Add defer()

lib/functions.php

@@ -75,6 +75,18 @@ namespace Amp
         return static fn(mixed ...$args): Promise => async($callback, ...$args);
     }
 
+    /**
+     * Executes the given callback in a new green thread using {@see async()}, forwarding any exceptions thrown to
+     * the event loop error handler using {@see Promise\rethrow()}.
+     *
+     * @param callable(mixed ...$args):void $callback
+     * @param mixed    ...$args
+     */
+    function defer(callable $callback, mixed ...$args): void
+    {
+        Promise\rethrow(async($callback, ...$args));
+    }
+
     /**
      * Returns a new function that wraps $callback in a promise/coroutine-aware function that automatically runs
      * Generators as coroutines. The returned function always returns a promise when invoked. Errors have to be handled
@@ -156,7 +168,7 @@ namespace Amp
      *
      * @deprecated No longer necessary with ext-fiber
      */
-    function call(callable $callback, ...$args): Promise
+    function call(callable $callback, mixed ...$args): Promise
     {
         try {
             $result = $callback(...$args);
@@ -190,7 +202,7 @@ namespace Amp
      *
      * @deprecated No longer necessary with ext-fiber
      */
-    function asyncCall(callable $callback, ...$args): void
+    function asyncCall(callable $callback, mixed ...$args): void
     {
         Promise\rethrow(call($callback, ...$args));
     }
@@ -203,6 +215,14 @@ namespace Amp
         return new Delayed($milliseconds);
     }
 
+    /**
+     * Async sleep for the specified number of milliseconds.
+     */
+    function sleep(int $milliseconds): void
+    {
+        await(delay($milliseconds));
+    }
+
     /**
      * Returns the current time relative to an arbitrary point in time.
      *
@@ -212,14 +232,6 @@ namespace Amp
     {
         return Internal\getCurrentTime();
     }
-
-    /**
-     * Async sleep for the specified number of milliseconds.
-     */
-    function sleep(int $milliseconds): void
-    {
-        await(delay($milliseconds));
-    }
 }
 
 namespace Amp\Promise
@@ -249,7 +261,7 @@ namespace Amp\Promise
      * @throws \TypeError If $promise is not an instance of \Amp\Promise or \React\Promise\PromiseInterface.
      *
      */
-    function rethrow(Promise|ReactPromise $promise)
+    function rethrow(Promise|ReactPromise $promise): void
     {
         if (!$promise instanceof Promise) {
             $promise = adapt($promise);
@@ -629,17 +641,15 @@ namespace Amp\Promise
      *
      * @return Promise
      */
-    function wrap($promise, callable $callback): Promise
+    function wrap(Promise|ReactPromise $promise, callable $callback): Promise
     {
         if ($promise instanceof ReactPromise) {
             $promise = adapt($promise);
-        } elseif (!$promise instanceof Promise) {
-            throw createTypeError([Promise::class, ReactPromise::class], $promise);
         }
 
-        $deferred = new Deferred();
+        $deferred = new Deferred;
 
-        $promise->onResolve(static function (\Throwable $exception = null, $result) use ($deferred, $callback) {
+        $promise->onResolve(static function (?\Throwable $exception, mixed $result) use ($deferred, $callback): void {
             try {
                 $result = $callback($exception, $result);
             } catch (\Throwable $exception) {

test/DeferTest.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Amp\Test;
+
+use Amp\Loop;
+use Amp\PHPUnit\AsyncTestCase;
+use Amp\PHPUnit\TestException;
+use function Amp\defer;
+use function Amp\sleep;
+
+class DeferTest extends AsyncTestCase
+{
+    public function testExceptionsRethrownToLoopHandler(): void
+    {
+        Loop::setErrorHandler(function (\Throwable $exception) use (&$reason): void {
+            $reason = $exception;
+        });
+
+        $exception = new TestException;
+
+        defer(function () use ($exception): void {
+            throw $exception;
+        });
+
+        sleep(0); // Tick event loop.
+
+        $this->assertSame($exception, $reason);
+    }
+}