Performance: Move existing path filter until after we know it's a valid

...prefix. This caused severe performance issues in long running processes.

Author: dantleech

lib/Adapter/Composer/ComposerClassToFile.php

@@ -98,6 +98,19 @@ private function getFileCandidates(ClassName $className, array $prefixes)
         $candidates = [];
 
         foreach ($prefixes as $prefix => $paths) {
+
+            if (is_int($prefix)) {
+                $prefix = '';
+            }
+
+            if ($prefix && false === $className->beginsWith($prefix)) {
+                continue;
+            }
+
+            if (!isset($candidates[$prefix])) {
+                $candidates[$prefix] = [];
+            }
+
             $paths = (array) $paths;
             $paths = array_map(function ($path) {
                 if (!file_exists($path)) {
@@ -112,18 +125,6 @@ private function getFileCandidates(ClassName $className, array $prefixes)
                 return realpath($path);
             }, $paths);
 
-            if (is_int($prefix)) {
-                $prefix = '';
-            }
-
-            if ($prefix && false === $className->beginsWith($prefix)) {
-                continue;
-            }
-
-            if (!isset($candidates[$prefix])) {
-                $candidates[$prefix] = [];
-            }
-
             $candidates[$prefix] = array_merge($candidates[$prefix], $paths);
         }