diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index a91c398f4a..66e256f840 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -3785,8 +3785,12 @@ function _drupal_shutdown_function() {
   chdir(DRUPAL_ROOT);
 
   try {
-    while (list($key, $callback) = each($callbacks)) {
+    // Manually iterate over the array instead of using a foreach loop.
+    // A foreach operates on a copy of the array, so any shutdown functions that
+    // were added from other shutdown functions would never be called.
+    while ($callback = current($callbacks)) {
       call_user_func_array($callback['callback'], $callback['arguments']);
+      next($callbacks);
     }
   }
   catch (Exception $exception) {
diff --git a/includes/form.inc b/includes/form.inc
index e749239ef9..54e77ab8d5 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -1438,10 +1438,11 @@ function _form_validate(&$elements, &$form_state, $form_id = NULL) {
       // length if it's a string, and the item count if it's an array.
       // An unchecked checkbox has a #value of integer 0, different than string
       // '0', which could be a valid value.
-      $is_empty_multiple = (!count($elements['#value']));
+      $is_empty_multiple = (is_array($elements['#value']) || $elements['#value'] instanceof Countable) && count($elements['#value']) === 0;
+      $is_empty_null = $elements['#value'] === NULL;
       $is_empty_string = (is_string($elements['#value']) && drupal_strlen(trim($elements['#value'])) == 0);
       $is_empty_value = ($elements['#value'] === 0);
-      if ($is_empty_multiple || $is_empty_string || $is_empty_value) {
+      if ($is_empty_multiple || $is_empty_string || $is_empty_value || $is_empty_null) {
         // Although discouraged, a #title is not mandatory for form elements. In
         // case there is no #title, we cannot set a form error message.
         // Instead of setting no #title, form constructors are encouraged to set
diff --git a/includes/install.inc b/includes/install.inc
index 5e1d3c6326..b7db783586 100644
--- a/includes/install.inc
+++ b/includes/install.inc
@@ -779,7 +779,7 @@ function drupal_uninstall_modules($module_list = array(), $uninstall_dependents
     $module_list = array_flip(array_values($module_list));
 
     $profile = drupal_get_profile();
-    while (list($module) = each($module_list)) {
+    foreach (array_keys($module_list) as $module) {
       if (!isset($module_data[$module]) || drupal_get_installed_schema_version($module) == SCHEMA_UNINSTALLED) {
         // This module doesn't exist or is already uninstalled. Skip it.
         unset($module_list[$module]);
diff --git a/includes/menu.inc b/includes/menu.inc
index 4664d27e89..ca37ba509d 100644
--- a/includes/menu.inc
+++ b/includes/menu.inc
@@ -576,7 +576,8 @@ function _menu_load_objects(&$item, &$map) {
           // 'load arguments' in the hook_menu() entry, but they need
           // some processing. In this case the $function is the key to the
           // load_function array, and the value is the list of arguments.
-          list($function, $args) = each($function);
+          $args = current($function);
+          $function = key($function);
           $load_functions[$index] = $function;
 
           // Some arguments are placeholders for dynamic items to process.
@@ -2402,7 +2403,8 @@ function menu_set_active_trail($new_trail = NULL) {
       // a stripped down menu tree containing the active trail only, in case
       // the given menu has not been built in this request yet.
       $tree = menu_tree_page_data($preferred_link['menu_name'], NULL, TRUE);
-      list($key, $curr) = each($tree);
+      $curr = current($tree);
+      next($tree);
     }
     // There is no link for the current path.
     else {
@@ -2432,7 +2434,8 @@ function menu_set_active_trail($new_trail = NULL) {
         }
         $tree = $curr['below'] ? $curr['below'] : array();
       }
-      list($key, $curr) = each($tree);
+      $curr = current($tree);
+      next($tree);
     }
     // Make sure the current page is in the trail to build the page title, by
     // appending either the preferred link or the menu router item for the
diff --git a/includes/module.inc b/includes/module.inc
index 2e251080b7..4c2b3fbeeb 100644
--- a/includes/module.inc
+++ b/includes/module.inc
@@ -404,7 +404,11 @@ function module_enable($module_list, $enable_dependencies = TRUE) {
     // Create an associative array with weights as values.
     $module_list = array_flip(array_values($module_list));
 
-    while (list($module) = each($module_list)) {
+    // The array is iterated over manually (instead of using a foreach) because
+    // modules may be added to the list within the loop and we need to process
+    // them.
+    while ($module = key($module_list)) {
+      next($module_list);
       if (!isset($module_data[$module])) {
         // This module is not found in the filesystem, abort.
         return FALSE;
@@ -540,7 +544,11 @@ function module_disable($module_list, $disable_dependents = TRUE) {
     $module_list = array_flip(array_values($module_list));
 
     $profile = drupal_get_profile();
-    while (list($module) = each($module_list)) {
+    // The array is iterated over manually (instead of using a foreach) because
+    // modules may be added to the list within the loop and we need to process
+    // them.
+    while ($module = key($module_list)) {
+      next($module_list);
       if (!isset($module_data[$module]) || !$module_data[$module]->status) {
         // This module doesn't exist or is already disabled, skip it.
         unset($module_list[$module]);
diff --git a/includes/theme.inc b/includes/theme.inc
index 9b606e9fb1..b574fd7473 100644
--- a/includes/theme.inc
+++ b/includes/theme.inc
@@ -1986,11 +1986,11 @@ function theme_breadcrumb($variables) {
  *     rows.
  */
 function theme_table($variables) {
-  $header = $variables['header'];
-  $rows = $variables['rows'];
+  $header = (array) $variables['header'];
+  $rows = (array) $variables['rows'];
   $attributes = $variables['attributes'];
   $caption = $variables['caption'];
-  $colgroups = $variables['colgroups'];
+  $colgroups = (array) $variables['colgroups'];
   $sticky = $variables['sticky'];
   $empty = $variables['empty'];
 
diff --git a/modules/book/book.module b/modules/book/book.module
index 7afed9ae42..32047f93f5 100644
--- a/modules/book/book.module
+++ b/modules/book/book.module
@@ -768,11 +768,13 @@ function book_prev($book_link) {
     return NULL;
   }
   $flat = book_get_flat_menu($book_link);
-  // Assigning the array to $flat resets the array pointer for use with each().
+  reset($flat);
   $curr = NULL;
   do {
     $prev = $curr;
-    list($key, $curr) = each($flat);
+    $curr = current($flat);
+    $key = key($flat);
+    next($flat);
   } while ($key && $key != $book_link['mlid']);
 
   if ($key == $book_link['mlid']) {
@@ -806,9 +808,10 @@ function book_prev($book_link) {
  */
 function book_next($book_link) {
   $flat = book_get_flat_menu($book_link);
-  // Assigning the array to $flat resets the array pointer for use with each().
+  reset($flat);
   do {
-    list($key, $curr) = each($flat);
+    $key = key($flat);
+    next($flat);
   }
   while ($key && $key != $book_link['mlid']);
 
diff --git a/modules/locale/locale.test b/modules/locale/locale.test
index db87e05548..b890b06147 100644
--- a/modules/locale/locale.test
+++ b/modules/locale/locale.test
@@ -3188,11 +3188,7 @@ class LocaleLanguageNegotiationInfoFunctionalTest extends DrupalWebTestCase {
     foreach (language_types_info() as $type => $info) {
       if (isset($info['fixed'])) {
         $negotiation = variable_get("language_negotiation_$type", array());
-        $equal = count($info['fixed']) == count($negotiation);
-        while ($equal && list($id) = each($negotiation)) {
-          list(, $info_id) = each($info['fixed']);
-          $equal = $info_id == $id;
-        }
+        $equal = array_keys($negotiation) === array_values($info['fixed']);
         $this->assertTrue($equal, format_string('language negotiation for %type is properly set up', array('%type' => $type)));
       }
     }
diff --git a/modules/system/system.tar.inc b/modules/system/system.tar.inc
index 86e4e3de4a..fbf285c006 100644
--- a/modules/system/system.tar.inc
+++ b/modules/system/system.tar.inc
@@ -41,8 +41,8 @@
 
  /**
  * Note on Drupal 8 porting.
- * This file origin is Tar.php, release 1.4.0 (stable) with some code
- * from PEAR.php, release 1.9.5 (stable) both at http://pear.php.net.
+ * This file origin is Tar.php, release 1.4.3 (stable) with some code
+ * from PEAR.php, release 1.10.5 (stable) both at http://pear.php.net.
  * To simplify future porting from pear of this file, you should not
  * do cosmetic or other non significant changes to this file.
  * The following changes have been done:
@@ -259,6 +259,17 @@ class Archive_Tar
                 return false;
             }
         }
+
+        if (version_compare(PHP_VERSION, "5.5.0-dev") < 0) {
+            $this->_fmt = "a100filename/a8mode/a8uid/a8gid/a12size/a12mtime/" .
+                   "a8checksum/a1typeflag/a100link/a6magic/a2version/" .
+                   "a32uname/a32gname/a8devmajor/a8devminor/a131prefix";
+        } else {
+            $this->_fmt = "Z100filename/Z8mode/Z8uid/Z8gid/Z12size/Z12mtime/" .
+                   "Z8checksum/Z1typeflag/Z100link/Z6magic/Z2version/" .
+                   "Z32uname/Z32gname/Z8devmajor/Z8devminor/Z131prefix";
+        }
+
     }
 
     public function __destruct()
@@ -278,7 +289,7 @@ class Archive_Tar
     * @param string $ext The extension name
     * @return bool Success or not on the dl() call
     */
-    function loadExtension($ext)
+    public static function loadExtension($ext)
     {
         if (extension_loaded($ext)) {
             return true;
@@ -287,8 +298,7 @@ class Archive_Tar
         // if either returns true dl() will produce a FATAL error, stop that
         if (
             function_exists('dl') === false ||
-            ini_get('enable_dl') != 1 ||
-            ini_get('safe_mode') == 1
+            ini_get('enable_dl') != 1
         ) {
             return false;
         }
@@ -714,7 +724,7 @@ class Archive_Tar
         }
 
         // ----- Get the arguments
-        $v_att_list = & func_get_args();
+        $v_att_list = func_get_args();
 
         // ----- Read the attributes
         $i = 0;
@@ -1720,28 +1730,13 @@ class Archive_Tar
         // ----- Calculate the checksum
         $v_checksum = 0;
         // ..... First part of the header
-        for ($i = 0; $i < 148; $i++) {
-            $v_checksum += ord(substr($v_binary_data, $i, 1));
-        }
-        // ..... Ignore the checksum value and replace it by ' ' (space)
-        for ($i = 148; $i < 156; $i++) {
-            $v_checksum += ord(' ');
-        }
-        // ..... Last part of the header
-        for ($i = 156; $i < 512; $i++) {
-            $v_checksum += ord(substr($v_binary_data, $i, 1));
-        }
+        $v_binary_split = str_split($v_binary_data);
+        $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 0, 148)));
+        $v_checksum += array_sum(array_map('ord', array(' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',)));
+        $v_checksum += array_sum(array_map('ord', array_slice($v_binary_split, 156, 512)));
 
-        if (version_compare(PHP_VERSION, "5.5.0-dev") < 0) {
-            $fmt = "a100filename/a8mode/a8uid/a8gid/a12size/a12mtime/" .
-                "a8checksum/a1typeflag/a100link/a6magic/a2version/" .
-                "a32uname/a32gname/a8devmajor/a8devminor/a131prefix";
-        } else {
-            $fmt = "Z100filename/Z8mode/Z8uid/Z8gid/Z12size/Z12mtime/" .
-                "Z8checksum/Z1typeflag/Z100link/Z6magic/Z2version/" .
-                "Z32uname/Z32gname/Z8devmajor/Z8devminor/Z131prefix";
-        }
-        $v_data = unpack($fmt, $v_binary_data);
+
+        $v_data = unpack($this->_fmt, $v_binary_data);
 
         if (strlen($v_data["prefix"]) > 0) {
             $v_data["filename"] = "$v_data[prefix]/$v_data[filename]";
@@ -1777,7 +1772,7 @@ class Archive_Tar
         $v_header['mode'] = OctDec(trim($v_data['mode']));
         $v_header['uid'] = OctDec(trim($v_data['uid']));
         $v_header['gid'] = OctDec(trim($v_data['gid']));
-        $v_header['size'] = OctDec(trim($v_data['size']));
+        $v_header['size'] = $this->_tarRecToSize($v_data['size']);
         $v_header['mtime'] = OctDec(trim($v_data['mtime']));
         if (($v_header['typeflag'] = $v_data['typeflag']) == "5") {
             $v_header['size'] = 0;
@@ -1796,6 +1791,40 @@ class Archive_Tar
         return true;
     }
 
+    /**
+     * Convert Tar record size to actual size
+     *
+     * @param string $tar_size
+     * @return size of tar record in bytes
+     */
+    private function _tarRecToSize($tar_size)
+    {
+        /*
+         * First byte of size has a special meaning if bit 7 is set.
+         *
+         * Bit 7 indicates base-256 encoding if set.
+         * Bit 6 is the sign bit.
+         * Bits 5:0 are most significant value bits.
+         */
+        $ch = ord($tar_size[0]);
+        if ($ch & 0x80) {
+            // Full 12-bytes record is required.
+            $rec_str = $tar_size . "\x00";
+
+            $size = ($ch & 0x40) ? -1 : 0;
+            $size = ($size << 6) | ($ch & 0x3f);
+
+            for ($num_ch = 1; $num_ch < 12; ++$num_ch) {
+                $size = ($size * 256) + ord($rec_str[$num_ch]);
+            }
+
+            return $size;
+
+        } else {
+            return OctDec(trim($tar_size));
+        }
+    }
+
     /**
      * Detect and report a malicious file name
      *