Add RootAliasPackage, fixes #1842

src/Composer/Installer.php

@@ -174,11 +174,14 @@ class Installer
             $this->downloadManager->setPreferDist(true);
         }
 
-        // create installed repo, this contains all local packages + platform packages (php & extensions)
+        // clone root package to have one in the installed repo that does not require anything
+        // we don't want it to be uninstallable, but its requirements should not conflict
+        // with the lock file for example
         $installedRootPackage = clone $this->package;
         $installedRootPackage->setRequires(array());
         $installedRootPackage->setDevRequires(array());
 
+        // create installed repo, this contains all local packages + platform packages (php & extensions)
         $localRepo = $this->repositoryManager->getLocalRepository();
         $platformRepo = new PlatformRepository();
         $repos = array(

src/Composer/Package/Loader/ArrayLoader.php

@@ -14,6 +14,8 @@ namespace Composer\Package\Loader;
 
 use Composer\Package;
 use Composer\Package\AliasPackage;
+use Composer\Package\RootAliasPackage;
+use Composer\Package\RootPackageInterface;
 use Composer\Package\Version\VersionParser;
 
 /**
@@ -184,7 +186,11 @@ class ArrayLoader implements LoaderInterface
         }
 
         if ($aliasNormalized = $this->getBranchAlias($config)) {
-            $package = new AliasPackage($package, $aliasNormalized, preg_replace('{(\.9{7})+}', '.x', $aliasNormalized));
+            if ($package instanceof RootPackageInterface) {
+                $package = new RootAliasPackage($package, $aliasNormalized, preg_replace('{(\.9{7})+}', '.x', $aliasNormalized));
+            } else {
+                $package = new AliasPackage($package, $aliasNormalized, preg_replace('{(\.9{7})+}', '.x', $aliasNormalized));
+            }
         }
 
         return $package;

src/Composer/Package/Loader/RootPackageLoader.php

@@ -65,10 +65,10 @@ class RootPackageLoader extends ArrayLoader
             $version = $config['version'];
         }
 
-        $package = parent::load($config, $class);
+        $realPackage = $package = parent::load($config, $class);
 
-        if ($package instanceof AliasPackage) {
+        if ($realPackage instanceof AliasPackage) {
-            $package = $package->getAliasOf();
+            $realPackage = $package->getAliasOf();
         }
 
         $aliases = array();
@@ -79,7 +79,7 @@ class RootPackageLoader extends ArrayLoader
                 $linkInfo = BasePackage::$supportedLinkTypes[$linkType];
                 $method = 'get'.ucfirst($linkInfo['method']);
                 $links = array();
-                foreach ($package->$method() as $link) {
+                foreach ($realPackage->$method() as $link) {
                     $links[$link->getTarget()] = $link->getConstraint()->getPrettyString();
                 }
                 $aliases = $this->extractAliases($links, $aliases);
@@ -88,23 +88,23 @@ class RootPackageLoader extends ArrayLoader
             }
         }
 
-        $package->setAliases($aliases);
+        $realPackage->setAliases($aliases);
-        $package->setStabilityFlags($stabilityFlags);
+        $realPackage->setStabilityFlags($stabilityFlags);
-        $package->setReferences($references);
+        $realPackage->setReferences($references);
 
         if (isset($config['minimum-stability'])) {
-            $package->setMinimumStability(VersionParser::normalizeStability($config['minimum-stability']));
+            $realPackage->setMinimumStability(VersionParser::normalizeStability($config['minimum-stability']));
         }
 
         if (isset($config['prefer-stable'])) {
-            $package->setPreferStable((bool) $config['prefer-stable']);
+            $realPackage->setPreferStable((bool) $config['prefer-stable']);
         }
 
         $repos = Factory::createDefaultRepositories(null, $this->config, $this->manager);
         foreach ($repos as $repo) {
             $this->manager->addRepository($repo);
         }
-        $package->setRepositories($this->config->getRepositories());
+        $realPackage->setRepositories($this->config->getRepositories());
 
         return $package;
     }

src/Composer/Package/RootAliasPackage.php

@@ -0,0 +1,89 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Package;
+
+use Composer\Package\LinkConstraint\VersionConstraint;
+use Composer\Package\Version\VersionParser;
+
+/**
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ */
+class RootAliasPackage extends AliasPackage implements RootPackageInterface
+{
+    public function __construct(RootPackageInterface $aliasOf, $version, $prettyVersion)
+    {
+        parent::__construct($aliasOf, $version, $prettyVersion);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getAliases()
+    {
+        return $this->aliasOf->getAliases();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getMinimumStability()
+    {
+        return $this->aliasOf->getMinimumStability();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getStabilityFlags()
+    {
+        return $this->aliasOf->getStabilityFlags();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getReferences()
+    {
+        return $this->aliasOf->getReferences();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getPreferStable()
+    {
+        return $this->aliasOf->getPreferStable();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function setRequires(array $require)
+    {
+        return $this->aliasOf->setRequires($require);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function setDevRequires(array $devRequire)
+    {
+        return $this->aliasOf->setDevRequires($devRequire);
+    }
+
+    public function __clone()
+    {
+        parent::__clone();
+        $this->aliasOf = clone $this->aliasOf;
+    }
+}

src/Composer/Package/RootPackageInterface.php

@@ -50,4 +50,25 @@ interface RootPackageInterface extends CompletePackageInterface
      * @return array
      */
     public function getReferences();
+
+    /**
+     * Returns true if the root package prefers picking stable packages over unstable ones
+     *
+     * @return bool
+     */
+    public function getPreferStable();
+
+    /**
+     * Set the required packages
+     *
+     * @param array $requires A set of package links
+     */
+    public function setRequires(array $requires);
+
+    /**
+     * Set the recommended packages
+     *
+     * @param array $devRequires A set of package links
+     */
+    public function setDevRequires(array $devRequires);
 }