From 9f6f8fd12b54fbefe0c7f8b86c11fb1104293a01 Mon Sep 17 00:00:00 2001
From: Dion Hulse <dd32@git.wordpress.org>
Date: Mon, 3 May 2010 00:37:11 +0000
Subject: [PATCH] Serve a canonical redirection for ?p=, ?page_id=,
 ?attachment_id= url's for incorrect post_types (ie. ?p=<page_id> will
 redirect to that page url). Fixes #13125

git-svn-id: https://develop.svn.wordpress.org/trunk@14355 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-includes/canonical.php | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/wp-includes/canonical.php b/wp-includes/canonical.php
index 7d7da1bc82..e2551fb71e 100644
--- a/wp-includes/canonical.php
+++ b/wp-includes/canonical.php
@@ -81,7 +81,15 @@ function redirect_canonical($requested_url=null, $do_redirect=true) {
 
 	// These tests give us a WP-generated permalink
 	if ( is_404() ) {
-		$redirect_url = redirect_guess_404_permalink();
+
+		// Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
+		$id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id'));
+		if ( $id && $redirect_url = get_permalink($id) )
+			$redirect['query'] = remove_query_arg(array('p', 'page_id', 'attachment_id'), $redirect['query']);
+	
+		if ( ! $redirect_url )
+			$redirect_url = redirect_guess_404_permalink();
+
 	} elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
 		// rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
 		if ( is_attachment() && !empty($_GET['attachment_id']) && ! $redirect_url ) {