diff --git a/src/Composer/Cache.php b/src/Composer/Cache.php
index b6fcf17e7..b1baef8ea 100644
--- a/src/Composer/Cache.php
+++ b/src/Composer/Cache.php
@@ -61,6 +61,8 @@ class Cache
 
     /**
      * @param bool $readOnly
+     *
+     * @return void
      */
     public function setReadOnly($readOnly)
     {
@@ -76,6 +78,8 @@ class Cache
     }
 
     /**
+     * @param string $path
+     *
      * @return bool
      */
     public static function isUsable($path)
@@ -112,6 +116,8 @@ class Cache
     }
 
     /**
+     * @param string $file
+     *
      * @return string|false
      */
     public function read($file)
@@ -129,6 +135,9 @@ class Cache
     }
 
     /**
+     * @param string $file
+     * @param string $contents
+     *
      * @return bool
      */
     public function write($file, $contents)
@@ -169,6 +178,10 @@ class Cache
 
     /**
      * Copy a file into the cache
+     *
+     * @param string $file
+     * @param string $source
+     *
      * @return bool
      */
     public function copyFrom($file, $source)
@@ -191,6 +204,10 @@ class Cache
 
     /**
      * Copy a file out of the cache
+     *
+     * @param string $file
+     * @param string $target
+     *
      * @return bool
      */
     public function copyTo($file, $target)
@@ -237,6 +254,8 @@ class Cache
     }
 
     /**
+     * @param string $file
+     *
      * @return bool
      */
     public function remove($file)
@@ -266,6 +285,9 @@ class Cache
     }
 
     /**
+     * @param int $ttl
+     * @param int $maxSize
+     *
      * @return bool
      */
     public function gc($ttl, $maxSize)
@@ -299,6 +321,8 @@ class Cache
     }
 
     /**
+     * @param string $file
+     *
      * @return string|false
      */
     public function sha1($file)
@@ -314,6 +338,8 @@ class Cache
     }
 
     /**
+     * @param string $file
+     *
      * @return string|false
      */
     public function sha256($file)
diff --git a/src/Composer/Compiler.php b/src/Composer/Compiler.php
index fc34ba3f6..cd27a5f72 100644
--- a/src/Composer/Compiler.php
+++ b/src/Composer/Compiler.php
@@ -37,7 +37,10 @@ class Compiler
     /**
      * Compiles composer into a single phar file
      *
-     * @param  string            $pharFile The full path to the file to create
+     * @param string $pharFile The full path to the file to create
+     *
+     * @return void
+     *
      * @throws \RuntimeException
      */
     public function compile($pharFile = 'composer.phar')
@@ -214,7 +217,12 @@ class Compiler
         return strtr($relativePath, '\\', '/');
     }
 
-    private function addFile($phar, $file, $strip = true)
+    /**
+     * @param bool $strip
+     *
+     * @return void
+     */
+    private function addFile(\Phar $phar, \SplFileInfo $file, $strip = true)
     {
         $path = $this->getRelativeFilePath($file);
         $content = file_get_contents($file);
@@ -239,7 +247,10 @@ class Compiler
         $phar->addFromString($path, $content);
     }
 
-    private function addComposerBin($phar)
+    /**
+     * @return void
+     */
+    private function addComposerBin(\Phar $phar)
     {
         $content = file_get_contents(__DIR__.'/../../bin/composer');
         $content = preg_replace('{^#!/usr/bin/env php\s*}', '', $content);
diff --git a/src/Composer/Composer.php b/src/Composer/Composer.php
index 6c54c7884..f22a15a45 100644
--- a/src/Composer/Composer.php
+++ b/src/Composer/Composer.php
@@ -141,7 +141,6 @@ class Composer
     private $archiveManager;
 
     /**
-     * @param  RootPackageInterface $package
      * @return void
      */
     public function setPackage(RootPackageInterface $package)
@@ -158,7 +157,7 @@ class Composer
     }
 
     /**
-     * @param Config $config
+     * @return void
      */
     public function setConfig(Config $config)
     {
@@ -174,7 +173,7 @@ class Composer
     }
 
     /**
-     * @param Locker $locker
+     * @return void
      */
     public function setLocker(Locker $locker)
     {
@@ -190,7 +189,7 @@ class Composer
     }
 
     /**
-     * @param Loop $loop
+     * @return void
      */
     public function setLoop(Loop $loop)
     {
@@ -206,7 +205,7 @@ class Composer
     }
 
     /**
-     * @param RepositoryManager $manager
+     * @return void
      */
     public function setRepositoryManager(RepositoryManager $manager)
     {
@@ -222,7 +221,7 @@ class Composer
     }
 
     /**
-     * @param DownloadManager $manager
+     * @return void
      */
     public function setDownloadManager(DownloadManager $manager)
     {
@@ -238,7 +237,7 @@ class Composer
     }
 
     /**
-     * @param ArchiveManager $manager
+     * @return void
      */
     public function setArchiveManager(ArchiveManager $manager)
     {
@@ -254,7 +253,7 @@ class Composer
     }
 
     /**
-     * @param InstallationManager $manager
+     * @return void
      */
     public function setInstallationManager(InstallationManager $manager)
     {
@@ -270,7 +269,7 @@ class Composer
     }
 
     /**
-     * @param PluginManager $manager
+     * @return void
      */
     public function setPluginManager(PluginManager $manager)
     {
@@ -286,7 +285,7 @@ class Composer
     }
 
     /**
-     * @param EventDispatcher $eventDispatcher
+     * @return void
      */
     public function setEventDispatcher(EventDispatcher $eventDispatcher)
     {
@@ -302,7 +301,7 @@ class Composer
     }
 
     /**
-     * @param AutoloadGenerator $autoloadGenerator
+     * @return void
      */
     public function setAutoloadGenerator(AutoloadGenerator $autoloadGenerator)
     {
diff --git a/src/Composer/Config.php b/src/Composer/Config.php
index 175f03d35..5e0ab4bc0 100644
--- a/src/Composer/Config.php
+++ b/src/Composer/Config.php
@@ -114,6 +114,9 @@ class Config
         $this->baseDir = $baseDir;
     }
 
+    /**
+     * @return void
+     */
     public function setConfigSource(ConfigSourceInterface $source)
     {
         $this->configSource = $source;
@@ -127,6 +130,9 @@ class Config
         return $this->configSource;
     }
 
+    /**
+     * @return void
+     */
     public function setAuthConfigSource(ConfigSourceInterface $source)
     {
         $this->authConfigSource = $source;
@@ -143,7 +149,9 @@ class Config
     /**
      * Merges new config values with the existing ones (overriding)
      *
-     * @param array $config
+     * @param array<string, mixed> $config
+     *
+     * @return void
      */
     public function merge($config)
     {
@@ -184,13 +192,13 @@ class Config
             foreach ($newRepos as $name => $repository) {
                 // disable a repository by name
                 if (false === $repository) {
-                    $this->disableRepoByName($name);
+                    $this->disableRepoByName((string) $name);
                     continue;
                 }
 
                 // disable a repository with an anonymous {"name": false} repo
                 if (is_array($repository) && 1 === count($repository) && false === current($repository)) {
-                    $this->disableRepoByName(key($repository));
+                    $this->disableRepoByName((string) key($repository));
                     continue;
                 }
 
@@ -215,7 +223,7 @@ class Config
     }
 
     /**
-     * @return array
+     * @return array<int|string, mixed>
      */
     public function getRepositories()
     {
@@ -228,6 +236,7 @@ class Config
      * @param  string            $key
      * @param  int               $flags Options (see class constants)
      * @throws \RuntimeException
+     *
      * @return mixed
      */
     public function get($key, $flags = 0)
@@ -380,6 +389,8 @@ class Config
     }
 
     /**
+     * @param int $flags
+     *
      * @return array<string, mixed[]>
      */
     public function all($flags = 0)
@@ -421,6 +432,7 @@ class Config
      *
      * @param  string|int|null $value a config string that can contain {$refs-to-other-config}
      * @param  int             $flags Options (see class constants)
+     *
      * @return string|int|null
      */
     private function process($value, $flags)
@@ -471,6 +483,11 @@ class Config
         return false;
     }
 
+    /**
+     * @param string $name
+     *
+     * @return void
+     */
     private function disableRepoByName($name)
     {
         if (isset($this->repositories[$name])) {
@@ -485,6 +502,8 @@ class Config
      *
      * @param string      $url
      * @param IOInterface $io
+     *
+     * @return void
      */
     public function prohibitUrlByConfig($url, IOInterface $io = null)
     {
@@ -527,6 +546,8 @@ class Config
      *     "vendor/bin/long-running-script --watch"
      *   ]
      * }
+     *
+     * @return void
      */
     public static function disableProcessTimeout()
     {
diff --git a/src/Composer/Downloader/FileDownloader.php b/src/Composer/Downloader/FileDownloader.php
index d55c992ca..6acc697e3 100644
--- a/src/Composer/Downloader/FileDownloader.php
+++ b/src/Composer/Downloader/FileDownloader.php
@@ -88,7 +88,7 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
 
         if ($this->cache && $this->cache->gcIsNecessary()) {
             $this->io->writeError('Running cache garbage collection', true, IOInterface::VERY_VERBOSE);
-            $this->cache->gc($config->get('cache-files-ttl'), $config->get('cache-files-maxsize'));
+            $this->cache->gc((int) $config->get('cache-files-ttl'), (int) $config->get('cache-files-maxsize'));
         }
     }
 
diff --git a/src/Composer/Factory.php b/src/Composer/Factory.php
index 6d870f6b9..2cbf6e3f0 100644
--- a/src/Composer/Factory.php
+++ b/src/Composer/Factory.php
@@ -171,12 +171,13 @@ class Factory
     }
 
     /**
-     * @param  IOInterface|null $io
+     * @param string|null $cwd
+     *
      * @return Config
      */
     public static function createConfig(IOInterface $io = null, $cwd = null)
     {
-        $cwd = $cwd ?: getcwd();
+        $cwd = $cwd ?: (string) getcwd();
 
         $config = new Config(true, $cwd);
 
@@ -250,6 +251,8 @@ class Factory
     }
 
     /**
+     * @param string $composerFile
+     *
      * @return string
      */
     public static function getLockFile($composerFile)
@@ -286,18 +289,19 @@ class Factory
     /**
      * Creates a Composer instance
      *
-     * @param  IOInterface               $io             IO instance
-     * @param  array|string|null         $localConfig    either a configuration array or a filename to read from, if null it will
-     *                                                   read from the default filename
-     * @param  bool                      $disablePlugins Whether plugins should not be loaded
-     * @param  bool                      $fullLoad       Whether to initialize everything or only main project stuff (used when loading the global composer)
+     * @param  IOInterface                       $io             IO instance
+     * @param  array<string, mixed>|string|null  $localConfig    either a configuration array or a filename to read from, if null it will
+     *                                                           read from the default filename
+     * @param  bool                              $disablePlugins Whether plugins should not be loaded
+     * @param  string|null                       $cwd
+     * @param  bool                              $fullLoad       Whether to initialize everything or only main project stuff (used when loading the global composer)
      * @throws \InvalidArgumentException
      * @throws \UnexpectedValueException
      * @return Composer
      */
     public function createComposer(IOInterface $io, $localConfig = null, $disablePlugins = false, $cwd = null, $fullLoad = true)
     {
-        $cwd = $cwd ?: getcwd();
+        $cwd = $cwd ?: (string) getcwd();
 
         // load Composer configuration
         if (null === $localConfig) {
@@ -465,6 +469,8 @@ class Factory
     /**
      * @param Repository\RepositoryManager $rm
      * @param string                       $vendorDir
+     *
+     * @return void
      */
     protected function addLocalRepository(IOInterface $io, RepositoryManager $rm, $vendorDir, RootPackageInterface $rootPackage, ProcessExecutor $process = null)
     {
@@ -477,7 +483,9 @@ class Factory
     }
 
     /**
-     * @param  Config        $config
+     * @param bool $disablePlugins
+     * @param bool $fullLoad
+     *
      * @return Composer|null
      */
     protected function createGlobalComposer(IOInterface $io, Config $config, $disablePlugins, $fullLoad = false)
@@ -578,9 +586,7 @@ class Factory
     }
 
     /**
-     * @param Installer\InstallationManager $im
-     * @param Composer                      $composer
-     * @param IO\IOInterface                $io
+     * @return void
      */
     protected function createDefaultInstallers(Installer\InstallationManager $im, Composer $composer, IOInterface $io, ProcessExecutor $process = null)
     {
@@ -594,7 +600,9 @@ class Factory
 
     /**
      * @param InstalledRepositoryInterface   $repo repository to purge packages from
-     * @param Installer\InstallationManager $im   manager to check whether packages are still installed
+     * @param Installer\InstallationManager  $im   manager to check whether packages are still installed
+     *
+     * @return void
      */
     protected function purgePackages(InstalledRepositoryInterface $repo, Installer\InstallationManager $im)
     {
@@ -632,7 +640,7 @@ class Factory
      *
      * @param  IOInterface    $io      IO instance
      * @param  Config         $config  Config instance
-     * @param  array          $options Array of options passed directly to HttpDownloader constructor
+     * @param  mixed[]        $options Array of options passed directly to HttpDownloader constructor
      * @return HttpDownloader
      */
     public static function createHttpDownloader(IOInterface $io, Config $config, $options = array())
diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index e9d06e746..411c1d6e0 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -372,6 +372,11 @@ class Installer
         return 0;
     }
 
+    /**
+     * @param bool $doInstall
+     *
+     * @return int
+     */
     protected function doUpdate(InstalledRepositoryInterface $localRepo, $doInstall)
     {
         $platformRepo = $this->createPlatformRepo(true);
@@ -573,6 +578,13 @@ class Installer
     /**
      * Run the solver a second time on top of the existing update result with only the current result set in the pool
      * and see what packages would get removed if we only had the non-dev packages in the solver request
+     *
+     * @param array<int, array<string, string>> $aliases
+     *
+     * @return int
+     *
+     * @phpstan-param list<array{package: string, version: string, alias: string, alias_normalized: string}> $aliases
+     * @phpstan-return self::ERROR_*
      */
     protected function extractDevPackages(LockTransaction $lockTransaction, PlatformRepository $platformRepo, array $aliases, PolicyInterface $policy, LockArrayRepository $lockedRepository = null)
     {
@@ -740,6 +752,11 @@ class Installer
         return 0;
     }
 
+    /**
+     * @param bool $forUpdate
+     *
+     * @return PlatformRepository
+     */
     protected function createPlatformRepo($forUpdate)
     {
         if ($forUpdate) {
@@ -752,11 +769,13 @@ class Installer
     }
 
     /**
-     * @param  bool                     $forUpdate
-     * @param  PlatformRepository       $platformRepo
-     * @param  array                    $rootAliases
-     * @param  RepositoryInterface|null $lockedRepository
+     * @param  bool                              $forUpdate
+     * @param  array<int, array<string, string>> $rootAliases
+     * @param  RepositoryInterface|null          $lockedRepository
+     *
      * @return RepositorySet
+     *
+     * @phpstan-param list<array{package: string, version: string, alias: string, alias_normalized: string}> $rootAliases
      */
     private function createRepositorySet($forUpdate, PlatformRepository $platformRepo, array $rootAliases = array(), $lockedRepository = null)
     {
@@ -822,6 +841,8 @@ class Installer
     }
 
     /**
+     * @param bool $forUpdate
+     *
      * @return DefaultPolicy
      */
     private function createPolicy($forUpdate)
@@ -879,6 +900,12 @@ class Installer
         return $request;
     }
 
+    /**
+     * @param LockArrayRepository|null $lockedRepository
+     * @param bool                     $includeDevRequires
+     *
+     * @return void
+     */
     private function requirePackagesForUpdate(Request $request, LockArrayRepository $lockedRepository = null, $includeDevRequires = true)
     {
         // if we're updating mirrors we want to keep exactly the same versions installed which are in the lock file, but we want current remote metadata
@@ -907,8 +934,11 @@ class Installer
     }
 
     /**
-     * @param  bool  $forUpdate
-     * @return array
+     * @param bool $forUpdate
+     *
+     * @return array<int, array<string, string>>
+     *
+     * @phpstan-return list<array{package: string, version: string, alias: string, alias_normalized: string}>
      */
     private function getRootAliases($forUpdate)
     {
@@ -922,8 +952,9 @@ class Installer
     }
 
     /**
-     * @param  array $links
-     * @return array
+     * @param Link[] $links
+     *
+     * @return array<string, string>
      */
     private function extractPlatformRequirements(array $links)
     {
@@ -942,7 +973,7 @@ class Installer
      *
      * This is to prevent any accidental modification of the existing repos on disk
      *
-     * @param RepositoryManager $rm
+     * @return void
      */
     private function mockLocalRepositories(RepositoryManager $rm)
     {
@@ -1208,7 +1239,8 @@ class Installer
      * If this is set to false, no platform requirements are ignored
      * If this is set to string[], those packages will be ignored
      *
-     * @param  bool|array $ignorePlatformReqs
+     * @param  bool|string[] $ignorePlatformReqs
+     *
      * @return Installer
      */
     public function setIgnorePlatformRequirements($ignorePlatformReqs)
@@ -1241,7 +1273,8 @@ class Installer
      * restrict the update operation to a few packages, all other packages
      * that are already installed will be kept at their current version
      *
-     * @param  array     $packages
+     * @param string[] $packages
+     *
      * @return Installer
      */
     public function setUpdateAllowList(array $packages)
diff --git a/src/Composer/Package/Locker.php b/src/Composer/Package/Locker.php
index 924bd50c1..e96152338 100644
--- a/src/Composer/Package/Locker.php
+++ b/src/Composer/Package/Locker.php
@@ -308,7 +308,7 @@ class Locker
     /**
      * @return string[][]
      *
-     * @phpstan-return list<array<string, string>>
+     * @phpstan-return list<array{package: string, version: string, alias: string, alias_normalized: string}>
      */
     public function getAliases()
     {
@@ -350,7 +350,7 @@ class Locker
      *
      * @return bool
      *
-     * @phpstan-param list<array<string, string>> $aliases
+     * @phpstan-param list<array{package: string, version: string, alias: string, alias_normalized: string}> $aliases
      */
     public function setLockData(array $packages, $devPackages, array $platformReqs, $platformDevReqs, array $aliases, $minimumStability, array $stabilityFlags, $preferStable, $preferLowest, array $platformOverrides, $write = true)
     {
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index 8d76e7e39..3fdab432b 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -1132,8 +1132,8 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
 
         if (isset($data['includes'])) {
             foreach ($data['includes'] as $include => $metadata) {
-                if (isset($metadata['sha1']) && $this->cache->sha1($include) === $metadata['sha1']) {
-                    $includedData = json_decode($this->cache->read($include), true);
+                if (isset($metadata['sha1']) && $this->cache->sha1((string) $include) === $metadata['sha1']) {
+                    $includedData = json_decode($this->cache->read((string) $include), true);
                 } else {
                     $includedData = $this->fetchFile($include);
                 }
@@ -1215,7 +1215,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
                 }
 
                 $response = $this->httpDownloader->get($filename, $options);
-                $json = $response->getBody();
+                $json = (string) $response->getBody();
                 if ($sha256 && $sha256 !== hash('sha256', $json)) {
                     // undo downgrade before trying again if http seems to be hijacked or modifying content somehow
                     if ($this->allowSslDowngrade) {
@@ -1247,7 +1247,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
                         $lastModifiedDate = $response->getHeader('last-modified');
                         if ($lastModifiedDate) {
                             $data['last-modified'] = $lastModifiedDate;
-                            $json = json_encode($data);
+                            $json = JsonFile::encode($data, 0);
                         }
                     }
                     $this->cache->write($cacheKey, $json);
@@ -1329,7 +1329,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
                 }
                 $options['http']['header'][] = 'If-Modified-Since: '.$lastModifiedTime;
                 $response = $this->httpDownloader->get($filename, $options);
-                $json = $response->getBody();
+                $json = (string) $response->getBody();
                 if ($json === '' && $response->getStatusCode() === 304) {
                     return true;
                 }
@@ -1346,7 +1346,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
                 $response->collect();
                 if ($lastModifiedDate) {
                     $data['last-modified'] = $lastModifiedDate;
-                    $json = json_encode($data);
+                    $json = JsonFile::encode($data, 0);
                 }
                 if (!$this->cache->isReadOnly()) {
                     $this->cache->write($cacheKey, $json);
@@ -1431,7 +1431,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
                 return array('packages' => array());
             }
 
-            $json = $response->getBody();
+            $json = (string) $response->getBody();
             if ($json === '' && $response->getStatusCode() === 304) {
                 $repo->freshMetadataUrls[$filename] = true;
 
diff --git a/src/Composer/Repository/Vcs/FossilDriver.php b/src/Composer/Repository/Vcs/FossilDriver.php
index 0556f79c6..eca405ac8 100644
--- a/src/Composer/Repository/Vcs/FossilDriver.php
+++ b/src/Composer/Repository/Vcs/FossilDriver.php
@@ -50,7 +50,7 @@ class FossilDriver extends VcsDriver
         if (Filesystem::isLocalPath($this->url) && is_dir($this->url)) {
             $this->checkoutDir = $this->url;
         } else {
-            if (!Cache::isUsable($this->config->get('cache-repo-dir')) || !Cache::isUsable($this->config->get('cache-vcs-dir'))) {
+            if (!Cache::isUsable((string) $this->config->get('cache-repo-dir')) || !Cache::isUsable((string) $this->config->get('cache-vcs-dir'))) {
                 throw new \RuntimeException('FossilDriver requires a usable cache directory, and it looks like you set it to be disabled');
             }
 
diff --git a/src/Composer/Repository/Vcs/GitDriver.php b/src/Composer/Repository/Vcs/GitDriver.php
index 4fef3f702..735db2d70 100644
--- a/src/Composer/Repository/Vcs/GitDriver.php
+++ b/src/Composer/Repository/Vcs/GitDriver.php
@@ -47,7 +47,7 @@ class GitDriver extends VcsDriver
             $this->repoDir = $this->url;
             $cacheUrl = realpath($this->url);
         } else {
-            if (!Cache::isUsable($this->config->get('cache-vcs-dir'))) {
+            if (!Cache::isUsable((string) $this->config->get('cache-vcs-dir'))) {
                 throw new \RuntimeException('GitDriver requires a usable cache directory, and it looks like you set it to be disabled');
             }
 
diff --git a/src/Composer/Repository/Vcs/HgDriver.php b/src/Composer/Repository/Vcs/HgDriver.php
index 56e35ea30..560ecc972 100644
--- a/src/Composer/Repository/Vcs/HgDriver.php
+++ b/src/Composer/Repository/Vcs/HgDriver.php
@@ -41,7 +41,7 @@ class HgDriver extends VcsDriver
         if (Filesystem::isLocalPath($this->url)) {
             $this->repoDir = $this->url;
         } else {
-            if (!Cache::isUsable($this->config->get('cache-vcs-dir'))) {
+            if (!Cache::isUsable((string) $this->config->get('cache-vcs-dir'))) {
                 throw new \RuntimeException('HgDriver requires a usable cache directory, and it looks like you set it to be disabled');
             }
 
diff --git a/src/Composer/Repository/Vcs/PerforceDriver.php b/src/Composer/Repository/Vcs/PerforceDriver.php
index 602cf4dd9..1f437dbe3 100644
--- a/src/Composer/Repository/Vcs/PerforceDriver.php
+++ b/src/Composer/Repository/Vcs/PerforceDriver.php
@@ -60,7 +60,7 @@ class PerforceDriver extends VcsDriver
             return;
         }
 
-        if (!Cache::isUsable($this->config->get('cache-vcs-dir'))) {
+        if (!Cache::isUsable((string) $this->config->get('cache-vcs-dir'))) {
             throw new \RuntimeException('PerforceDriver requires a usable cache directory, and it looks like you set it to be disabled');
         }
 
diff --git a/src/Composer/Repository/Vcs/VcsDriver.php b/src/Composer/Repository/Vcs/VcsDriver.php
index 22c70211f..a9d025e05 100644
--- a/src/Composer/Repository/Vcs/VcsDriver.php
+++ b/src/Composer/Repository/Vcs/VcsDriver.php
@@ -96,7 +96,7 @@ abstract class VcsDriver implements VcsDriverInterface
             $composer = $this->getBaseComposerInformation($identifier);
 
             if ($this->shouldCache($identifier)) {
-                $this->cache->write($identifier, json_encode($composer));
+                $this->cache->write($identifier, JsonFile::encode($composer, 0));
             }
 
             $this->infoCache[$identifier] = $composer;