From 71eacf3fad2c6c256ef545696251e2891e3f4bf3 Mon Sep 17 00:00:00 2001
From: Roan Kattouw <roan.kattouw@gmail.com>
Date: Mon, 23 May 2016 12:22:41 -0700
Subject: [PATCH] Add diff link to page-linked notification

Will only show for new instances, because the information
will be unavailable for old ones.

Bug: T135959
Depends-On: I3d894acaf3d85b790e5034c7d9f76bf94672f445
Change-Id: I04620678dd0ebffb3b1a92a9a0587cb7557d77f4
---
 Hooks.php                                         |  3 +++
 .../formatters/PageLinkedPresentationModel.php    | 15 ++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Hooks.php b/Hooks.php
index 2d9dd8577..640778150 100644
--- a/Hooks.php
+++ b/Hooks.php
@@ -684,6 +684,8 @@ class EchoHooks {
 			$user = $wgUser;
 		}
 
+		$revid = $linksUpdate->getRevision() ? $linksUpdate->getRevision()->getId() : null;
+
 		// link notification is boundless as you can include infinite number of links in a page
 		// db insert is expensive, limit it to a reasonable amount, we can increase this limit
 		// once the storage is on Redis
@@ -703,6 +705,7 @@ class EchoHooks {
 					'agent' => $user,
 					'extra' => array(
 						'link-from-page-id' => $linksUpdate->mTitle->getArticleId(),
+						'revid' => $revid,
 					)
 				) );
 				$max--;
diff --git a/includes/formatters/PageLinkedPresentationModel.php b/includes/formatters/PageLinkedPresentationModel.php
index 6d7567112..bc3404275 100644
--- a/includes/formatters/PageLinkedPresentationModel.php
+++ b/includes/formatters/PageLinkedPresentationModel.php
@@ -34,7 +34,20 @@ class EchoPageLinkedPresentationModel extends EchoEventPresentationModel {
 			'icon' => 'linked',
 			'prioritized' => true
 		);
-		return array( $whatLinksHereLink );
+
+		$revid = $this->event->getExtraParam( 'revid' );
+		$diffLink = null;
+		if ( $revid !== null ) {
+			$diffLink = array(
+				'url' => $this->event->getTitle()->getFullURL( array( 'diff' => $revid, 'oldid' => 'prev' ) ),
+				'label' => $this->msg( 'notification-link-text-view-changes' )->text(),
+				'description' => '',
+				'icon' => 'changes',
+				'prioritized' => true
+			);
+		}
+
+		return array( $whatLinksHereLink, $diffLink );
 	}
 
 	protected function getHeaderMessageKey() {