Merge branch 'hotfix/4450' into develop

Forward port #4450

library/Zend/Db/ResultSet/AbstractResultSet.php

@@ -18,7 +18,6 @@
 
 abstract class AbstractResultSet implements Iterator, ResultSetInterface
 {
-
     /**
      * if -1, datasource is already buffered
      * if -2, implicitly disabling buffering in ResultSet
@@ -58,13 +57,21 @@ abstract class AbstractResultSet implements Iterator, ResultSetInterface
      */
     public function initialize($dataSource)
     {
+        // reset buffering
+        if (is_array($this->buffer)) {
+            $this->buffer = array();
+        }
+
         if ($dataSource instanceof ResultInterface) {
             $this->count = $dataSource->count();
             $this->fieldCount = $dataSource->getFieldCount();
             $this->dataSource = $dataSource;
             if ($dataSource->isBuffered()) {
                 $this->buffer = -1;
             }
+            if (is_array($this->buffer)) {
+                $this->dataSource->rewind();
+            }
             return $this;
         }
 
@@ -97,6 +104,9 @@ public function buffer()
             throw new Exception\RuntimeException('Buffering must be enabled before iteration is started');
         } elseif ($this->buffer === null) {
             $this->buffer = array();
+            if ($this->dataSource instanceof ResultInterface) {
+                $this->dataSource->rewind();
+            }
         }
         return $this;
     }
@@ -211,7 +221,6 @@ public function valid()
             $key = key($this->dataSource);
             return ($key !== null);
         }
-
     }
 
     /**