Split up steps on VCS downloaders to allow doing network operations before touching the filesystem on GitDownloader, fixes #7903

src/Composer/Downloader/DownloadManager.php

@@ -165,9 +165,9 @@ class DownloadManager
     /**
      * Downloads package into target dir.
      *
-     * @param PackageInterface $package      package instance
-     * @param string           $targetDir    target dir
-     * @param PackageInterface $prevPackage  previous package instance in case of updates
+     * @param PackageInterface      $package      package instance
+     * @param string                $targetDir    target dir
+     * @param PackageInterface|null $prevPackage  previous package instance in case of updates
      *
      * @return PromiseInterface
      * @throws \InvalidArgumentException if package have no urls to download from
@@ -182,7 +182,7 @@ class DownloadManager
         $io = $this->io;
         $self = $this;
 
-        $download = function ($retry = false) use (&$sources, $io, $package, $self, $targetDir, &$download) {
+        $download = function ($retry = false) use (&$sources, $io, $package, $self, $targetDir, &$download, $prevPackage) {
             $source = array_shift($sources);
             if ($retry) {
                 $io->writeError('    <warning>Now trying to download from ' . $source . '</warning>');
@@ -214,7 +214,7 @@ class DownloadManager
             };
 
             try {
-                $result = $downloader->download($package, $targetDir);
+                $result = $downloader->download($package, $targetDir, $prevPackage);
             } catch (\Exception $e) {
                 return $handleError($e);
             }
@@ -232,12 +232,31 @@ class DownloadManager
         return $download();
     }
 
+    /**
+     * Prepares an operation execution
+     *
+     * @param string                $type         one of install/update/uninstall
+     * @param PackageInterface      $package      package instance
+     * @param string                $targetDir    target dir
+     * @param PackageInterface|null $prevPackage  previous package instance in case of updates
+     *
+     * @return PromiseInterface|null
+     */
+    public function prepare($type, PackageInterface $package, $targetDir, PackageInterface $prevPackage = null)
+    {
+        $downloader = $this->getDownloaderForPackage($package);
+        if ($downloader) {
+            return $downloader->prepare($type, $package, $targetDir, $prevPackage);
+        }
+    }
+
     /**
      * Installs package into target dir.
      *
      * @param PackageInterface $package      package instance
      * @param string           $targetDir    target dir
      *
+     * @return PromiseInterface|null
      * @throws \InvalidArgumentException if package have no urls to download from
      * @throws \RuntimeException
      */
@@ -245,7 +264,7 @@ class DownloadManager
     {
         $downloader = $this->getDownloaderForPackage($package);
         if ($downloader) {
-            $downloader->install($package, $targetDir);
+            return $downloader->install($package, $targetDir);
         }
     }
 
@@ -256,6 +275,7 @@ class DownloadManager
      * @param PackageInterface $target    target package version
      * @param string           $targetDir target dir
      *
+     * @return PromiseInterface|null
      * @throws \InvalidArgumentException if initial package is not installed
      */
     public function update(PackageInterface $initial, PackageInterface $target, $targetDir)
@@ -270,17 +290,14 @@ class DownloadManager
 
         // if we have a downloader present before, but not after, the package became a metapackage and its files should be removed
         if (!$downloader) {
-            $initialDownloader->remove($initial, $targetDir);
-            return;
+            return $initialDownloader->remove($initial, $targetDir);
         }
 
         $initialType = $this->getDownloaderType($initialDownloader);
         $targetType = $this->getDownloaderType($downloader);
         if ($initialType === $targetType) {
             try {
-                $downloader->update($initial, $target, $targetDir);
-
-                return;
+                return $downloader->update($initial, $target, $targetDir);
             } catch (\RuntimeException $e) {
                 if (!$this->io->isInteractive()) {
                     throw $e;
@@ -294,8 +311,15 @@ class DownloadManager
 
         // if downloader type changed, or update failed and user asks for reinstall,
         // we wipe the dir and do a new install instead of updating it
-        $initialDownloader->remove($initial, $targetDir);
-        $this->install($target, $targetDir);
+        $promise = $initialDownloader->remove($initial, $targetDir);
+        if ($promise) {
+            $self = $this;
+            return $promise->then(function ($res) use ($self, $target, $targetDir) {
+                return $self->install($target, $targetDir);
+            });
+        }
+
+        return $this->install($target, $targetDir);
     }
 
     /**
@@ -303,12 +327,32 @@ class DownloadManager
      *
      * @param PackageInterface $package   package instance
      * @param string           $targetDir target dir
+     *
+     * @return PromiseInterface|null
      */
     public function remove(PackageInterface $package, $targetDir)
     {
         $downloader = $this->getDownloaderForPackage($package);
         if ($downloader) {
-            $downloader->remove($package, $targetDir);
+            return $downloader->remove($package, $targetDir);
+        }
+    }
+
+    /**
+     * Cleans up a failed operation
+     *
+     * @param string                $type         one of install/update/uninstall
+     * @param PackageInterface      $package      package instance
+     * @param string                $targetDir    target dir
+     * @param PackageInterface|null $prevPackage  previous package instance in case of updates
+     *
+     * @return PromiseInterface|null
+     */
+    public function cleanup($type, PackageInterface $package, $targetDir, PackageInterface $prevPackage = null)
+    {
+        $downloader = $this->getDownloaderForPackage($package);
+        if ($downloader) {
+            return $downloader->cleanup($type, $package, $targetDir, $prevPackage);
         }
     }
 

src/Composer/Downloader/DownloaderInterface.php

@@ -31,14 +31,30 @@ interface DownloaderInterface
     public function getInstallationSource();
 
     /**
-     * This should do any network-related tasks to prepare for install/update
+     * This should do any network-related tasks to prepare for an upcoming install/update
      *
      * @return PromiseInterface|null
      */
-    public function download(PackageInterface $package, $path);
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null);
 
     /**
-     * Downloads specific package into specific folder.
+     * Do anything that needs to be done between all downloads have been completed and the actual operation is executed
+     *
+     * All packages get first downloaded, then all together prepared, then all together installed/updated/uninstalled. Therefore
+     * for error recovery it is important to avoid failing during install/update/uninstall as much as possible, and risky things or
+     * user prompts should happen in the prepare step rather. In case of failure, cleanup() will be called so that changes can
+     * be undone as much as possible.
+     *
+     * @param  string                $type        one of install/update/uninstall
+     * @param  PackageInterface      $package     package instance
+     * @param  string                $path        download path
+     * @param  PackageInterface      $prevPackage previous package instance in case of an update
+     * @return PromiseInterface|null
+     */
+    public function prepare($type, PackageInterface $package, $path, PackageInterface $prevPackage = null);
+
+    /**
+     * Installs specific package into specific folder.
      *
      * @param PackageInterface $package package instance
      * @param string           $path    download path
@@ -61,4 +77,19 @@ interface DownloaderInterface
      * @param string           $path    download path
      */
     public function remove(PackageInterface $package, $path);
+
+    /**
+     * Do anything to cleanup changes applied in the prepare or install/update/uninstall steps
+     *
+     * Note that cleanup will be called for all packages regardless if they failed an operation or not, to give
+     * all installers a change to cleanup things they did previously, so you need to keep track of changes
+     * applied in the installer/downloader themselves.
+     *
+     * @param  string                $type        one of install/update/uninstall
+     * @param  PackageInterface      $package     package instance
+     * @param  string                $path        download path
+     * @param  PackageInterface      $prevPackage previous package instance in case of an update
+     * @return PromiseInterface|null
+     */
+    public function cleanup($type, PackageInterface $package, $path, PackageInterface $prevPackage = null);
 }

src/Composer/Downloader/FileDownloader.php

@@ -84,7 +84,7 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
     /**
      * {@inheritDoc}
      */
-    public function download(PackageInterface $package, $path, $output = true)
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null, $output = true)
     {
         if (!$package->getDistUrl()) {
             throw new \InvalidArgumentException('The given package is missing url information');
@@ -222,6 +222,20 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
         return $download();
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, $path, PackageInterface $prevPackage = null)
+    {
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, $path, PackageInterface $prevPackage = null)
+    {
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -336,7 +350,7 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
         $e = null;
 
         try {
-            $res = $this->download($package, $targetDir.'_compare', false);
+            $res = $this->download($package, $targetDir.'_compare', null, false);
             $this->httpDownloader->wait();
             $res = $this->install($package, $targetDir.'_compare', false);
 

src/Composer/Downloader/FossilDownloader.php

@@ -23,7 +23,15 @@ class FossilDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doInstall(PackageInterface $package, $path, $url)
+    protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null)
+    {
+
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function doInstall(PackageInterface $package, $path, $url)
     {
         // Ensure we are allowed to use this URL by config
         $this->config->prohibitUrlByConfig($url, $this->io);
@@ -49,7 +57,7 @@ class FossilDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
+    protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
     {
         // Ensure we are allowed to use this URL by config
         $this->config->prohibitUrlByConfig($url, $this->io);

src/Composer/Downloader/GitDownloader.php

@@ -29,6 +29,7 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
     private $hasStashedChanges = false;
     private $hasDiscardedChanges = false;
     private $gitUtil;
+    private $cachedPackages = array();
 
     public function __construct(IOInterface $io, Config $config, ProcessExecutor $process = null, Filesystem $fs = null)
     {
@@ -39,34 +40,49 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
     /**
      * {@inheritDoc}
      */
-    public function doInstall(PackageInterface $package, $path, $url)
+    protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null)
     {
         GitUtil::cleanEnv();
-        $path = $this->normalizePath($path);
-        $cachePath = $this->config->get('cache-vcs-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $url).'/';
-        $ref = $package->getSourceReference();
-        $flag = Platform::isWindows() ? '/D ' : '';
 
-        // --dissociate option is only available since git 2.3.0-rc0
+        $cachePath = $this->config->get('cache-vcs-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $url).'/';
         $gitVersion = $this->gitUtil->getVersion();
-        $msg = "Cloning ".$this->getShortHash($ref);
 
-        $command = 'git clone --no-checkout %url% %path% && cd '.$flag.'%path% && git remote add composer %url% && git fetch composer';
+        // --dissociate option is only available since git 2.3.0-rc0
         if ($gitVersion && version_compare($gitVersion, '2.3.0-rc0', '>=') && Cache::isUsable($cachePath)) {
-            $this->io->writeError('', true, IOInterface::DEBUG);
+            $this->io->writeError("  - Syncing <info>" . $package->getName() . "</info> (<comment>" . $package->getFullPrettyVersion() . "</comment>) into cache");
             $this->io->writeError(sprintf('    Cloning to cache at %s', ProcessExecutor::escape($cachePath)), true, IOInterface::DEBUG);
-            try {
-                $this->gitUtil->fetchRefOrSyncMirror($url, $cachePath, $ref);
-                if (is_dir($cachePath)) {
-                    $command =
-                        'git clone --no-checkout %cachePath% %path% --dissociate --reference %cachePath% '
-                        . '&& cd '.$flag.'%path% '
-                        . '&& git remote set-url origin %url% && git remote add composer %url%';
-                    $msg = "Cloning ".$this->getShortHash($ref).' from cache';
-                }
-            } catch (\RuntimeException $e) {
+            $ref = $package->getSourceReference();
+            if ($this->gitUtil->fetchRefOrSyncMirror($url, $cachePath, $ref) && is_dir($cachePath)) {
+                $this->cachedPackages[$package->getId()][$ref] = true;
             }
         }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function doInstall(PackageInterface $package, $path, $url)
+    {
+        GitUtil::cleanEnv();
+        $path = $this->normalizePath($path);
+        $cachePath = $this->config->get('cache-vcs-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $url).'/';
+        $ref = $package->getSourceReference();
+        $flag = Platform::isWindows() ? '/D ' : '';
+
+        if (!empty($this->cachedPackages[$package->getId()][$ref])) {
+            $msg = "Cloning ".$this->getShortHash($ref).' from cache';
+            $command =
+                'git clone --no-checkout %cachePath% %path% --dissociate --reference %cachePath% '
+                . '&& cd '.$flag.'%path% '
+                . '&& git remote set-url origin %url% && git remote add composer %url%';
+        } else {
+            $msg = "Cloning ".$this->getShortHash($ref);
+            $command = 'git clone --no-checkout %url% %path% && cd '.$flag.'%path% && git remote add composer %url% && git fetch composer';
+            if (getenv('COMPOSER_DISABLE_NETWORK')) {
+                throw new \RuntimeException('The required git reference for '.$package->getName().' is not in cache and network is disabled, aborting');
+            }
+        }
+
         $this->io->writeError($msg);
 
         $commandCallable = function ($url) use ($path, $command, $cachePath) {
@@ -99,30 +115,41 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
     /**
      * {@inheritDoc}
      */
-    public function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
+    protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
     {
         GitUtil::cleanEnv();
+        $path = $this->normalizePath($path);
         if (!$this->hasMetadataRepository($path)) {
             throw new \RuntimeException('The .git directory is missing from '.$path.', see https://getcomposer.org/commit-deps for more information');
         }
 
-        $updateOriginUrl = false;
-        if (
-            0 === $this->process->execute('git remote -v', $output, $path)
-            && preg_match('{^origin\s+(?P<url>\S+)}m', $output, $originMatch)
-            && preg_match('{^composer\s+(?P<url>\S+)}m', $output, $composerMatch)
-        ) {
-            if ($originMatch['url'] === $composerMatch['url'] && $composerMatch['url'] !== $target->getSourceUrl()) {
-                $updateOriginUrl = true;
+        $cachePath = $this->config->get('cache-vcs-dir').'/'.preg_replace('{[^a-z0-9.]}i', '-', $url).'/';
+        $ref = $target->getSourceReference();
+        $flag = Platform::isWindows() ? '/D ' : '';
+
+        if (!empty($this->cachedPackages[$target->getId()][$ref])) {
+            $msg = "Checking out ".$this->getShortHash($ref).' from cache';
+            $command = 'git rev-parse --quiet --verify %ref% || (git remote set-url composer %cachePath% && git fetch composer && git fetch --tags composer); git remote set-url composer %url%';
+        } else {
+            $msg = "Checking out ".$this->getShortHash($ref);
+            $command = 'git remote set-url composer %url% && git rev-parse --quiet --verify %ref% || (git fetch composer && git fetch --tags composer)';
+            if (getenv('COMPOSER_DISABLE_NETWORK')) {
+                throw new \RuntimeException('The required git reference for '.$package->getName().' is not in cache and network is disabled, aborting');
             }
         }
 
-        $ref = $target->getSourceReference();
-        $this->io->writeError(" Checking out ".$this->getShortHash($ref));
-        $command = 'git remote set-url composer %s && git rev-parse --quiet --verify %s || (git fetch composer && git fetch --tags composer)';
+        $this->io->writeError($msg);
 
-        $commandCallable = function ($url) use ($command, $ref) {
-            return sprintf($command, ProcessExecutor::escape($url), ProcessExecutor::escape($ref.'^{commit}'));
+        $commandCallable = function ($url) use ($ref, $command, $cachePath) {
+            return str_replace(
+                array('%url%', '%ref%', '%cachePath%'),
+                array(
+                    ProcessExecutor::escape($url),
+                    ProcessExecutor::escape($ref.'^{commit}'),
+                    ProcessExecutor::escape($cachePath),
+                ),
+                $command
+            );
         };
 
         $this->gitUtil->runCommand($commandCallable, $url, $path);
@@ -133,6 +160,16 @@ class GitDownloader extends VcsDownloader implements DvcsDownloaderInterface
             $target->setSourceReference($newRef);
         }
 
+        $updateOriginUrl = false;
+        if (
+            0 === $this->process->execute('git remote -v', $output, $path)
+            && preg_match('{^origin\s+(?P<url>\S+)}m', $output, $originMatch)
+            && preg_match('{^composer\s+(?P<url>\S+)}m', $output, $composerMatch)
+        ) {
+            if ($originMatch['url'] === $composerMatch['url'] && $composerMatch['url'] !== $target->getSourceUrl()) {
+                $updateOriginUrl = true;
+            }
+        }
         if ($updateOriginUrl) {
             $this->updateOriginUrl($path, $target->getSourceUrl());
         }

src/Composer/Downloader/HgDownloader.php

@@ -24,7 +24,15 @@ class HgDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doInstall(PackageInterface $package, $path, $url)
+    protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null)
+    {
+
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function doInstall(PackageInterface $package, $path, $url)
     {
         $hgUtils = new HgUtils($this->io, $this->config, $this->process);
 
@@ -44,7 +52,7 @@ class HgDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
+    protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
     {
         $hgUtils = new HgUtils($this->io, $this->config, $this->process);
 

src/Composer/Downloader/PathDownloader.php

@@ -37,7 +37,7 @@ class PathDownloader extends FileDownloader implements VcsCapableDownloaderInter
     /**
      * {@inheritdoc}
      */
-    public function download(PackageInterface $package, $path, $output = true)
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null, $output = true)
     {
         $url = $package->getDistUrl();
         $realUrl = realpath($url);

src/Composer/Downloader/PerforceDownloader.php

@@ -24,6 +24,14 @@ class PerforceDownloader extends VcsDownloader
     /** @var Perforce */
     protected $perforce;
 
+    /**
+     * {@inheritDoc}
+     */
+    protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null)
+    {
+
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -76,7 +84,7 @@ class PerforceDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
+    protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
     {
         $this->doInstall($target, $path, $url);
     }

src/Composer/Downloader/SvnDownloader.php

@@ -28,7 +28,15 @@ class SvnDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doInstall(PackageInterface $package, $path, $url)
+    protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null)
+    {
+
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function doInstall(PackageInterface $package, $path, $url)
     {
         SvnUtil::cleanEnv();
         $ref = $package->getSourceReference();
@@ -48,7 +56,7 @@ class SvnDownloader extends VcsDownloader
     /**
      * {@inheritDoc}
      */
-    public function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
+    protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url)
     {
         SvnUtil::cleanEnv();
         $ref = $target->getSourceReference();

src/Composer/Downloader/VcsDownloader.php

@@ -54,9 +54,57 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
     /**
      * {@inheritDoc}
      */
-    public function download(PackageInterface $package, $path)
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null)
     {
-        // noop for now, ideally we would do a git fetch already here, or make sure the cached git repo is synced, etc.
+        if (!$package->getSourceReference()) {
+            throw new \InvalidArgumentException('Package '.$package->getPrettyName().' is missing reference information');
+        }
+
+        $urls = $this->prepareUrls($package->getSourceUrls());
+
+        while ($url = array_shift($urls)) {
+            try {
+                return $this->doDownload($package, $path, $url, $prevPackage);
+            } catch (\Exception $e) {
+                // rethrow phpunit exceptions to avoid hard to debug bug failures
+                if ($e instanceof \PHPUnit_Framework_Exception) {
+                    throw $e;
+                }
+                if ($this->io->isDebug()) {
+                    $this->io->writeError('Failed: ['.get_class($e).'] '.$e->getMessage());
+                } elseif (count($urls)) {
+                    $this->io->writeError('    Failed, trying the next URL');
+                }
+                if (!count($urls)) {
+                    throw $e;
+                }
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, $path, PackageInterface $prevPackage = null)
+    {
+        if ($type === 'update') {
+            $this->cleanChanges($prevPackage, $path, true);
+        } elseif ($type === 'install') {
+            $this->filesystem->emptyDirectory($path);
+        } elseif ($type === 'uninstall') {
+            $this->cleanChanges($package, $path, false);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, $path, PackageInterface $prevPackage = null)
+    {
+        if ($type === 'update') {
+            // TODO keep track of whether prepare was called for this package
+            $this->reapplyChanges($path);
+        }
     }
 
     /**
@@ -69,32 +117,10 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
         }
 
         $this->io->writeError("  - Installing <info>" . $package->getName() . "</info> (<comment>" . $package->getFullPrettyVersion() . "</comment>): ", false);
-        $this->filesystem->emptyDirectory($path);
 
-        $urls = $package->getSourceUrls();
+        $urls = $this->prepareUrls($package->getSourceUrls());
         while ($url = array_shift($urls)) {
             try {
-                if (Filesystem::isLocalPath($url)) {
-                    // realpath() below will not understand
-                    // url that starts with "file://"
-                    $needle = 'file://';
-                    $isFileProtocol = false;
-                    if (0 === strpos($url, $needle)) {
-                        $url = substr($url, strlen($needle));
-                        $isFileProtocol = true;
-                    }
-
-                    // realpath() below will not understand %20 spaces etc.
-                    if (false !== strpos($url, '%')) {
-                        $url = rawurldecode($url);
-                    }
-
-                    $url = realpath($url);
-
-                    if ($isFileProtocol) {
-                        $url = $needle . $url;
-                    }
-                }
                 $this->doInstall($package, $path, $url);
                 break;
             } catch (\Exception $e) {
@@ -141,15 +167,11 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
         $actionName = VersionParser::isUpgrade($initial->getVersion(), $target->getVersion()) ? 'Updating' : 'Downgrading';
         $this->io->writeError("  - " . $actionName . " <info>" . $name . "</info> (<comment>" . $from . "</comment> => <comment>" . $to . "</comment>): ", false);
 
-        $this->cleanChanges($initial, $path, true);
-        $urls = $target->getSourceUrls();
+        $urls = $this->prepareUrls($target->getSourceUrls());
 
         $exception = null;
         while ($url = array_shift($urls)) {
             try {
-                if (Filesystem::isLocalPath($url)) {
-                    $url = realpath($url);
-                }
                 $this->doUpdate($initial, $target, $path, $url);
 
                 $exception = null;
@@ -167,8 +189,6 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
             }
         }
 
-        $this->reapplyChanges($path);
-
         // print the commit logs if in verbose mode and VCS metadata is present
         // because in case of missing metadata code would trigger another exception
         if (!$exception && $this->io->isVerbose() && $this->hasMetadataRepository($path)) {
@@ -204,7 +224,6 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
     public function remove(PackageInterface $package, $path)
     {
         $this->io->writeError("  - Removing <info>" . $package->getName() . "</info> (<comment>" . $package->getPrettyVersion() . "</comment>)");
-        $this->cleanChanges($package, $path, false);
         if (!$this->filesystem->removeDirectory($path)) {
             throw new \RuntimeException('Could not completely delete '.$path.', aborting.');
         }
@@ -243,7 +262,7 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
     }
 
     /**
-     * Guarantee that no changes have been made to the local copy
+     * Reapply previously stashes changes if applicable, only called after an update (regardless if successful or not)
      *
      * @param  string            $path
      * @throws \RuntimeException in case the operation must be aborted or the patch does not apply cleanly
@@ -252,12 +271,26 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
     {
     }
 
+    /**
+     * Downloads data needed to run an install/update later
+     *
+     * @param PackageInterface      $package     package instance
+     * @param string                $path        download path
+     * @param string                $url         package url
+     * @param PackageInterface|null $prevPackage previous package (in case of an update)
+     *
+     * @return PromiseInterface|null
+     */
+    abstract protected function doDownload(PackageInterface $package, $path, $url, PackageInterface $prevPackage = null);
+
     /**
      * Downloads specific package into specific folder.
      *
      * @param PackageInterface $package package instance
      * @param string           $path    download path
      * @param string           $url     package url
+     *
+     * @return PromiseInterface|null
      */
     abstract protected function doInstall(PackageInterface $package, $path, $url);
 
@@ -268,6 +301,8 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
      * @param PackageInterface $target  updated package
      * @param string           $path    download path
      * @param string           $url     package url
+     *
+     * @return PromiseInterface|null
      */
     abstract protected function doUpdate(PackageInterface $initial, PackageInterface $target, $path, $url);
 
@@ -289,4 +324,33 @@ abstract class VcsDownloader implements DownloaderInterface, ChangeReportInterfa
      * @return bool
      */
     abstract protected function hasMetadataRepository($path);
+
+    private function prepareUrls(array $urls)
+    {
+        foreach ($urls as $index => $url) {
+            if (Filesystem::isLocalPath($url)) {
+                // realpath() below will not understand
+                // url that starts with "file://"
+                $fileProtocol = 'file://';
+                $isFileProtocol = false;
+                if (0 === strpos($url, $fileProtocol)) {
+                    $url = substr($url, strlen($fileProtocol));
+                    $isFileProtocol = true;
+                }
+
+                // realpath() below will not understand %20 spaces etc.
+                if (false !== strpos($url, '%')) {
+                    $url = rawurldecode($url);
+                }
+
+                $urls[$index] = realpath($url);
+
+                if ($isFileProtocol) {
+                    $urls[$index] = $fileProtocol . $urls[$index];
+                }
+            }
+        }
+
+        return $urls;
+    }
 }

src/Composer/Downloader/ZipDownloader.php

@@ -47,7 +47,7 @@ class ZipDownloader extends ArchiveDownloader
     /**
      * {@inheritDoc}
      */
-    public function download(PackageInterface $package, $path, $output = true)
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null, $output = true)
     {
         if (null === self::$hasSystemUnzip) {
             $finder = new ExecutableFinder;
@@ -76,7 +76,7 @@ class ZipDownloader extends ArchiveDownloader
             }
         }
 
-        return parent::download($package, $path, $output);
+        return parent::download($package, $path, $prevPackage, $output);
     }
 
     /**

src/Composer/Installer/InstallationManager.php

@@ -177,11 +177,52 @@ class InstallationManager
             $promise = $installer->download($target, $operation->getInitialPackage());
         }
 
-        if (isset($promise)) {
+        if (!empty($promise)) {
             $this->loop->wait(array($promise));
         }
 
-        $this->$method($repo, $operation);
+        $e = null;
+        try {
+            if ($method === 'install' || $method === 'uninstall') {
+                $package = $operation->getPackage();
+                $installer = $this->getInstaller($package->getType());
+                $promise = $installer->prepare($method, $package);
+            } elseif ($method === 'update') {
+                $target = $operation->getTargetPackage();
+                $targetType = $target->getType();
+                $installer = $this->getInstaller($targetType);
+                $promise = $installer->prepare('update', $target, $operation->getInitialPackage());
+            }
+
+            if (!empty($promise)) {
+                $this->loop->wait(array($promise));
+            }
+
+            $promise = $this->$method($repo, $operation);
+            if (!empty($promise)) {
+                $this->loop->wait(array($promise));
+            }
+        } catch (\Exception $e) {
+        }
+
+        if ($method === 'install' || $method === 'uninstall') {
+            $package = $operation->getPackage();
+            $installer = $this->getInstaller($package->getType());
+            $promise = $installer->cleanup($method, $package);
+        } elseif ($method === 'update') {
+            $target = $operation->getTargetPackage();
+            $targetType = $target->getType();
+            $installer = $this->getInstaller($targetType);
+            $promise = $installer->cleanup('update', $target, $operation->getInitialPackage());
+        }
+
+        if (!empty($promise)) {
+            $this->loop->wait(array($promise));
+        }
+
+        if ($e) {
+            throw $e;
+        }
     }
 
     /**
@@ -194,8 +235,10 @@ class InstallationManager
     {
         $package = $operation->getPackage();
         $installer = $this->getInstaller($package->getType());
-        $installer->install($repo, $package);
+        $promise = $installer->install($repo, $package);
         $this->markForNotification($package);
+
+        return $promise;
     }
 
     /**
@@ -214,13 +257,15 @@ class InstallationManager
 
         if ($initialType === $targetType) {
             $installer = $this->getInstaller($initialType);
-            $installer->update($repo, $initial, $target);
+            $promise = $installer->update($repo, $initial, $target);
             $this->markForNotification($target);
         } else {
             $this->getInstaller($initialType)->uninstall($repo, $initial);
             $installer = $this->getInstaller($targetType);
-            $installer->install($repo, $target);
+            $promise = $installer->install($repo, $target);
         }
+
+        return $promise;
     }
 
     /**
@@ -233,7 +278,8 @@ class InstallationManager
     {
         $package = $operation->getPackage();
         $installer = $this->getInstaller($package->getType());
-        $installer->uninstall($repo, $package);
+
+        return $installer->uninstall($repo, $package);
     }
 
     /**

src/Composer/Installer/InstallerInterface.php

@@ -46,26 +46,43 @@ interface InstallerInterface
     /**
      * Downloads the files needed to later install the given package.
      *
-     * @param  PackageInterface $package     package instance
-     * @param  PackageInterface $prevPackage previous package instance in case of an update
+     * @param  PackageInterface      $package     package instance
+     * @param  PackageInterface      $prevPackage previous package instance in case of an update
      * @return PromiseInterface|null
      */
     public function download(PackageInterface $package, PackageInterface $prevPackage = null);
 
+    /**
+     * Do anything that needs to be done between all downloads have been completed and the actual operation is executed
+     *
+     * All packages get first downloaded, then all together prepared, then all together installed/updated/uninstalled. Therefore
+     * for error recovery it is important to avoid failing during install/update/uninstall as much as possible, and risky things or
+     * user prompts should happen in the prepare step rather. In case of failure, cleanup() will be called so that changes can
+     * be undone as much as possible.
+     *
+     * @param  string                $type        one of install/update/uninstall
+     * @param  PackageInterface      $package     package instance
+     * @param  PackageInterface      $prevPackage previous package instance in case of an update
+     * @return PromiseInterface|null
+     */
+    public function prepare($type, PackageInterface $package, PackageInterface $prevPackage = null);
+
     /**
      * Installs specific package.
      *
-     * @param InstalledRepositoryInterface $repo    repository in which to check
-     * @param PackageInterface             $package package instance
+     * @param  InstalledRepositoryInterface $repo    repository in which to check
+     * @param  PackageInterface             $package package instance
+     * @return PromiseInterface|null
      */
     public function install(InstalledRepositoryInterface $repo, PackageInterface $package);
 
     /**
      * Updates specific package.
      *
-     * @param InstalledRepositoryInterface $repo    repository in which to check
-     * @param PackageInterface             $initial already installed package version
-     * @param PackageInterface             $target  updated version
+     * @param  InstalledRepositoryInterface $repo    repository in which to check
+     * @param  PackageInterface             $initial already installed package version
+     * @param  PackageInterface             $target  updated version
+     * @return PromiseInterface|null
      *
      * @throws InvalidArgumentException if $initial package is not installed
      */
@@ -74,11 +91,26 @@ interface InstallerInterface
     /**
      * Uninstalls specific package.
      *
-     * @param InstalledRepositoryInterface $repo    repository in which to check
-     * @param PackageInterface             $package package instance
+     * @param  InstalledRepositoryInterface $repo    repository in which to check
+     * @param  PackageInterface             $package package instance
+     * @return PromiseInterface|null
      */
     public function uninstall(InstalledRepositoryInterface $repo, PackageInterface $package);
 
+    /**
+     * Do anything to cleanup changes applied in the prepare or install/update/uninstall steps
+     *
+     * Note that cleanup will be called for all packages regardless if they failed an operation or not, to give
+     * all installers a change to cleanup things they did previously, so you need to keep track of changes
+     * applied in the installer/downloader themselves.
+     *
+     * @param  string                $type        one of install/update/uninstall
+     * @param  PackageInterface      $package     package instance
+     * @param  PackageInterface      $prevPackage previous package instance in case of an update
+     * @return PromiseInterface|null
+     */
+    public function cleanup($type, PackageInterface $package, PackageInterface $prevPackage = null);
+
     /**
      * Returns the installation path of a package
      *

src/Composer/Installer/LibraryInstaller.php

@@ -85,6 +85,9 @@ class LibraryInstaller implements InstallerInterface, BinaryPresenceInterface
         return (Platform::isWindows() && $this->filesystem->isJunction($installPath)) || is_link($installPath);
     }
 
+    /**
+     * {@inheritDoc}
+     */
     public function download(PackageInterface $package, PackageInterface $prevPackage = null)
     {
         $this->initializeVendorDir();
@@ -93,6 +96,28 @@ class LibraryInstaller implements InstallerInterface, BinaryPresenceInterface
         return $this->downloadManager->download($package, $downloadPath, $prevPackage);
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        $this->initializeVendorDir();
+        $downloadPath = $this->getInstallPath($package);
+
+        return $this->downloadManager->prepare($type, $package, $downloadPath, $prevPackage);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        $this->initializeVendorDir();
+        $downloadPath = $this->getInstallPath($package);
+
+        return $this->downloadManager->cleanup($type, $package, $downloadPath, $prevPackage);
+    }
+
     /**
      * {@inheritDoc}
      */

src/Composer/Installer/MetapackageInstaller.php

@@ -55,6 +55,22 @@ class MetapackageInstaller implements InstallerInterface
         // noop
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        // noop
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        // noop
+    }
+
     /**
      * {@inheritDoc}
      */

src/Composer/Installer/NoopInstaller.php

@@ -47,6 +47,20 @@ class NoopInstaller implements InstallerInterface
     {
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+    }
+
     /**
      * {@inheritDoc}
      */

src/Composer/Installer/ProjectInstaller.php

@@ -71,6 +71,22 @@ class ProjectInstaller implements InstallerInterface
         return $this->downloadManager->download($package, $installPath, $prevPackage);
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function prepare($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        $this->downloadManager->prepare($type, $package, $this->installPath, $prevPackage);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function cleanup($type, PackageInterface $package, PackageInterface $prevPackage = null)
+    {
+        $this->downloadManager->cleanup($type, $package, $this->installPath, $prevPackage);
+    }
+
     /**
      * {@inheritDoc}
      */

src/Composer/Util/Git.php

@@ -224,6 +224,10 @@ class Git
 
     public function syncMirror($url, $dir)
     {
+        if (getenv('COMPOSER_DISABLE_NETWORK')) {
+            return false;
+        }
+
         // update the repo if it is a valid git repository
         if (is_dir($dir) && 0 === $this->process->execute('git rev-parse --git-dir', $output, $dir) && trim($output) === '.') {
             try {
@@ -260,9 +264,7 @@ class Git
             }
         }
 
-        $this->syncMirror($url, $dir);
-
-        return false;
+        return $this->syncMirror($url, $dir);
     }
 
     private function isAuthenticationFailure($url, &$match)

tests/Composer/Test/Downloader/FossilDownloaderTest.php

@@ -48,7 +48,7 @@ class FossilDownloaderTest extends TestCase
     /**
      * @expectedException \InvalidArgumentException
      */
-    public function testDownloadForPackageWithoutSourceReference()
+    public function testInstallForPackageWithoutSourceReference()
     {
         $packageMock = $this->getMockBuilder('Composer\Package\PackageInterface')->getMock();
         $packageMock->expects($this->once())
@@ -59,7 +59,7 @@ class FossilDownloaderTest extends TestCase
         $downloader->install($packageMock, '/path');
     }
 
-    public function testDownload()
+    public function testInstall()
     {
         $packageMock = $this->getMockBuilder('Composer\Package\PackageInterface')->getMock();
         $packageMock->expects($this->any())
@@ -104,7 +104,9 @@ class FossilDownloaderTest extends TestCase
             ->will($this->returnValue(null));
 
         $downloader = $this->getDownloaderMock();
+        $downloader->prepare('update', $sourcePackageMock, '/path', $initialPackageMock);
         $downloader->update($initialPackageMock, $sourcePackageMock, '/path');
+        $downloader->cleanup('update', $sourcePackageMock, '/path', $initialPackageMock);
     }
 
     public function testUpdate()
@@ -140,7 +142,9 @@ class FossilDownloaderTest extends TestCase
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+        $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
         $downloader->update($packageMock, $packageMock, $this->workingDir);
+        $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
     }
 
     public function testRemove()

tests/Composer/Test/Downloader/GitDownloaderTest.php

@@ -17,6 +17,7 @@ use Composer\Config;
 use Composer\Test\TestCase;
 use Composer\Util\Filesystem;
 use Composer\Util\Platform;
+use Prophecy\Argument;
 
 class GitDownloaderTest extends TestCase
 {
@@ -79,7 +80,10 @@ class GitDownloaderTest extends TestCase
             ->will($this->returnValue(null));
 
         $downloader = $this->getDownloaderMock();
+        $downloader->download($packageMock, '/path');
+        $downloader->prepare('install', $packageMock, '/path');
         $downloader->install($packageMock, '/path');
+        $downloader->cleanup('install', $packageMock, '/path');
     }
 
     public function testDownload()
@@ -130,7 +134,10 @@ class GitDownloaderTest extends TestCase
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+        $downloader->download($packageMock, 'composerPath');
+        $downloader->prepare('install', $packageMock, 'composerPath');
         $downloader->install($packageMock, 'composerPath');
+        $downloader->cleanup('install', $packageMock, 'composerPath');
     }
 
     public function testDownloadWithCache()
@@ -195,7 +202,10 @@ class GitDownloaderTest extends TestCase
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, $config, $processExecutor);
+        $downloader->download($packageMock, 'composerPath');
+        $downloader->prepare('install', $packageMock, 'composerPath');
         $downloader->install($packageMock, 'composerPath');
+        $downloader->cleanup('install', $packageMock, 'composerPath');
         @rmdir($cachePath);
     }
 
@@ -265,7 +275,10 @@ class GitDownloaderTest extends TestCase
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
+        $downloader->download($packageMock, 'composerPath');
+        $downloader->prepare('install', $packageMock, 'composerPath');
         $downloader->install($packageMock, 'composerPath');
+        $downloader->cleanup('install', $packageMock, 'composerPath');
     }
 
     public function pushUrlProvider()
@@ -329,12 +342,12 @@ class GitDownloaderTest extends TestCase
         $config->merge(array('config' => array('github-protocols' => $protocols)));
 
         $downloader = $this->getDownloaderMock(null, $config, $processExecutor);
+        $downloader->download($packageMock, 'composerPath');
+        $downloader->prepare('install', $packageMock, 'composerPath');
         $downloader->install($packageMock, 'composerPath');
+        $downloader->cleanup('install', $packageMock, 'composerPath');
     }
 
-    /**
-     * @expectedException \RuntimeException
-     */
     public function testDownloadThrowsRuntimeExceptionIfGitCommandFails()
     {
         $expectedGitCommand = $this->winCompat("git clone --no-checkout 'https://example.com/composer/composer' 'composerPath' && cd 'composerPath' && git remote add composer 'https://example.com/composer/composer' && git fetch composer");
@@ -359,8 +372,20 @@ class GitDownloaderTest extends TestCase
             ->with($this->equalTo($expectedGitCommand))
             ->will($this->returnValue(1));
 
-        $downloader = $this->getDownloaderMock(null, null, $processExecutor);
-        $downloader->install($packageMock, 'composerPath');
+        // not using PHPUnit's expected exception because Prophecy exceptions extend from RuntimeException too so it is not safe
+        try {
+            $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+            $downloader->download($packageMock, 'composerPath');
+            $downloader->prepare('install', $packageMock, 'composerPath');
+            $downloader->install($packageMock, 'composerPath');
+            $downloader->cleanup('install', $packageMock, 'composerPath');
+            $this->fail('This test should throw');
+        } catch (\RuntimeException $e) {
+            if ('RuntimeException' !== get_class($e)) {
+                throw $e;
+            }
+            $this->assertEquals('RuntimeException', get_class($e));
+        }
     }
 
     /**
@@ -375,7 +400,10 @@ class GitDownloaderTest extends TestCase
             ->will($this->returnValue(null));
 
         $downloader = $this->getDownloaderMock();
+        $downloader->download($sourcePackageMock, '/path', $initialPackageMock);
+        $downloader->prepare('update', $sourcePackageMock, '/path', $initialPackageMock);
         $downloader->update($initialPackageMock, $sourcePackageMock, '/path');
+        $downloader->cleanup('update', $sourcePackageMock, '/path', $initialPackageMock);
     }
 
     public function testUpdate()
@@ -392,39 +420,22 @@ class GitDownloaderTest extends TestCase
         $packageMock->expects($this->any())
             ->method('getVersion')
             ->will($this->returnValue('1.0.0.0'));
-        $processExecutor = $this->getMockBuilder('Composer\Util\ProcessExecutor')->getMock();
-        $processExecutor->expects($this->at(0))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git show-ref --head -d")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(1))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git status --porcelain --untracked-files=no")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(2))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(3))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(4))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat($expectedGitUpdateCommand)), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(5))
-            ->method('execute')
-            ->with($this->equalTo('git branch -r'))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(6))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git checkout 'ref' -- && git reset --hard 'ref' --")), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
-            ->will($this->returnValue(0));
+
+        $process = $this->prophesize('Composer\Util\ProcessExecutor');
+        $process->execute($this->winCompat('git --version'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git show-ref --head -d'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git status --porcelain --untracked-files=no'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git remote -v'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git branch -r'), Argument::cetera())->willReturn(0);
+        $process->execute($expectedGitUpdateCommand, null, $this->winCompat($this->workingDir))->willReturn(0)->shouldBeCalled();
+        $process->execute($this->winCompat("git checkout 'ref' -- && git reset --hard 'ref' --"), null, $this->winCompat($this->workingDir))->willReturn(0)->shouldBeCalled();
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
-        $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
+        $downloader = $this->getDownloaderMock(null, new Config(), $process->reveal());
+        $downloader->download($packageMock, $this->workingDir, $packageMock);
+        $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
         $downloader->update($packageMock, $packageMock, $this->workingDir);
+        $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
     }
 
     public function testUpdateWithNewRepoUrl()
@@ -444,27 +455,20 @@ class GitDownloaderTest extends TestCase
         $packageMock->expects($this->any())
             ->method('getVersion')
             ->will($this->returnValue('1.0.0.0'));
+
         $processExecutor = $this->getMockBuilder('Composer\Util\ProcessExecutor')->getMock();
         $processExecutor->expects($this->at(0))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git show-ref --head -d")))
+            ->with($this->equalTo($this->winCompat("git --version")))
             ->will($this->returnValue(0));
         $processExecutor->expects($this->at(1))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git status --porcelain --untracked-files=no")))
+            ->with($this->equalTo($this->winCompat("git show-ref --head -d")))
             ->will($this->returnValue(0));
         $processExecutor->expects($this->at(2))
             ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnCallback(function ($cmd, &$output, $cwd) {
-                $output = 'origin https://github.com/old/url (fetch)
-origin https://github.com/old/url (push)
-composer https://github.com/old/url (fetch)
-composer https://github.com/old/url (push)
-';
-
-                return 0;
-            }));
+            ->with($this->equalTo($this->winCompat("git status --porcelain --untracked-files=no")))
+            ->will($this->returnValue(0));
         $processExecutor->expects($this->at(3))
             ->method('execute')
             ->with($this->equalTo($this->winCompat("git remote -v")))
@@ -482,26 +486,41 @@ composer https://github.com/old/url (push)
             ->with($this->equalTo($this->winCompat("git checkout 'ref' -- && git reset --hard 'ref' --")), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
             ->will($this->returnValue(0));
         $processExecutor->expects($this->at(7))
+            ->method('execute')
+            ->with($this->equalTo($this->winCompat("git remote -v")))
+            ->will($this->returnCallback(function ($cmd, &$output, $cwd) {
+                $output = 'origin https://github.com/old/url (fetch)
+origin https://github.com/old/url (push)
+composer https://github.com/old/url (fetch)
+composer https://github.com/old/url (push)
+';
+
+                return 0;
+            }));
+        $processExecutor->expects($this->at(8))
             ->method('execute')
             ->with($this->equalTo($this->winCompat("git remote set-url origin 'https://github.com/composer/composer'")), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
             ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(8))
+        $processExecutor->expects($this->at(9))
             ->method('execute')
             ->with($this->equalTo($this->winCompat("git remote set-url --push origin 'git@github.com:composer/composer.git'")), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
             ->will($this->returnValue(0));
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
         $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
+        $downloader->download($packageMock, $this->workingDir, $packageMock);
+        $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
         $downloader->update($packageMock, $packageMock, $this->workingDir);
+        $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
     }
 
     /**
      * @group failing
-     * @expectedException \RuntimeException
      */
     public function testUpdateThrowsRuntimeExceptionIfGitCommandFails()
     {
         $expectedGitUpdateCommand = $this->winCompat("git remote set-url composer 'https://github.com/composer/composer' && git rev-parse --quiet --verify 'ref^{commit}' || (git fetch composer && git fetch --tags composer)");
+        $expectedGitUpdateCommand2 = $this->winCompat("git remote set-url composer 'git@github.com:composer/composer' && git rev-parse --quiet --verify 'ref^{commit}' || (git fetch composer && git fetch --tags composer)");
 
         $packageMock = $this->getMockBuilder('Composer\Package\PackageInterface')->getMock();
         $packageMock->expects($this->any())
@@ -513,36 +532,38 @@ composer https://github.com/old/url (push)
         $packageMock->expects($this->any())
             ->method('getVersion')
             ->will($this->returnValue('1.0.0.0'));
-        $processExecutor = $this->getMockBuilder('Composer\Util\ProcessExecutor')->getMock();
-        $processExecutor->expects($this->at(0))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git show-ref --head -d")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(1))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git status --porcelain --untracked-files=no")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(2))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(3))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(4))
-            ->method('execute')
-            ->with($this->equalTo($expectedGitUpdateCommand))
-            ->will($this->returnValue(1));
+
+        $process = $this->prophesize('Composer\Util\ProcessExecutor');
+        $process->execute($this->winCompat('git --version'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git show-ref --head -d'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git status --porcelain --untracked-files=no'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git remote -v'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git branch -r'), Argument::cetera())->willReturn(0);
+        $process->execute($expectedGitUpdateCommand, null, $this->winCompat($this->workingDir))->willReturn(1)->shouldBeCalled();
+        $process->execute($expectedGitUpdateCommand2, null, $this->winCompat($this->workingDir))->willReturn(1)->shouldBeCalled();
+        $process->getErrorOutput()->willReturn('');
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
-        $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
-        $downloader->update($packageMock, $packageMock, $this->workingDir);
+
+        // not using PHPUnit's expected exception because Prophecy exceptions extend from RuntimeException too so it is not safe
+        try {
+            $downloader = $this->getDownloaderMock(null, new Config(), $process->reveal());
+            $downloader->download($packageMock, $this->workingDir, $packageMock);
+            $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
+            $downloader->update($packageMock, $packageMock, $this->workingDir);
+            $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
+            $this->fail('This test should throw');
+        } catch (\RuntimeException $e) {
+            if ('RuntimeException' !== get_class($e)) {
+                throw $e;
+            }
+            $this->assertEquals('RuntimeException', get_class($e));
+        }
     }
 
     public function testUpdateDoesntThrowsRuntimeExceptionIfGitCommandFailsAtFirstButIsAbleToRecover()
     {
-        $expectedFirstGitUpdateCommand = $this->winCompat("git remote set-url composer '' && git rev-parse --quiet --verify 'ref^{commit}' || (git fetch composer && git fetch --tags composer)");
+        $expectedFirstGitUpdateCommand = $this->winCompat("git remote set-url composer '".(Platform::isWindows() ? 'C:\\' : '/')."' && git rev-parse --quiet --verify 'ref^{commit}' || (git fetch composer && git fetch --tags composer)");
         $expectedSecondGitUpdateCommand = $this->winCompat("git remote set-url composer 'https://github.com/composer/composer' && git rev-parse --quiet --verify 'ref^{commit}' || (git fetch composer && git fetch --tags composer)");
 
         $packageMock = $this->getMockBuilder('Composer\Package\PackageInterface')->getMock();
@@ -554,52 +575,24 @@ composer https://github.com/old/url (push)
             ->will($this->returnValue('1.0.0.0'));
         $packageMock->expects($this->any())
             ->method('getSourceUrls')
-            ->will($this->returnValue(array('/foo/bar', 'https://github.com/composer/composer')));
-        $processExecutor = $this->getMockBuilder('Composer\Util\ProcessExecutor')->getMock();
-        $processExecutor->expects($this->at(0))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git show-ref --head -d")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(1))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git status --porcelain --untracked-files=no")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(2))
-           ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(3))
-           ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(4))
-            ->method('execute')
-            ->with($this->equalTo($expectedFirstGitUpdateCommand))
-            ->will($this->returnValue(1));
-        $processExecutor->expects($this->at(6))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git --version")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(7))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(8))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git remote -v")))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(9))
-            ->method('execute')
-            ->with($this->equalTo($expectedSecondGitUpdateCommand))
-            ->will($this->returnValue(0));
-        $processExecutor->expects($this->at(11))
-            ->method('execute')
-            ->with($this->equalTo($this->winCompat("git checkout 'ref' -- && git reset --hard 'ref' --")), $this->equalTo(null), $this->equalTo($this->winCompat($this->workingDir)))
-            ->will($this->returnValue(0));
+            ->will($this->returnValue(array(Platform::isWindows() ? 'C:\\' : '/', 'https://github.com/composer/composer')));
+
+        $process = $this->prophesize('Composer\Util\ProcessExecutor');
+        $process->execute($this->winCompat('git --version'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git show-ref --head -d'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git status --porcelain --untracked-files=no'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git remote -v'), Argument::cetera())->willReturn(0);
+        $process->execute($this->winCompat('git branch -r'), Argument::cetera())->willReturn(0);
+        $process->execute($expectedFirstGitUpdateCommand, Argument::cetera())->willReturn(1)->shouldBeCalled();
+        $process->execute($expectedSecondGitUpdateCommand, Argument::cetera())->willReturn(0)->shouldBeCalled();
+        $process->execute($this->winCompat("git checkout 'ref' -- && git reset --hard 'ref' --"), null, $this->winCompat($this->workingDir))->willReturn(0)->shouldBeCalled();
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
-        $downloader = $this->getDownloaderMock(null, new Config(), $processExecutor);
+        $downloader = $this->getDownloaderMock(null, new Config(), $process->reveal());
+        $downloader->download($packageMock, $this->workingDir, $packageMock);
+        $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
         $downloader->update($packageMock, $packageMock, $this->workingDir);
+        $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
     }
 
     public function testDowngradeShowsAppropriateMessage()
@@ -644,7 +637,10 @@ composer https://github.com/old/url (push)
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
         $downloader = $this->getDownloaderMock($ioMock, null, $processExecutor);
+        $downloader->download($newPackage, $this->workingDir, $oldPackage);
+        $downloader->prepare('update', $newPackage, $this->workingDir, $oldPackage);
         $downloader->update($oldPackage, $newPackage, $this->workingDir);
+        $downloader->cleanup('update', $newPackage, $this->workingDir, $oldPackage);
     }
 
     public function testNotUsingDowngradingWithReferences()
@@ -679,11 +675,14 @@ composer https://github.com/old/url (push)
         $ioMock = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
         $ioMock->expects($this->at(0))
             ->method('writeError')
-            ->with($this->stringContains('updating'));
+            ->with($this->stringContains('Updating'));
 
         $this->fs->ensureDirectoryExists($this->workingDir.'/.git');
         $downloader = $this->getDownloaderMock($ioMock, null, $processExecutor);
+        $downloader->download($newPackage, $this->workingDir, $oldPackage);
+        $downloader->prepare('update', $newPackage, $this->workingDir, $oldPackage);
         $downloader->update($oldPackage, $newPackage, $this->workingDir);
+        $downloader->cleanup('update', $newPackage, $this->workingDir, $oldPackage);
     }
 
     public function testRemove()
@@ -703,7 +702,9 @@ composer https://github.com/old/url (push)
             ->will($this->returnValue(true));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor, $filesystem);
+        $downloader->prepare('uninstall', $packageMock, 'composerPath');
         $downloader->remove($packageMock, 'composerPath');
+        $downloader->cleanup('uninstall', $packageMock, 'composerPath');
     }
 
     public function testGetInstallationSource()

tests/Composer/Test/Downloader/HgDownloaderTest.php

@@ -98,7 +98,9 @@ class HgDownloaderTest extends TestCase
             ->will($this->returnValue(null));
 
         $downloader = $this->getDownloaderMock();
+        $downloader->prepare('update', $sourcePackageMock, '/path', $initialPackageMock);
         $downloader->update($initialPackageMock, $sourcePackageMock, '/path');
+        $downloader->cleanup('update', $sourcePackageMock, '/path', $initialPackageMock);
     }
 
     public function testUpdate()
@@ -129,7 +131,9 @@ class HgDownloaderTest extends TestCase
             ->will($this->returnValue(0));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor);
+        $downloader->prepare('update', $packageMock, $this->workingDir, $packageMock);
         $downloader->update($packageMock, $packageMock, $this->workingDir);
+        $downloader->cleanup('update', $packageMock, $this->workingDir, $packageMock);
     }
 
     public function testRemove()
@@ -148,7 +152,9 @@ class HgDownloaderTest extends TestCase
             ->will($this->returnValue(true));
 
         $downloader = $this->getDownloaderMock(null, null, $processExecutor, $filesystem);
+        $downloader->prepare('uninstall', $packageMock, 'composerPath');
         $downloader->remove($packageMock, 'composerPath');
+        $downloader->cleanup('uninstall', $packageMock, 'composerPath');
     }
 
     public function testGetInstallationSource()

tests/Composer/Test/Downloader/ZipDownloaderTest.php

@@ -338,7 +338,7 @@ class ZipDownloaderTest extends TestCase
 
 class MockedZipDownloader extends ZipDownloader
 {
-    public function download(PackageInterface $package, $path, $output = true)
+    public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null, $output = true)
     {
         return;
     }