Only show override description if there is one, refs #7011

src/Composer/DependencyResolver/Problem.php

@@ -91,15 +91,18 @@ class Problem
 
                 // handle php/hhvm
                 if ($job['packageName'] === 'php' || $job['packageName'] === 'php-64bit' || $job['packageName'] === 'hhvm') {
+                    $version = phpversion();
                     $available = $this->pool->whatProvides($job['packageName']);
-                    $firstAvailable = reset($available);
 
-                    $version = count($available) ? $firstAvailable->getPrettyVersion() : phpversion();
-                    if (count($available) && $firstAvailable instanceof CompletePackageInterface) {
-                        $version .= '; ' . $firstAvailable->getDescription();
+                    if (count($available)) {
+                        $firstAvailable = reset($available);
+                        $version = $firstAvailable->getPrettyVersion();
+                        $extra = $firstAvailable->getExtra();
+                        if ($firstAvailable instanceof CompletePackageInterface && isset($extra['config.platform']) && $extra['config.platform'] === true) {
+                            $version .= '; ' . $firstAvailable->getDescription();
+                        }
                     }
 
-
                     $msg = "\n    - This package requires ".$job['packageName'].$this->constraintToText($job['constraint']).' but ';
 
                     if (defined('HHVM_VERSION')) {