Add --strict-psr flag to dump-autoload to fail the process if psr violations were detected

doc/03-cli.md

@@ -921,6 +921,8 @@ performance.
 * **--ignore-platform-req:** ignore a specific platform requirement (`php`, `hhvm`,
   `lib-*` and `ext-*`) and skip the [platform check](07-runtime.md#platform-check) for it.
   Multiple requirements can be ignored via wildcard.
+* **--strict-psr:** Return a failed status code (1) if PSR-4 or PSR-0 mapping errors
+  are present. Requires --optimize to work.
 
 ## clear-cache / clearcache / cc
 

src/Composer/Autoload/AutoloadGenerator.php

@@ -12,6 +12,7 @@
 
 namespace Composer\Autoload;
 
+use Composer\ClassMapGenerator\ClassMap;
 use Composer\ClassMapGenerator\ClassMapGenerator;
 use Composer\Config;
 use Composer\EventDispatcher\EventDispatcher;
@@ -161,7 +162,7 @@ public function setPlatformRequirementFilter(PlatformRequirementFilterInterface
     /**
      * @param string $targetDir
      * @param bool $scanPsrPackages
-     * @return int
+     * @return ClassMap
      * @throws \Seld\JsonLint\ParsingException
      * @throws \RuntimeException
      */
@@ -445,7 +446,7 @@ public static function autoload(\$class)
             ));
         }
 
-        return \count($classMap);
+        return $classMap;
     }
 
     /**

src/Composer/Command/DumpAutoloadCommand.php

@@ -41,6 +41,7 @@ protected function configure()
                 new InputOption('no-dev', null, InputOption::VALUE_NONE, 'Disables autoload-dev rules. Composer will by default infer this automatically according to the last install or update --no-dev state.'),
                 new InputOption('ignore-platform-req', null, InputOption::VALUE_REQUIRED | InputOption::VALUE_IS_ARRAY, 'Ignore a specific platform requirement (php & ext- packages).'),
                 new InputOption('ignore-platform-reqs', null, InputOption::VALUE_NONE, 'Ignore all platform requirements (php & ext- packages).'),
+                new InputOption('strict-psr', null, InputOption::VALUE_NONE, 'Return a failed status code (1) if PSR-4 or PSR-0 mapping errors are present. Requires --optimize to work.'),
             ))
             ->setHelp(
                 <<<EOT
@@ -69,6 +70,10 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $apcuPrefix = $input->getOption('apcu-prefix');
         $apcu = $apcuPrefix !== null || $input->getOption('apcu') || $config->get('apcu-autoloader');
 
+        if ($input->getOption('strict-psr') && !$optimize) {
+            throw new \InvalidArgumentException('--strict-psr mode only works with optimized autoloader, use --optimize if you want a strict return value.');
+        }
+
         if ($authoritative) {
             $this->getIO()->write('<info>Generating optimized autoload files (authoritative)</info>');
         } elseif ($optimize) {
@@ -91,7 +96,8 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $generator->setRunScripts(true);
         $generator->setApcu($apcu, $apcuPrefix);
         $generator->setPlatformRequirementFilter($this->getPlatformRequirementFilter($input));
-        $numberOfClasses = $generator->dump($config, $localRepo, $package, $installationManager, 'composer', $optimize);
+        $classMap = $generator->dump($config, $localRepo, $package, $installationManager, 'composer', $optimize);
+        $numberOfClasses = count($classMap);
 
         if ($authoritative) {
             $this->getIO()->write('<info>Generated optimized autoload files (authoritative) containing '. $numberOfClasses .' classes</info>');
@@ -101,6 +107,10 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $this->getIO()->write('<info>Generated autoload files</info>');
         }
 
+        if ($input->getOption('strict-psr') && count($classMap->getPsrViolations()) > 0) {
+            return 1;
+        }
+
         return 0;
     }
 }