From 91026c2542671a06103cb3c1b7869d411a178795 Mon Sep 17 00:00:00 2001
From: Chad Horohoe <demon@users.mediawiki.org>
Date: Wed, 1 Sep 2010 14:16:23 +0000
Subject: [PATCH] Don't show "older edit" when no older edit available. Based
 on patch by Umherirrender

---
 RELEASE-NOTES                         |  1 +
 includes/diff/DifferenceInterface.php | 28 +++++++++++++++------------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 90532746f9..b3f45dc664 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -310,6 +310,7 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
   when a resource limit such as $wgMaxShellMemory is hit.
 * (bug 24981) Allow extensions to access SpecialUpload variables again
 * (bug 20744) Wiki forgets about an uploaded file
+* (bug 17913) Don't show "older edit" when no older edit available
 
 === API changes in 1.17 ===
 * (bug 22738) Allow filtering by action type on query=logevent.
diff --git a/includes/diff/DifferenceInterface.php b/includes/diff/DifferenceInterface.php
index 9cbee31a09..3b7e3ed97f 100644
--- a/includes/diff/DifferenceInterface.php
+++ b/includes/diff/DifferenceInterface.php
@@ -277,18 +277,22 @@ CONTROL;
 		if( $this->unhide ) {
 			$query['unhide'] = 1;
 		}
-		$prevlink = $sk->link(
-			$this->mTitle,
-			wfMsgHtml( 'previousdiff' ),
-			array(
-				'id' => 'differences-prevlink'
-			),
-			$query,
-			array(
-				'known',
-				'noclasses'
-			)
-		);
+		if( !$this->mOldRev->getPrevious() ) {
+			$prevlink = '&#160;';
+		} else {
+			$prevlink = $sk->link(
+				$this->mTitle,
+				wfMsgHtml( 'previousdiff' ),
+				array(
+					'id' => 'differences-prevlink'
+				),
+				$query,
+				array(
+					'known',
+					'noclasses'
+				)
+			);
+		}
 
 		# Make "next revision link"
 		$query['diff'] = 'next';
-- 
2.20.1