fixed bug in Cache, made Array.php compliant to its/the interfaces...

fixed bug in Cache, made Array.php compliant to its/the interfaces documentation (returning false instead of null when nothing found) and changed if statement in Hydrate to react on false, not on null too

lib/Doctrine/Cache/Array.php

@@ -52,7 +52,7 @@ class Doctrine_Cache_Array implements Countable, Doctrine_Cache_Interface
         if (isset($this->data[$id])) {
             return $this->data[$id];
         }
-        return null;
+        return false;
     }
     /**
      * Test if a cache is available or not (for the given id)

lib/Doctrine/Hydrate.php

@@ -786,10 +786,10 @@ class Doctrine_Hydrate extends Doctrine_Object implements Serializable
             // calculate hash for dql query
             $hash = md5($dql . var_export($params, true));
 
-            $cached = ($this->_expireCache) ? null : $cacheDriver->fetch($hash);
+            $cached = ($this->_expireCache) ? false : $cacheDriver->fetch($hash);
 
 
-            if ($cached === null) {
+            if ($cached === false) {
                 // cache miss
                 $stmt = $this->_execute($params);
                 $array = $this->parseData2($stmt, Doctrine::HYDRATE_ARRAY);