From 3d5f4757035f25e986b931637d829368eb375efe Mon Sep 17 00:00:00 2001
From: "Attia A. Ahmed" <attia.a.ahmed@gmail.com>
Date: Fri, 21 Jul 2023 11:58:54 +0300
Subject: [PATCH] Fix broken junctions leading to installation failure on
 Windows (#11550)

---
 src/Composer/Util/Filesystem.php            |  6 ++++
 tests/Composer/Test/Util/FilesystemTest.php | 33 +++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/src/Composer/Util/Filesystem.php b/src/Composer/Util/Filesystem.php
index 91b1cbe48..04920d775 100644
--- a/src/Composer/Util/Filesystem.php
+++ b/src/Composer/Util/Filesystem.php
@@ -814,6 +814,12 @@ class Filesystem
         if (!is_dir($target)) {
             throw new IOException(sprintf('Cannot junction to "%s" as it is not a directory.', $target), 0, null, $target);
         }
+
+        // Removing any previously junction to ensure clean execution.
+        if (!is_dir($junction) || $this->isJunction($junction)) {
+            @rmdir($junction);
+        }
+
         $cmd = sprintf(
             'mklink /J %s %s',
             ProcessExecutor::escape(str_replace('/', DIRECTORY_SEPARATOR, $junction)),
diff --git a/tests/Composer/Test/Util/FilesystemTest.php b/tests/Composer/Test/Util/FilesystemTest.php
index bdf6b7f16..9a991e4d9 100644
--- a/tests/Composer/Test/Util/FilesystemTest.php
+++ b/tests/Composer/Test/Util/FilesystemTest.php
@@ -12,6 +12,7 @@
 
 namespace Composer\Test\Util;
 
+use Composer\Util\Platform;
 use Composer\Util\Filesystem;
 use Composer\Test\TestCase;
 
@@ -327,6 +328,38 @@ class FilesystemTest extends TestCase
         $this->assertFalse(is_dir($junction), $junction . ' is not a directory');
     }
 
+    public function testOverrideJunctions()
+    {
+        if (!Platform::isWindows()) {
+            $this->markTestSkipped('Only runs on windows');
+        }
+
+        @mkdir($this->workingDir.'/real/nesting/testing', 0777, true);
+        $fs = new Filesystem();
+
+        $old_target = $this->workingDir.'/real/nesting/testing';
+        $target = $this->workingDir.'/real/../real/nesting';
+        $junction = $this->workingDir.'/junction';
+
+        // Override non-broken junction
+        $fs->junction($old_target, $junction);
+        $fs->junction($target, $junction);
+
+        $this->assertTrue($fs->isJunction($junction), $junction.': is a junction');
+        $this->assertTrue($fs->isJunction($target.'/../../junction'), $target.'/../../junction: is a junction');
+
+        //Remove junction
+        $this->assertTrue($fs->removeJunction($junction), $junction . ' has been removed');
+
+        // Override broken junction
+        $fs->junction($old_target, $junction);
+        $fs->removeDirectory($old_target);
+        $fs->junction($target, $junction);
+
+        $this->assertTrue($fs->isJunction($junction), $junction.': is a junction');
+        $this->assertTrue($fs->isJunction($target.'/../../junction'), $target.'/../../junction: is a junction');
+    }
+
     public function testCopy()
     {
         @mkdir($this->workingDir . '/foo/bar', 0777, true);