Fix root aliasing with new providers repo format

src/Composer/DependencyResolver/Pool.php

@@ -83,6 +83,7 @@ class Pool
 
             if ($repo instanceof ComposerRepository && $repo->hasProviders()) {
                 $this->composerRepos[] = $repo;
+                $repo->setRootAliases($rootAliases);
                 $repo->resetPackageIds();
             } elseif ($repo instanceof StreamableRepositoryInterface) {
                 foreach ($repo->getMinimalPackages() as $package) {

src/Composer/Repository/ComposerRepository.php

@@ -40,6 +40,7 @@ class ComposerRepository extends ArrayRepository implements NotifiableRepository
     protected $providers = array();
     protected $providersByUid = array();
     protected $loader;
+    protected $rootAliases;
     private $rawData;
     private $minimalPackages;
     private $degradedMode = false;
@@ -103,6 +104,11 @@ class ComposerRepository extends ArrayRepository implements NotifiableRepository
         @file_get_contents($url, false, $context);
     }
 
+    public function setRootAliases(array $rootAliases)
+    {
+        $this->rootAliases = $rootAliases;
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -250,6 +256,10 @@ class ComposerRepository extends ArrayRepository implements NotifiableRepository
                         } else {
                             $this->providers[$name][$version['uid']] = $this->providersByUid[$version['uid']];
                         }
+                        // check for root aliases
+                        if (isset($this->providersByUid[$version['uid'].'-root'])) {
+                            $this->providers[$name][$version['uid'].'-root'] = $this->providersByUid[$version['uid'].'-root'];
+                        }
                     }
                 } else {
                     if (!$pool->isPackageAcceptable($version['name'], VersionParser::parseStability($version['version']))) {
@@ -271,6 +281,23 @@ class ComposerRepository extends ArrayRepository implements NotifiableRepository
                         // override provider with its alias so it can be expanded in the if block above
                         $this->providersByUid[$version['uid']] = $alias;
                     }
+
+                    // handle root package aliases
+                    unset($rootAliasData);
+
+                    if (isset($this->rootAliases[$name][$package->getVersion()])) {
+                        $rootAliasData = $this->rootAliases[$name][$package->getVersion()];
+                    } elseif (($aliasNormalized = $package->getAlias()) && isset($this->rootAliases[$name][$aliasNormalized])) {
+                        $rootAliasData = $this->rootAliases[$name][$aliasNormalized];
+                    }
+
+                    if (isset($rootAliasData)) {
+                        $alias = $this->createAliasPackage($package, $rootAliasData['alias_normalized'], $rootAliasData['alias']);
+                        $alias->setRepository($this);
+
+                        $this->providers[$name][$version['uid'].'-root'] = $alias;
+                        $this->providersByUid[$version['uid'].'-root'] = $alias;
+                    }
                 }
             }
         }