Fix potential issues when operating on destroyed uv handles in shutdown sequence

lib/Loop/UvDriver.php

@@ -260,34 +260,34 @@ class UvDriver extends Driver {
         }
 
         $event = $this->events[$id];
-        $eventId = (int) $event;
+
+        if (!\uv_is_active($event)) {
+            return;
+        }
 
         switch ($watcher->type) {
             case Watcher::READABLE:
             case Watcher::WRITABLE:
                 $flags = 0;
+                $eventId = (int) $event;
                 foreach ($this->watchers[$eventId] as $watcher) {
                     $flags |= $watcher->enabled ? $watcher->type : 0;
                 }
 
                 if ($flags) {
                     \uv_poll_start($event, $flags, $this->ioCallback);
-                } elseif (\uv_is_active($event)) {
+                } else {
                     \uv_poll_stop($event);
                 }
                 break;
 
             case Watcher::DELAY:
             case Watcher::REPEAT:
-                if (\uv_is_active($event)) {
                 \uv_timer_stop($event);
-                }
                 break;
 
             case Watcher::SIGNAL:
-                if (\uv_is_active($event)) {
                 \uv_signal_stop($event);
-                }
                 break;
 
             default:

phpunit.xml.dist

@@ -16,6 +16,9 @@
         <testsuite name="Main">
             <directory>test</directory>
         </testsuite>
+        <testsuite name="PHPT tests">
+            <directory suffix=".phpt">test</directory>
+        </testsuite>
     </testsuites>
     <filter>
         <whitelist>

test/Loop/UvLoopDestructShutdown.phpt

@@ -0,0 +1,30 @@
+--TEST--
+Test order of destruction not interfering with access to UV handles
+--SKIPIF--
+<?php
+extension_loaded("uv") or die("SKIP: ext/uv required for this test");
+?>
+--FILE--
+<?php
+
+include __DIR__.'/../../vendor/autoload.php';
+
+use Amp\Loop;
+
+Loop::run(function() {
+	Loop::setState('test', new class {
+		private $handle;
+		function __construct() {
+			$this->handle = Loop::repeat(10, function() {});
+		}
+		function __destruct() {
+			Loop::cancel($this->handle);
+			print "ok";
+		}
+	});
+	Loop::delay(0, [Loop::class, "stop"]);
+});
+
+?>
+--EXPECT--
+ok