Fix support for uppercase package names in why/why-not commands, fixes #7198

src/Composer/Command/BaseDependencyCommand.php

@@ -89,7 +89,7 @@ class BaseDependencyCommand extends BaseCommand
         );
 
         // Find packages that are or provide the requested package first
-        $packages = $pool->whatProvides($needle);
+        $packages = $pool->whatProvides(strtolower($needle));
         if (empty($packages)) {
             throw new \InvalidArgumentException(sprintf('Could not find package "%s" in your project', $needle));
         }

src/Composer/Repository/BaseRepository.php

@@ -39,7 +39,7 @@ abstract class BaseRepository implements RepositoryInterface
      */
     public function getDependents($needle, $constraint = null, $invert = false, $recurse = true, $packagesFound = null)
     {
-        $needles = (array) $needle;
+        $needles = array_map('strtolower', (array) $needle);
         $results = array();
 
         // initialize the array with the needles before any recursion occurs