From cc126b8efad9007afa6f3fe24c6c7439026c4cc4 Mon Sep 17 00:00:00 2001
From: daniel <daniel.kinzler@wikimedia.de>
Date: Fri, 5 Oct 2012 16:08:07 +0200
Subject: [PATCH] Prevent page moved to different content model.

Pages should never be moved in a way that would change their content model.
Without this explicite check, that might happen when $wgContentHandlerUseDB
is disabled.

Change-Id: Id1a101f56bee6f13a7259d34019c587e75a4c182
---
 includes/Title.php                 | 11 ++++++++++-
 languages/messages/MessagesEn.php  |  1 +
 languages/messages/MessagesQqq.php |  4 ++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/includes/Title.php b/includes/Title.php
index affffc3c68..f2531a2a1d 100644
--- a/includes/Title.php
+++ b/includes/Title.php
@@ -3375,7 +3375,7 @@ class Title {
 	 * @return Mixed True on success, getUserPermissionsErrors()-like array on failure
 	 */
 	public function isValidMoveOperation( &$nt, $auth = true, $reason = '' ) {
-		global $wgUser;
+		global $wgUser, $wgContentHandlerUseDB;
 
 		$errors = array();
 		if ( !$nt ) {
@@ -3408,6 +3408,15 @@ class Title {
 			$errors[] = array( 'badarticleerror' );
 		}
 
+		// Content model checks
+		if ( !$wgContentHandlerUseDB &&
+				$this->getContentModel() !== $nt->getContentModel() ) {
+			// can't move a page if that would change the page's content model
+			$errors[] = array( 'bad-target-model',
+							ContentHandler::getLocalizedName( $this->getContentModel() ),
+							ContentHandler::getLocalizedName( $nt->getContentModel() ) );
+		}
+
 		// Image-specific checks
 		if ( $this->getNamespace() == NS_FILE ) {
 			$errors = array_merge( $errors, $this->validateFileMoveOperation( $nt ) );
diff --git a/languages/messages/MessagesEn.php b/languages/messages/MessagesEn.php
index e96418dc0c..b25d0a5ade 100644
--- a/languages/messages/MessagesEn.php
+++ b/languages/messages/MessagesEn.php
@@ -3396,6 +3396,7 @@ cannot move a page over itself.',
 'immobile-target-namespace-iw' => 'Interwiki link is not a valid target for page move.',
 'immobile-source-page'         => 'This page is not movable.',
 'immobile-target-page'         => 'Cannot move to that destination title.',
+'bad-target-model'             => 'The desired destination uses a different content model. Can not convert from $1 to $2.',
 'imagenocrossnamespace'        => 'Cannot move file to non-file namespace',
 'nonfile-cannot-move-to-file'  => 'Cannot move non-file to file namespace',
 'imagetypemismatch'            => 'The new file extension does not match its type',
diff --git a/languages/messages/MessagesQqq.php b/languages/messages/MessagesQqq.php
index a1e4a73ad7..643f6f9b83 100644
--- a/languages/messages/MessagesQqq.php
+++ b/languages/messages/MessagesQqq.php
@@ -3191,6 +3191,10 @@ Parameters:
 'immobile-target-namespace-iw' => "This message appears when attempting to move a page, if a person has typed an interwiki link as a namespace prefix in the input box labelled 'To new title'.  The special page 'Movepage' cannot be used to move a page to another wiki.
 
 'Destination' can be used instead of 'target' in this message.",
+'bad-target-model'             => "This message is shown when attempting to move a page, but the move would change the page's content model.
+This may be the case when \$wgContentHandlerUseDB is set to false, because then a page's content model is derived from the page's title.
+* $1: The localized name of the original page's content model.
+* $2: The localized name of the content model used by the destination title.",
 'fix-double-redirects' => 'This is a checkbox in [[Special:MovePage]] which allows to move all redirects from the old title to the new title.',
 'protectedpagemovewarning' => 'Related message: [[MediaWiki:protectedpagewarning/{{#titleparts:{{PAGENAME}}|1|2}}]]
 {{Related|Semiprotectedpagewarning}}',
-- 
2.20.1