From 504bc044d8e1249c8ab0c02244e57cf220af2b6a Mon Sep 17 00:00:00 2001
From: ryan <ryan@1a063a9b-81f0-0310-95a4-ce76da25c4cd>
Date: Mon, 8 Dec 2008 19:29:42 +0000
Subject: [PATCH] Check for circular post parent dependencies.  Exclude the
 current post and its children from the parent dropdown.

git-svn-id: http://svn.automattic.com/wordpress/trunk@10129 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/edit-page-form.php |  2 +-
 wp-includes/post.php        | 30 +++++++++++++++++++++++++++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/wp-admin/edit-page-form.php b/wp-admin/edit-page-form.php
index e65be6224..823305595 100644
--- a/wp-admin/edit-page-form.php
+++ b/wp-admin/edit-page-form.php
@@ -270,7 +270,7 @@ function page_attributes_meta_box($post){
 ?>
 <h5><?php _e('Parent') ?></h5>
 <label class="hidden" for="parent_id"><?php _e('Page Parent') ?></label>
-<?php wp_dropdown_pages(array('selected' => $post->post_parent, 'name' => 'parent_id', 'show_option_none' => __('Main Page (no parent)'))); ?>
+<?php wp_dropdown_pages(array('exclude_tree' => $post->ID, 'selected' => $post->post_parent, 'name' => 'parent_id', 'show_option_none' => __('Main Page (no parent)'))); ?>
 <p><?php _e('You can arrange your pages in hierarchies, for example you could have an &#8220;About&#8221; page that has &#8220;Life Story&#8221; and &#8220;My Dog&#8221; pages under it. There are no limits to how deeply nested you can make pages.'); ?></p>
 <?php
 	if ( 0 != count( get_page_templates() ) ) {
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 4df56bb46..f4c4ce11a 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -1417,6 +1417,18 @@ function wp_insert_post($postarr = array(), $wp_error = false) {
 	else
 		$post_parent = 0;
 
+	if ( !empty($post_ID) ) {
+		if ( $post_parent == $post_ID ) {
+			// Post can't be its own parent
+			$post_parent = 0;
+		} elseif ( !empty($post_parent) ) {
+			$parent_post = get_post($post_parent);
+			// Check for circular dependency
+			if ( $parent_post->post_parent == $post_ID )
+				$post_parent = 0;
+		}
+	}
+
 	if ( isset($menu_order) )
 		$menu_order = (int) $menu_order;
 	else
@@ -2059,7 +2071,7 @@ function &get_pages($args = '') {
 		'sort_column' => 'post_title', 'hierarchical' => 1,
 		'exclude' => '', 'include' => '',
 		'meta_key' => '', 'meta_value' => '',
-		'authors' => '', 'parent' => -1
+		'authors' => '', 'parent' => -1, 'exclude_tree' => ''
 	);
 
 	$r = wp_parse_args( $args, $defaults );
@@ -2170,6 +2182,22 @@ function &get_pages($args = '') {
 	if ( $child_of || $hierarchical )
 		$pages = & get_page_children($child_of, $pages);
 
+	if ( !empty($exclude_tree) ) {
+		$exclude = array();
+		
+		$exclude = (int) $exclude_tree;
+		$children = get_page_children($exclude, $pages);
+		$excludes = array();
+		foreach ( $children as $child )
+			$excludes[] = $child->ID;
+		$excludes[] = $exclude;
+		$total = count($pages);
+		for ( $i = 0; $i < $total; $i++ ) {
+			if ( in_array($pages[$i]->ID, $excludes) )
+				unset($pages[$i]);
+		}
+	}
+
 	$cache[ $key ] = $pages;
 	wp_cache_set( 'get_pages', $cache, 'posts' );