Don't run loop automatically when an uncaught exceptions occurs

src/Loop.php

@@ -41,6 +41,12 @@ public static function get()
         });
 
         register_shutdown_function(function () use ($loop, &$hasRun) {
+            // Don't run if we're coming from a fatal error (uncaught exception).
+            $error = error_get_last();
+            if ((isset($error['type']) ? $error['type'] : 0) & (E_ERROR | E_CORE_ERROR | E_COMPILE_ERROR | E_USER_ERROR | E_RECOVERABLE_ERROR)) {
+                return;
+            }
+
             if (!$hasRun) {
                 $loop->run();
             }

tests/BinTest.php

@@ -36,4 +36,22 @@ public function testExecuteExampleWithExplicitLoopRunAndStopRunsLoopAndExecutesT
 
         $this->assertEquals('abc', $output);
     }
+
+    public function testExecuteExampleWithUncaughtExceptionShouldNotRunLoop()
+    {
+        $time = microtime(true);
+        exec(escapeshellarg(PHP_BINARY) . ' 11-uncaught.php 2>/dev/null');
+        $time = microtime(true) - $time;
+
+        $this->assertLessThan(1.0, $time);
+    }
+
+    public function testExecuteExampleWithUndefinedVariableShouldNotRunLoop()
+    {
+        $time = microtime(true);
+        exec(escapeshellarg(PHP_BINARY) . ' 12-undefined.php 2>/dev/null');
+        $time = microtime(true) - $time;
+
+        $this->assertLessThan(1.0, $time);
+    }
 }

tests/bin/11-uncaught.php

@@ -0,0 +1,11 @@
+<?php
+
+use React\EventLoop\Loop;
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+Loop::addTimer(10.0, function () {
+    echo 'never';
+});
+
+throw new RuntimeException();

tests/bin/12-undefined.php

@@ -0,0 +1,11 @@
+<?php
+
+use React\EventLoop\Loop;
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+Loop::get()->addTimer(10.0, function () {
+    echo 'never';
+});
+
+$undefined->foo('bar');