also discard Add/Remove at the AP side

(cherry picked from commit 2aee659cbdd147eca1c49385ea867ea11d2a72e5)

Co-authored-by: Mario Vavti <mario@mariovavti.com>

2 files changed, 22 insertions, 7 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 22a68d1e0..0c75d0507 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+Hubzilla 9.4.3 (2024-10-10)
+	- Discard Add/Remove activities (Hubzilla 10 and (streams) compatibility)
+
+
 Hubzilla 9.4.2 (2024-10-04)
 	- Indicate reacted state via icon color (community wish)
 	- Fix modal backdrop not removed when reacting from the modal
diff --git a/Zotlabs/Lib/Activity.php b/Zotlabs/Lib/Activity.php
index 1ea42acd3..90d7af8e8 100644
--- a/Zotlabs/Lib/Activity.php
+++ b/Zotlabs/Lib/Activity.php
@@ -3054,13 +3054,6 @@ class Activity {
 			}
 
 			$a = new ActivityStreams($n);
-			if ($a->type === 'Announce' && is_array($a->obj)
-				&& array_key_exists('object', $a->obj) && array_key_exists('actor', $a->obj)) {
-				// This is a relayed/forwarded Activity (as opposed to a shared/boosted object)
-				// Reparse the encapsulated Activity and use that instead
-				logger('relayed activity', LOGGER_DEBUG);
-				$a = new ActivityStreams($a->obj);
-			}
 
 			logger($a->debug(), LOGGER_DATA);
 
@@ -3069,6 +3062,24 @@ class Activity {
 				break;
 			}
 
+			if (in_array($a->type, ['Add', 'Remove'])
+				&& is_array($a->obj)
+				&& array_key_exists('object', $a->obj)
+				&& array_key_exists('actor', $a->obj)
+				&& !empty($a->tgt)) {
+
+				logger('unsupported collection operation', LOGGER_DEBUG);
+				return;
+			}
+
+			if ($a->type === 'Announce' && is_array($a->obj)
+				&& array_key_exists('object', $a->obj) && array_key_exists('actor', $a->obj)) {
+				// This is a relayed/forwarded Activity (as opposed to a shared/boosted object)
+				// Reparse the encapsulated Activity and use that instead
+				logger('relayed activity', LOGGER_DEBUG);
+				$a = new ActivityStreams($a->obj);
+			}
+
 			$item = Activity::decode_note($a);
 
 			if (!$item) {