From 25381a2809d43348ed2ad0be0d45d433238c096e Mon Sep 17 00:00:00 2001
From: Christian Flothmann <christian.flothmann@sensiolabs.de>
Date: Thu, 25 May 2017 11:59:42 +0200
Subject: [PATCH] [Filesystem] improve error handling in lock()

---
 .../Component/Filesystem/LockHandler.php      |  9 +++--
 .../Filesystem/Tests/LockHandlerTest.php      | 40 +++++++++++++++++++
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/Symfony/Component/Filesystem/LockHandler.php b/src/Symfony/Component/Filesystem/LockHandler.php
index 67e6f8f522..3496faae21 100644
--- a/src/Symfony/Component/Filesystem/LockHandler.php
+++ b/src/Symfony/Component/Filesystem/LockHandler.php
@@ -68,8 +68,12 @@ class LockHandler
             return true;
         }
 
+        $error = null;
+
         // Silence error reporting
-        set_error_handler(function () {});
+        set_error_handler(function ($errno, $msg) use (&$error) {
+            $error = $msg;
+        });
 
         if (!$this->handle = fopen($this->file, 'r')) {
             if ($this->handle = fopen($this->file, 'x')) {
@@ -82,8 +86,7 @@ class LockHandler
         restore_error_handler();
 
         if (!$this->handle) {
-            $error = error_get_last();
-            throw new IOException($error['message'], 0, null, $this->file);
+            throw new IOException($error, 0, null, $this->file);
         }
 
         // On Windows, even if PHP doc says the contrary, LOCK_NB works, see
diff --git a/src/Symfony/Component/Filesystem/Tests/LockHandlerTest.php b/src/Symfony/Component/Filesystem/Tests/LockHandlerTest.php
index 1fc2ebc0c1..0791cebc69 100644
--- a/src/Symfony/Component/Filesystem/Tests/LockHandlerTest.php
+++ b/src/Symfony/Component/Filesystem/Tests/LockHandlerTest.php
@@ -12,6 +12,8 @@
 namespace Symfony\Component\Filesystem\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Filesystem\Exception\IOException;
+use Symfony\Component\Filesystem\Filesystem;
 use Symfony\Component\Filesystem\LockHandler;
 
 class LockHandlerTest extends TestCase
@@ -40,6 +42,44 @@ class LockHandlerTest extends TestCase
         new LockHandler('lock', '/');
     }
 
+    public function testErrorHandlingInLockIfLockPathBecomesUnwritable()
+    {
+        // skip test on Windows; PHP can't easily set file as unreadable on Windows
+        if ('\\' === DIRECTORY_SEPARATOR) {
+            $this->markTestSkipped('This test cannot run on Windows.');
+        }
+
+        $lockPath = sys_get_temp_dir().'/'.uniqid();
+        $e = null;
+        $wrongMessage = null;
+
+        try {
+            mkdir($lockPath);
+
+            $lockHandler = new LockHandler('lock', $lockPath);
+
+            chmod($lockPath, 0444);
+
+            $lockHandler->lock();
+        } catch (IOException $e) {
+            if (false === strpos($e->getMessage(), 'Permission denied')) {
+                $wrongMessage = $e->getMessage();
+            } else {
+                $this->addToAssertionCount(1);
+            }
+        } catch (\Exception $e) {
+        } catch (\Throwable $e) {
+        }
+
+        if (is_dir($lockPath)) {
+            $fs = new Filesystem();
+            $fs->remove($lockPath);
+        }
+
+        $this->assertInstanceOf('Symfony\Component\Filesystem\Exception\IOException', $e, sprintf('Expected IOException to be thrown, got %s instead.', get_class($e)));
+        $this->assertNull($wrongMessage, sprintf('Expected exception message to contain "Permission denied", got "%s" instead.', $wrongMessage));
+    }
+
     public function testConstructSanitizeName()
     {
         $lock = new LockHandler('<?php echo "% hello word ! %" ?>');