Fix: FlatFileDriver does not notice new messages

.gitignore

@@ -3,3 +3,4 @@ vendor
 phpunit.xml
 coverage
 _build
+.idea

src/Driver/FlatFileDriver.php

@@ -94,17 +94,17 @@ public function popMessage($queueName, $duration = 5)
         $runtime = microtime(true) + $duration;
         $queueDir = $this->getQueueDirectory($queueName);
 
-        $it = new \GlobIterator($queueDir.DIRECTORY_SEPARATOR.'*.job', \FilesystemIterator::KEY_AS_FILENAME);
-        $files = array_keys(iterator_to_array($it));
-
-        natsort($files);
+        $files = $this->getJobFiles($queueName);
 
         while (microtime(true) < $runtime) {
             if ($files) {
                 $id = array_pop($files);
                 if (@rename($queueDir.DIRECTORY_SEPARATOR.$id, $queueDir.DIRECTORY_SEPARATOR.$id.'.proceed')) {
                     return array(file_get_contents($queueDir.DIRECTORY_SEPARATOR.$id.'.proceed'), $id);
                 }
+            } else {
+                // In order to notice that a new message received, update the list.
+                $files = $this->getJobFiles($queueName);
             }
 
             usleep(1000);
@@ -225,4 +225,21 @@ private function getJobFilename($queueName)
 
         return $filename;
     }
+
+    /**
+     * @param string $queueName
+     *
+     * @return string[]
+     */
+    private function getJobFiles($queueName)
+    {
+        $it = new \GlobIterator(
+            $this->getQueueDirectory($queueName) . DIRECTORY_SEPARATOR . '*.job',
+            \FilesystemIterator::KEY_AS_FILENAME
+        );
+        $files = array_keys(iterator_to_array($it));
+        natsort($files);
+
+        return $files;
+    }
 }

tests/Driver/FlatFileDriverTest.php

@@ -92,6 +92,27 @@ public function testPopMessage()
         }
     }
 
+    public function testPopMessageWhichPushedAfterTheInitialCollect()
+    {
+        $this->driver->createQueue('send-newsletter');
+
+        $pid = pcntl_fork();
+
+        if ($pid === -1) {
+            $this->fail('Failed to fork the currently running process: ' . pcntl_strerror(pcntl_get_last_error()));
+        } elseif ($pid === 0) {
+            // Child process pushes a message after the initial collect
+            sleep(5);
+            $this->driver->pushMessage('send-newsletter', 'test');
+            exit;
+        }
+
+        list($message, ) = $this->driver->popMessage('send-newsletter', 10);
+        $this->assertSame('test', $message);
+
+        pcntl_waitpid($pid, $status);
+    }
+
     public function testAcknowledgeMessage()
     {
         $this->driver->createQueue('send-newsletter');