Fix killing a thread; avoid issues with signals

src/Forking/Fork.php

@@ -158,14 +158,9 @@ class Fork implements ContextInterface
             case 0: // Child
                 // @codeCoverageIgnoreStart
 
-                // We will have a cloned event loop from the parent after forking. The
-                // child context by default is synchronous and uses the parent event
-                // loop, so we need to stop the clone before doing any work in case it
-                // is already running.
-                $loop = Loop\loop();
-                $loop->stop();
-                $loop->reInit();
-                $loop->clear();
+                // Create a new event loop in the fork.
+                $loop = Loop\create(false);
+                Loop\loop($loop);
 
                 $channel = new Channel(new DuplexStream($parent));
                 fclose($child);

src/Threading/Internal/Thread.php

@@ -17,6 +17,8 @@ use Icicle\Socket\Stream\DuplexStream;
  */
 class Thread extends \Thread
 {
+    const KILL_CHECK_FREQUENCY = 0.25;
+
     /**
      * @var callable The function to execute in the thread.
      */
@@ -32,6 +34,11 @@ class Thread extends \Thread
      */
     private $socket;
 
+    /**
+     * @var bool
+     */
+    private $killed = false;
+
     /**
      * Creates a new thread object.
      *
@@ -67,13 +74,32 @@ class Thread extends \Thread
             }
         }
 
+        $loop = Loop\create(false); // Disable signals in thread.
+        Loop\loop($loop);
+
         // At this point, the thread environment has been prepared so begin using the thread.
         $channel = new Channel(new DuplexStream($this->socket));
 
         $coroutine = new Coroutine($this->execute($channel));
         $coroutine->done();
 
-        Loop\run();
+        $timer = $loop->timer(self::KILL_CHECK_FREQUENCY, true, function () use ($loop, $coroutine, $channel) {
+            if ($this->killed) {
+                $loop->stop();
+            }
+        });
+        $timer->unreference();
+
+        $loop->run();
+    }
+
+    /**
+     * Sets a local variable to true so the running event loop can check for a kill signal.
+     */
+    public function kill()
+    {
+        $this->killed = true;
+        parent::kill();
     }
 
     /**

src/Threading/Thread.php

@@ -138,11 +138,13 @@ class Thread implements ContextInterface
      */
     public function kill()
     {
+        if (null === $this->thread) {
+            throw new StatusError('The thread has not been started.');
+        }
+
         $this->close();
 
-        if ($this->isRunning() && !$this->thread->kill()) {
-            throw new ThreadException('Failed to kill the thread.');
-        }
+        $this->thread->kill();
     }
 
     /**