From 5dd2927e94885ccfb5873e73d4f57ab5af416e19 Mon Sep 17 00:00:00 2001
From: Rob Church <robchurch@users.mediawiki.org>
Date: Sat, 4 Aug 2007 19:15:18 +0000
Subject: [PATCH] * (bug 10805) Fix "undo" link when viewing the diff of the
 most recent change to a page using "diff=0" *
 DifferenceEngine::loadRevisionData() wasn't updating $mNewid when loading the
 newer revision, which doesn't make too much sense if it ends up left as 0
 (which is impossible)

---
 RELEASE-NOTES                 |  2 ++
 includes/DifferenceEngine.php | 20 ++++++++++----------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 3132897757..b491594b08 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -352,6 +352,8 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
 * Fixed regression in blocking of username '0'
 * (bug 9437) Don't overwrite edit form submission handler when setting up
   edit box scroll position preserve/restore behaviour
+* (bug 10805) Fix "undo" link when viewing the diff of the most recent
+  change to a page using "diff=0"
 
 == API changes since 1.10 ==
 
diff --git a/includes/DifferenceEngine.php b/includes/DifferenceEngine.php
index fbfab343fc..1deabe8810 100644
--- a/includes/DifferenceEngine.php
+++ b/includes/DifferenceEngine.php
@@ -558,16 +558,15 @@ CONTROL;
 		}
 
 		// Load the new revision object
-		if( $this->mNewid ) {
-			$this->mNewRev = Revision::newFromId( $this->mNewid );
-		} else {
-			$this->mNewRev = Revision::newFromTitle( $this->mTitle );
-		}
-
-		if( is_null( $this->mNewRev ) ) {
+		$this->mNewRev = $this->mNewid
+			? Revision::newFromId( $this->mNewid )
+			: Revision::newFromTitle( $this->mTitle );
+		if( !$this->mNewRev instanceof Revision )
 			return false;
-		}
-
+		
+		// Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
+		$this->mNewid = $this->mNewRev->getId();
+		
 		// Set assorted variables
 		$timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
 		$this->mNewPage = $this->mNewRev->getTitle();
@@ -616,7 +615,8 @@ CONTROL;
 			$oldEdit = $this->mOldPage->escapeLocalUrl( 'action=edit&oldid=' . $this->mOldid );
 			$this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) )
 				. "</a> (<a href='$oldEdit'>" . htmlspecialchars( wfMsg( 'editold' ) ) . "</a>)";
-			//now that we considered old rev, we can make undo link (bug 8133, multi-edit undo)
+			
+			// Add an "undo" link
 			$newUndo = $this->mNewPage->escapeLocalUrl( 'action=edit&undoafter=' . $this->mOldid . '&undo=' . $this->mNewid);
 			$this->mNewtitle .= " (<a href='$newUndo'>" . htmlspecialchars( wfMsg( 'editundo' ) ) . "</a>)";
 		}
-- 
2.20.1