Zend Framework

--- library/Zend/Config.php	(revision 14089)
+++ library/Zend/Config.php	(working copy)
@@ -56,6 +56,13 @@
      */
     protected $_data;
 
+    /**
+     * Flag to use when unsetting during config iteration
+     *
+     * @link http://framework.zend.com/issues/browse/ZF-5771
+     * @var boolean
+     */
+    protected $_iterationUnsetFlag;
 
     /**
      * Contains which config file sections were loaded. This is null
@@ -223,6 +230,7 @@
         if ($this->_allowModifications) {
             unset($this->_data[$name]);
             $this->_count = count($this->_data);
+            $this->_iterationUnsetFlag = true;
         } else {
             /** @see Zend_Config_Exception */
             require_once 'Zend/Config/Exception.php';
@@ -267,6 +275,10 @@
      */
     public function next()
     {
+        if ($this->_iterationUnsetFlag) {
+            $this->_iterationUnsetFlag = false;
+            return;
+        }
         next($this->_data);
         $this->_index++;
     }

unset($config->first);
foreach($config as $key=>$item) {
    echo $key . PHP_EOL;
}

Index: Config.php
===================================================================
--- Config.php	(revision 14089)
+++ Config.php	(working copy)
@@ -84,6 +84,13 @@
     protected $_loadFileErrorStr = null;

     /**
+     * Contains the index keys of the configuration data array.
+     *
+     * @var array
+     */
+    protected $_indexes = array();
+
+    /**
      * Zend_Config provides a property based interface to
      * an array. The data are read-only unless $allowModifications
      * is set to true on construction.
@@ -100,6 +107,7 @@
         $this->_allowModifications = (boolean) $allowModifications;
         $this->_loadedSection = null;
         $this->_index = 0;
+        $this->_indexes = array_keys($array);
         $this->_data = array();
         foreach ($array as $key => $value) {
             if (is_array($value)) {
@@ -155,6 +163,9 @@
             } else {
                 $this->_data[$name] = $value;
             }
+            if (!in_array($name, $this->_indexes)) {
+                $this->_indexes[] = $name;
+            }
             $this->_count = count($this->_data);
         } else {
             /** @see Zend_Config_Exception */
@@ -222,7 +233,10 @@
     {
         if ($this->_allowModifications) {
             unset($this->_data[$name]);
+            unset($this->_indexes[array_search($name, $this->_indexes)]);
+            $this->_indexes = array_values($this->_indexes);
             $this->_count = count($this->_data);
+            --$this->_index;
         } else {
             /** @see Zend_Config_Exception */
             require_once 'Zend/Config/Exception.php';
@@ -248,7 +262,10 @@
      */
     public function current()
     {
-        return current($this->_data);
+        if (!array_key_exists($key = $this->key(), $this->_data)) {
+            return false;
+        }
+        return $this->_data[$key];
     }

     /**
@@ -258,7 +275,7 @@
      */
     public function key()
     {
-        return key($this->_data);
+        return $this->_indexes[$this->_index];
     }

     /**
@@ -267,8 +284,7 @@
      */
     public function next()
     {
-        next($this->_data);
-        $this->_index++;
+        ++$this->_index;
     }

     /**
@@ -277,7 +293,6 @@
      */
     public function rewind()
     {
-        reset($this->_data);
         $this->_index = 0;
     }

foreach ($config as $key => $value)
{
    echo $key . PHP_EOL;
    if ($key == 'first') {
        unset($config->$key);
    }
}

first
second
third

unset($config->first);
foreach($config as $key=>$item) {
    echo $key . PHP_EOL;
}

second
third

[jan@jason Zend]# phpunit ConfigTest.php
PHPUnit 3.3.13 by Sebastian Bergmann.

.......................

Time: 0 seconds

OK (23 tests, 58 assertions)