From e7fc2383df8922eef9edd7406370e57bc0808a8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Hojtsy?= <gabor@hojtsy.hu>
Date: Tue, 18 Dec 2007 16:24:01 +0000
Subject: #192767 by fago, Eaton, chx: taking form_state per reference in form
 constructor function. Will be replaced with a nicer PHP 5 solution in Drupal
 7.

---
 includes/common.inc | 17 +++++++++++++++++
 includes/form.inc   | 22 +++++++++++++++++-----
 2 files changed, 34 insertions(+), 5 deletions(-)

(limited to 'includes')

diff --git a/includes/common.inc b/includes/common.inc
index 8c47f0036..353010634 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -2832,8 +2832,25 @@ function drupal_system_listing($mask, $directory, $key = 'name', $min_depth = 1)
  *   hook_$type_alter functions.
  */
 function drupal_alter($type, &$data) {
+  // PHP's func_get_args() always returns copies of params, not references, so
+  // drupal_alter() can only manipulate data that comes in via the required first
+  // param. For the edge case functions that must pass in an arbitrary number of
+  // alterable parameters (hook_form_alter() being the best example), an array of
+  // those params can be placed in the __drupal_alter_by_ref key of the $data
+  // array. This is somewhat ugly, but is an unavoidable consequence of a flexible
+  // drupal_alter() function, and the limitations of func_get_args().
+  // @todo: Remove this in Drupal 7.
+  if (isset($data['__drupal_alter_by_ref'])) {
+    $by_ref_parameters = $data['__drupal_alter_by_ref'];
+    unset($data['__drupal_alter_by_ref']);
+  }
+
   // Hang onto a reference to the data array so that it isn't blown away later.
+  // Also, merge in any parameters that need to be passed by reference.
   $args = array(&$data);
+  if (isset($by_ref_parameters)) {
+    $args = array_merge($args, $by_ref_parameters);
+  }
 
   // Now, use func_get_args() to pull in any additional parameters passed into
   // the drupal_alter() call.
diff --git a/includes/form.inc b/includes/form.inc
index 088893b74..6155a3584 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -78,7 +78,7 @@ function drupal_get_form($form_id) {
       // Use a copy of the function's arguments for manipulation
       $args_temp = $args;
       array_shift($args_temp);
-      array_unshift($args_temp, $form_state);
+      array_unshift($args_temp, &$form_state);
       array_unshift($args_temp, $form_id);
 
       $form = call_user_func_array('drupal_retrieve_form', $args_temp);
@@ -173,7 +173,7 @@ function drupal_rebuild_form($form_id, &$form_state, $args, $form_build_id = NUL
   // callback. Neither is needed.
   array_shift($args);
   // Put in the current state.
-  array_unshift($args, $form_state);
+  array_unshift($args, &$form_state);
   // And the form_id.
   array_unshift($args, $form_id);
   $form = call_user_func_array('drupal_retrieve_form', $args);
@@ -333,7 +333,7 @@ function drupal_retrieve_form($form_id, &$form_state) {
     }
   }
 
-  array_unshift($args, $form_state);
+  array_unshift($args, &$form_state);
 
   // If $callback was returned by a hook_forms() implementation, call it.
   // Otherwise, call the function named after the form id.
@@ -497,8 +497,20 @@ function drupal_prepare_form($form_id, &$form, &$form_state) {
     }
   }
 
-  drupal_alter('form_'. $form_id, $form, $form_state);
-  drupal_alter('form', $form, $form_state, $form_id);
+  // Normally, we would call drupal_alter($form_id, $form, $form_state).
+  // However, drupal_alter() normally supports just one byref parameter. Using
+  // the __drupal_alter_by_ref key, we can store any additional parameters
+  // that need to be altered, and they'll be split out into additional params
+  // for the hook_form_alter() implementations.
+  // @todo: Remove this in Drupal 7.
+  $data = &$form;
+  $data['__drupal_alter_by_ref'] = array(&$form_state);
+  drupal_alter('form_'. $form_id, $data);
+
+  // __drupal_alter_by_ref is unset in the drupal_alter() function, we need
+  // to repopulate it to ensure both calls get the data.
+  $data['__drupal_alter_by_ref'] = array(&$form_state);
+  drupal_alter('form', $data, $form_id);
 }
 
 
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