Index: includes/User.php
===================================================================
--- includes/User.php	(revision 3068)
+++ includes/User.php	(working copy)
@@ -69,6 +69,7 @@
 		'enotifwatchlistpages',
 		'enotifusertalkpages',
 		'enotifminoredits',
+		'enotifshowdiff',
 		'enotifrevealaddr',
 		'shownumberswatching',
 		'fancysig',
Index: includes/UserMailer.php
===================================================================
--- includes/UserMailer.php	(revision 3068)
+++ includes/UserMailer.php	(working copy)
@@ -205,6 +205,7 @@
 		# we use $wgEmergencyContact as sender's address
 		global $wgUser, $wgEnotifWatchlist;
 		global $wgEnotifMinorEdits, $wgEnotifUserTalk, $wgShowUpdatedMarker;
+		global $wgEnotifShowDiff;
 
 		$fname = 'UserMailer::notifyOnPageChange';
 		wfProfileIn( $fname );
@@ -298,7 +299,7 @@
 			# FIXME what do we do on failure ?
 		}
 		wfProfileOut( $fname );
-	} # function NotifyOnChange
+	} # function NotifyOnPageChange
 
 	/**
 	 * @private
@@ -401,7 +402,7 @@
 	 * @private
 	 */
 	function composeAndSendPersonalisedMail( $watchingUser ) {
-		global $wgLang;
+		global $wgLang, $wgTitle, $wgTmpDirectory, $wgEmailDiffCommand;
 		// From the PHP manual:
 		//     Note:  The to parameter cannot be an address in the form of "Something <someone@example.com>".
 		//     The mail command will not parse this properly while talking with the MTA.
@@ -417,6 +418,51 @@
 			$wgLang->timeanddate( $this->timestamp, true, false, $timecorrection ),
 			$body);
 
+		## Does this user require a diff?
+		if ($watchingUser->getOption('enotifshowdiff')) {
+			## Have we created one yet?
+			if (! isset($this->diff)) {
+				## New text:
+				$newrev = Revision::newFromTitle( $wgTitle );
+				if (!$newrev) {
+					$this->diff = ''; ## An image for example
+				}
+				else {
+					$newtext = $newrev->getText();
+					if (!$this->oldid) {
+						$this->diff = "This is a new page:\n$newtext\n";
+					}
+					else {
+						$newfile = tempnam($wgTempDirectory, "mediawikidiff2");
+						$fh = fopen($newfile, "w") or die("Could not open file $newfile");
+						fputs($fh, "$newtext\n");
+						fclose($fh);
+
+						## Old text:
+						$oldrev = Revision::newFromId( $this->oldid );
+						$oldtext = $oldrev->getText();
+						$oldfile = tempnam($wgTempDirectory, "mediawikidiff1");
+						$fh = fopen($oldfile, "w") or die("Could not open file $oldfile");
+						fputs($fh, "$oldtext\n");
+						fclose($fh);
+
+						$differ = tempnam($wgTempDirectory, "mediawikidiff3");
+						$diffcom = str_replace(
+							array("OLDFILE","NEWFILE","DIFFFILE"),
+							array("$oldfile","$newfile","$differ"),
+							$wgEmailDiffCommand);
+						system($diffcom);
+						$difftext = file_get_contents($differ);
+						$this->diff = "\nVersion differences:\n$difftext\n";
+						unlink($oldfile); unlink($newfile); unlink($differ);
+					} ## end if have an oldid
+				} ## end if have a newrev
+			} ## end if don't have a diff yet
+		} ## end user requires a diff
+
+		$body = str_replace('$PAGEDIFF', isset($this->diff) ? $this->diff : '', $body);
+
+
 		$error = userMailer( $to, $this->from, $this->subject, $body, $this->replyto );
 		return ($error == '');
 	}
Index: includes/SpecialPreferences.php
===================================================================
--- includes/SpecialPreferences.php	(revision 3068)
+++ includes/SpecialPreferences.php	(working copy)
@@ -455,7 +455,7 @@
 		global $wgUser, $wgOut, $wgLang, $wgContLang;
 		global $wgAllowRealName, $wgImageLimits, $wgThumbLimits;
 		global $wgDisableLangConversion;
-		global $wgEnotifWatchlist, $wgEnotifUserTalk,$wgEnotifMinorEdits;
+		global $wgEnotifWatchlist, $wgEnotifUserTalk,$wgEnotifMinorEdits,$wgEnotifShowDiff;
 		global $wgRCShowWatchingUsers, $wgEnotifRevealEditorAddress;
 		global $wgEnableEmail, $wgEnableUserEmail, $wgEmailAuthentication;
 		global $wgContLanguageCode, $wgDefaultSkin, $wgSkipSkins, $wgAuth;
@@ -487,6 +487,7 @@
 		$this->mUsedToggles[ 'enotifwatchlistpages' ] = true;
 		$this->mUsedToggles[ 'enotifusertalkpages' ] = true;
 		$this->mUsedToggles[ 'enotifminoredits' ] = true;
+		$this->mUsedToggles[ 'enotifshowdiff' ] = true;
 		$this->mUsedToggles[ 'enotifrevealaddr' ] = true;
 		$this->mUsedToggles[ 'uselivepreview' ] = true;
 
@@ -526,6 +527,7 @@
 		$enotifusertalkpages = ($wgEnotifUserTalk) ? $this->getToggle( 'enotifusertalkpages', false, $disableEmailPrefs ) : '';
 		$enotifminoredits = ($wgEnotifWatchlist && $wgEnotifMinorEdits) ? $this->getToggle( 'enotifminoredits', false, $disableEmailPrefs ) : '';
 		$enotifrevealaddr = (($wgEnotifWatchlist || $wgEnotifUserTalk) && $wgEnotifRevealEditorAddress) ? $this->getToggle( 'enotifrevealaddr', false, $disableEmailPrefs ) : '';
+		$enotifshowdiff = ($wgEnotifWatchlist && $wgEnotifShowDiff) ? $this->getToggle( 'enotifshowdiff' ) : '';
 		$prefs_help_email_enotif = ( $wgEnotifWatchlist || $wgEnotifUserTalk) ? ' ' . wfMsg('prefs-help-email-enotif') : '';
 		$prefs_help_realname = '';
 
@@ -685,6 +687,7 @@
 					$enotifrevealaddr.
 					$enotifwatchlistpages.
 					$enotifusertalkpages.
+					$enotifshowdiff.	
 					$enotifminoredits );
 			if ($wgEnableUserEmail) {
 			$emf = wfMsg( 'allowemail' );
Index: includes/DefaultSettings.php
===================================================================
--- includes/DefaultSettings.php	(revision 3068)
+++ includes/DefaultSettings.php	(working copy)
@@ -424,6 +424,12 @@
 $wgEnableUserEmail = true;
 
 /**
+ * The command to create email diffs.
+ * @global string $wgEmailDiffCommand
+ */
+$wgEmailDiffCommand = "/usr/bin/diff -u OLDFILE NEWFILE | /usr/bin/tail +3 > DIFFFILE";
+
+/**
  * SMTP Mode
  * For using a direct (authenticated) SMTP server connection.
  * Default to false or fill an array :
@@ -1067,9 +1073,11 @@
 $wgEnotifUserTalk		= false;	# UPO
 $wgEnotifRevealEditorAddress	= false;	# UPO; reply-to address may be filled with page editor's address (if user allowed this in the preferences)
 $wgEnotifMinorEdits		= true;	# UPO; false: "minor edits" on pages do not trigger notification mails.
-#							# Attention: _every_ change on a user_talk page trigger a notification mail (if the user is not yet notified)
+$wgEnotifShowDiff = true; # UPO; if set, email notifications contain textual diffs
 
+#							# Attention: _every_ change on a user_talk page triggers a notification mail (if the user is not yet notified)
 
+
 /** Show watching users in recent changes, watchlist and page history views */
 $wgRCShowWatchingUsers 				= false; # UPO
 /** Show watching users in Page views */
@@ -1606,6 +1614,7 @@
 	'enotifwatchlistpages' 	=> 0,
 	'enotifusertalkpages' 	=> 1,
 	'enotifminoredits' 	=> 0,
+	'enotifshowdiff' 	=> 0,
 	'enotifrevealaddr' 	=> 0,
 	'shownumberswatching' 	=> 1,
 	'fancysig' 		=> 0,
Index: languages/messages/MessagesEn.php
===================================================================
--- languages/messages/MessagesEn.php	(revision 3068)
+++ languages/messages/MessagesEn.php	(working copy)
@@ -358,6 +358,7 @@
 'tog-enotifwatchlistpages' 	=> 'E-mail me when a page I\'m watching is changed',
 'tog-enotifusertalkpages' 	=> 'E-mail me when my user talk page is changed',
 'tog-enotifminoredits' 		=> 'E-mail me also for minor edits of pages',
+'tog-enotifshowdiff' 		=> 'Send a diff in the change email',
 'tog-enotifrevealaddr' 		=> 'Reveal my e-mail address in notification mails',
 'tog-shownumberswatching' 	=> 'Show the number of watching users',
 'tog-fancysig' => 'Raw signatures (without automatic link)',
@@ -1464,14 +1465,15 @@
 'created'			=> 'created',
 'enotif_subject' 	=> '{{SITENAME}} page $PAGETITLE has been $CHANGEDORCREATED by $PAGEEDITOR',
 'enotif_lastvisited' => 'See $1 for all changes since your last visit.',
-'enotif_body' => 'Dear $WATCHINGUSERNAME,
+'enotif_body' => 'Dear $WATCHINGUSERNAME:
 
-the {{SITENAME}} page $PAGETITLE has been $CHANGEDORCREATED on $PAGEEDITDATE by $PAGEEDITOR, see $PAGETITLE_URL for the current version.
+The {{SITENAME}} page $PAGETITLE has been $CHANGEDORCREATED on $PAGEEDITDATE by $PAGEEDITOR, see $PAGETITLE_URL for the current version.
 
 $NEWPAGE
 
 Editor\'s summary: $PAGESUMMARY $PAGEMINOREDIT
 
+$PAGEDIFF
 Contact the editor:
 mail: $PAGEEDITOR_EMAIL
 wiki: $PAGEEDITOR_WIKI