From 2934a0aad3e495d01219ea9153c494a9ebdbf7e2 Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Wed, 13 Apr 2022 12:37:09 +0200
Subject: [PATCH] Clarify that autoloader-suffix should be a non-empty-string,
 fixes #10720

---
 doc/06-config.md                            |  4 ++--
 src/Composer/Autoload/AutoloadGenerator.php | 12 ++++++------
 src/Composer/Config.php                     |  7 +++++++
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/doc/06-config.md b/doc/06-config.md
index 636cf955508c..270f1bebddca 100644
--- a/doc/06-config.md
+++ b/doc/06-config.md
@@ -315,8 +315,8 @@ with other autoloaders.
 
 ## autoloader-suffix
 
-Defaults to `null`. String to be used as a suffix for the generated Composer
-autoloader. When null a random one will be generated.
+Defaults to `null`. Non-empty string to be used as a suffix for the generated
+Composer autoloader. When null a random one will be generated.
 
 ## optimize-autoloader
 
diff --git a/src/Composer/Autoload/AutoloadGenerator.php b/src/Composer/Autoload/AutoloadGenerator.php
index 265b890d6ba4..db6a7f7637ee 100644
--- a/src/Composer/Autoload/AutoloadGenerator.php
+++ b/src/Composer/Autoload/AutoloadGenerator.php
@@ -159,12 +159,12 @@ public function setPlatformRequirementFilter(PlatformRequirementFilterInterface
     /**
      * @param string $targetDir
      * @param bool $scanPsrPackages
-     * @param string $suffix
+     * @param non-empty-string|null $suffix
      * @return int
      * @throws \Seld\JsonLint\ParsingException
      * @throws \RuntimeException
      */
-    public function dump(Config $config, InstalledRepositoryInterface $localRepo, RootPackageInterface $rootPackage, InstallationManager $installationManager, $targetDir, $scanPsrPackages = false, $suffix = '')
+    public function dump(Config $config, InstalledRepositoryInterface $localRepo, RootPackageInterface $rootPackage, InstallationManager $installationManager, $targetDir, $scanPsrPackages = false, $suffix = null)
     {
         if ($this->classMapAuthoritative) {
             // Force scanPsrPackages when classmap is authoritative
@@ -374,16 +374,16 @@ public static function autoload(\$class)
         }
         $classmapFile .= ");\n";
 
-        if (!$suffix) {
-            if (!$config->get('autoloader-suffix') && Filesystem::isReadable($vendorPath.'/autoload.php')) {
+        if (null === $suffix || '' === $suffix) {
+            if (null === $config->get('autoloader-suffix') && Filesystem::isReadable($vendorPath.'/autoload.php')) {
                 $content = file_get_contents($vendorPath.'/autoload.php');
                 if (Preg::isMatch('{ComposerAutoloaderInit([^:\s]+)::}', $content, $match)) {
                     $suffix = $match[1];
                 }
             }
 
-            if (!$suffix) {
-                $suffix = $config->get('autoloader-suffix') ?: md5(uniqid('', true));
+            if (null === $suffix) {
+                $suffix = $config->get('autoloader-suffix') ?? md5(uniqid('', true));
             }
         }
 
diff --git a/src/Composer/Config.php b/src/Composer/Config.php
index 0d927f1903d7..e81c11738572 100644
--- a/src/Composer/Config.php
+++ b/src/Composer/Config.php
@@ -427,6 +427,13 @@ public function get($key, $flags = 0)
 
                 return $protos;
 
+            case 'autoloader-suffix':
+                if ($this->config[$key] === '') { // we need to guarantee null or non-empty-string
+                    return null;
+                }
+
+                return $this->process($this->config[$key], $flags);
+
             default:
                 if (!isset($this->config[$key])) {
                     return null;