Keep absolute path repos symlinks absolute, fixes #8700

src/Composer/Downloader/PathDownloader.php

@@ -75,7 +75,7 @@ class PathDownloader extends FileDownloader implements VcsCapableDownloaderInter
         }
 
         // Get the transport options with default values
-        $transportOptions = $package->getTransportOptions() + array('symlink' => null);
+        $transportOptions = $package->getTransportOptions() + array('symlink' => null, 'relative' => true);
 
         // When symlink transport option is null, both symlink and mirror are allowed
         $currentStrategy = self::STRATEGY_SYMLINK;
@@ -126,7 +126,11 @@ class PathDownloader extends FileDownloader implements VcsCapableDownloaderInter
                     $shortestPath = $this->filesystem->findShortestPath($absolutePath, $realUrl);
                     $path = rtrim($path, "/");
                     $this->io->writeError(sprintf('Symlinking from %s', $url), false);
-                    $fileSystem->symlink($shortestPath, $path);
+                    if ($transportOptions['relative']) {
+                        $fileSystem->symlink($shortestPath, $path);
+                    } else {
+                        $fileSystem->symlink($absolutePath, $path);
+                    }
                 }
             } catch (IOException $e) {
                 if (in_array(self::STRATEGY_MIRROR, $allowedStrategies)) {

src/Composer/Repository/PathRepository.php

@@ -20,6 +20,7 @@ use Composer\Package\Version\VersionGuesser;
 use Composer\Package\Version\VersionParser;
 use Composer\Util\Platform;
 use Composer\Util\ProcessExecutor;
+use Composer\Util\Filesystem;
 
 /**
  * This repository allows installing local packages that are not necessarily under their own VCS.
@@ -107,6 +108,10 @@ class PathRepository extends ArrayRepository implements ConfigurableRepositoryIn
         $this->versionGuesser = new VersionGuesser($config, $this->process, new VersionParser());
         $this->repoConfig = $repoConfig;
         $this->options = isset($repoConfig['options']) ? $repoConfig['options'] : array();
+        if (!isset($this->options['relative'])) {
+            $filesystem = new Filesystem();
+            $this->options['relative'] = !$filesystem->isAbsolutePath($this->url);
+        }
 
         parent::__construct();
     }