don't update an event that hasn't changed.

include/event.php

@@ -213,6 +213,22 @@ function event_store($arr) {
 
 
 	if($arr['id']) {
+
+		// has the event actually changed?
+
+		$r = q("SELECT * FROM `event` WHERE `id` = %d AND `uid` = %d LIMIT 1",
+			intval($arr['id']),
+			intval($arr['uid'])
+		);
+		if((! count($r)) || ($r[0]['edited'] === $arr['edited'])) {
+			$r = q("SELECT * FROM `item` WHERE `event-id` = %d AND `uid` = %d LIMIT 1",
+				intval($arr['id']),
+				intval($arr['uid'])
+			);
+			return((count($r)) ? $r[0]['id'] : 0);
+		}
+
+
 		$r = q("UPDATE `event` SET
 			`edited` = '%s',
 			`start` = '%s',

include/items.php

@@ -1347,6 +1347,7 @@ function consume_feed($xml,$importer,&$contact, &$hub, $datedir = 0, $secure_fee
 					if(x($ev,'desc') && x($ev,'start')) {
 						$ev['uid'] = $importer['uid'];
 						$ev['uri'] = $item_id;
+						$ev['edited'] = $datarray['edited'];
 
 						if(is_array($contact))
 							$ev['cid'] = $contact['id'];

mod/dfrn_notify.php

@@ -676,6 +676,7 @@ function dfrn_notify_post(&$a) {
 					$ev['cid'] = $importer['id'];
 					$ev['uid'] = $importer['uid'];
 					$ev['uri'] = $item_id;
+					$ev['edited'] = $datarray['edited'];
 
 					$r = q("SELECT * FROM `event` WHERE `uri` = '%s' AND `uid` = %d LIMIT 1",
 						dbesc($item_id),