From 1f6e0f168ceafcd254403b40f752a21b82e8d923 Mon Sep 17 00:00:00 2001
From: Hypolite Petovan <hypolite@mrpetovan.com>
Date: Sun, 24 Feb 2019 15:48:56 -0500
Subject: [PATCH] Add missing author contact in ActivityPub\Processor

- Add logging for future occurrences
- Addresses https://github.com/friendica/friendica/issues/6338#issuecomment-466812104
---
 src/Protocol/ActivityPub/Processor.php | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/Protocol/ActivityPub/Processor.php b/src/Protocol/ActivityPub/Processor.php
index 2661444e0..e5ef354ba 100644
--- a/src/Protocol/ActivityPub/Processor.php
+++ b/src/Protocol/ActivityPub/Processor.php
@@ -669,13 +669,16 @@ class Processor
 
 		$parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 
-		$implicit_mentions = [
-			$parent_author['url'],
-			$parent_author['nurl'],
-			$parent_author['alias'],
-		];
+		$implicit_mentions = [];
+		if (empty($parent_author)) {
+			Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
+		}else {
+			$implicit_mentions[] = $parent_author['url'];
+			$implicit_mentions[] = $parent_author['nurl'];
+			$implicit_mentions[] = $parent_author['alias'];
+		}
 
-		if ($parent['alias']) {
+		if (!empty($parent['alias'])) {
 			$implicit_mentions[] = $parent['alias'];
 		}