Merge pull request #229 from clue-labs/queue-fibers

Continue internal `Queue` execution also after fiber is suspended

Author: WyriHaximus

src/Internal/Queue.php

@@ -19,11 +19,10 @@ public function enqueue(callable $task): void
     private function drain(): void
     {
         for ($i = \key($this->queue); isset($this->queue[$i]); $i++) {
-            try {
-                ($this->queue[$i])();
-            } finally {
-                unset($this->queue[$i]);
-            }
+            $task = $this->queue[$i];
+            unset($this->queue[$i]);
+
+            $task();
         }
 
         $this->queue = [];

tests/Internal/QueueTest.php

@@ -30,6 +30,27 @@ public function executesNestedEnqueuedTasks()
         $queue->enqueue($task);
     }
 
+    /**
+     * @test
+     * @requires PHP 8.1
+     */
+    public function executesFollowingTasksIfPriorTaskSuspendsFiber()
+    {
+        $queue = new Queue();
+
+        $fiber = new \Fiber(function () use ($queue) {
+            $queue->enqueue(function () {
+                \Fiber::suspend(2);
+            });
+            return 1;
+        });
+
+        $ret = $fiber->start();
+        $this->assertEquals(2, $ret);
+
+        $queue->enqueue($this->expectCallableOnce());
+    }
+
     /**
      * @test
      */

tests/PromiseTest/PromiseFulfilledTestTrait.php

@@ -184,6 +184,33 @@ public function thenShouldSwitchFromCallbacksToErrbacksWhenCallbackThrows()
             );
     }
 
+    /**
+     * @test
+     * @requires PHP 8.1
+     */
+    public function thenShouldContinueToExecuteCallbacksWhenPriorCallbackSuspendsFiber()
+    {
+        $adapter = $this->getPromiseTestAdapter();
+        $adapter->resolve(42);
+
+        $fiber = new \Fiber(function () use ($adapter) {
+            $adapter->promise()->then(function (int $value) {
+                \Fiber::suspend($value);
+            });
+        });
+
+        $ret = $fiber->start();
+        $this->assertEquals(42, $ret);
+
+        $mock = $this->createCallableMock();
+        $mock
+            ->expects($this->once())
+            ->method('__invoke')
+            ->with($this->identicalTo(42));
+
+        $adapter->promise()->then($mock);
+    }
+
     /** @test */
     public function cancelShouldReturnNullForFulfilledPromise()
     {