Undefined or default return points fixed.

src/Composer/Command/ExecCommand.php

@@ -69,7 +69,7 @@ EOT
                 );
             }
 
-            return;
+            return 0;
         }
 
         $binary = $input->getArgument('binary');

src/Composer/Command/RunScriptCommand.php

@@ -70,7 +70,7 @@ EOT
         if ($input->getOption('list')) {
             return $this->listScripts();
         } elseif (!$input->getArgument('script')) {
-            throw new \RunTimeException('Missing required argument "script"');
+            throw new \RuntimeException('Missing required argument "script"');
         }
 
         $script = $input->getArgument('script');

src/Composer/Command/ShowCommand.php

@@ -89,7 +89,7 @@ EOT
         if ($input->getOption('tree') && ($input->getOption('all') || $input->getOption('available'))) {
             $io->writeError('The --tree (-t) option is not usable in combination with --all or --available (-a)');
 
-            return;
+            return 0;
         }
 
         // init repos

src/Composer/Downloader/HgDownloader.php

@@ -69,7 +69,7 @@ class HgDownloader extends VcsDownloader
     public function getLocalChanges(PackageInterface $package, $path)
     {
         if (!is_dir($path.'/.hg')) {
-            return;
+            return null;
         }
 
         $this->process->execute('hg st', $output, realpath($path));

src/Composer/Downloader/SvnDownloader.php

@@ -73,7 +73,7 @@ class SvnDownloader extends VcsDownloader
     public function getLocalChanges(PackageInterface $package, $path)
     {
         if (!$this->hasMetadataRepository($path)) {
-            return;
+            return null;
         }
 
         $this->process->execute('svn status --ignore-externals', $output, $path);

src/Composer/Factory.php

@@ -25,6 +25,7 @@ use Composer\Util\Platform;
 use Composer\Util\ProcessExecutor;
 use Composer\Util\RemoteFilesystem;
 use Composer\Util\Silencer;
+use Seld\JsonLint\DuplicateKeyException;
 use Symfony\Component\Console\Formatter\OutputFormatterStyle;
 use Composer\EventDispatcher\EventDispatcher;
 use Composer\Autoload\AutoloadGenerator;
@@ -270,7 +271,7 @@ class Factory
             $jsonParser = new JsonParser;
             try {
                 $jsonParser->parse(file_get_contents($localConfig), JsonParser::DETECT_KEY_CONFLICTS);
-            } catch (\Seld\JsonLint\DuplicateKeyException $e) {
+            } catch (DuplicateKeyException $e) {
                 $details = $e->getDetails();
                 $io->writeError('<warning>Key '.$details['key'].' is a duplicate in '.$localConfig.' at line '.$details['line'].'</warning>');
             }

src/Composer/Package/Archiver/BaseExcludeFilter.php

@@ -83,7 +83,7 @@ abstract class BaseExcludeFilter
                     $line = trim($line);
 
                     if (!$line || 0 === strpos($line, '#')) {
-                        return;
+                        return null;
                     }
 
                     return call_user_func($lineParser, $line);

src/Composer/Package/Archiver/GitExcludeFilter.php

@@ -69,12 +69,9 @@ class GitExcludeFilter extends BaseExcludeFilter
     {
         $parts = preg_split('#\s+#', $line);
 
-        if (count($parts) != 2) {
-            return null;
-        }
-
-        if ($parts[1] === 'export-ignore') {
+        if (count($parts) == 2 && $parts[1] === 'export-ignore') {
             return $this->generatePattern($parts[0]);
         }
+        return null;
     }
 }

src/Composer/Repository/ArrayRepository.php

@@ -56,6 +56,7 @@ class ArrayRepository extends BaseRepository
                 }
             }
         }
+        return null;
     }
 
     /**

src/Composer/Repository/RepositoryManager.php

@@ -58,6 +58,7 @@ class RepositoryManager
                 return $package;
             }
         }
+        return null;
     }
 
     /**

src/Composer/Util/TlsHelper.php

@@ -70,7 +70,7 @@ final class TlsHelper
         }
 
         if (!isset($info['subject']['commonName'])) {
-            return;
+            return null;
         }
 
         $commonName = strtolower($info['subject']['commonName']);
@@ -82,6 +82,7 @@ final class TlsHelper
                 if (0 === strpos($name, 'DNS:')) {
                     return strtolower(ltrim(substr($name, 4)));
                 }
+                return null;
             }, $subjectAltNames));
             $subjectAltNames = array_values($subjectAltNames);
         }