend event loop fiber to {main}.
             ($this->interrupt)(static fn () => throw $throwable);

src/EventLoop/Internal/SignalCallback.php

@@ -8,7 +8,7 @@ final class SignalCallback extends DriverCallback
     public function __construct(
         string $id,
         \Closure $closure,
-        public int $signal
+        public readonly int $signal
     ) {
         parent::__construct($id, $closure);
     }

src/EventLoop/Internal/StreamCallback.php

@@ -11,7 +11,7 @@ abstract class StreamCallback extends DriverCallback
     public function __construct(
         string $id,
         \Closure $closure,
-        public mixed $stream
+        public readonly mixed $stream
     ) {
         parent::__construct($id, $closure);
     }

src/EventLoop/Internal/TimerCallback.php

@@ -7,10 +7,10 @@ final class TimerCallback extends DriverCallback
 {
     public function __construct(
         string $id,
-        public float $interval,
+        public readonly float $interval,
         \Closure $callback,
         public float $expiration,
-        public bool $repeat = false
+        public readonly bool $repeat = false
     ) {
         parent::__construct($id, $callback);
     }

src/EventLoop/InvalidCallbackError.php

@@ -32,10 +32,10 @@ public static function invalidIdentifier(string $callbackId): self
     }
 
     /** @var string */
-    private string $rawMessage;
+    private readonly string $rawMessage;
 
     /** @var string */
-    private string $callbackId;
+    private readonly string $callbackId;
 
     /** @var string[] */
     private array $info = [];