Ensure correct visibility handling for Undo and Follow requests (#1988)

Author: pfefferle

.github/changelog/1988-from-description

@@ -0,0 +1,4 @@
+Significance: patch
+Type: fixed
+
+Ensure correct visibility handling for `Undo` and `Follow` requests

includes/collection/class-following.php

@@ -89,7 +89,7 @@ public static function follow( $post, $user_id ) {
 			$follow->set_object( $post->guid );
 			$follow->set_to( array( $post->guid ) );
 
-			return add_to_outbox( $follow, null, $user_id );
+			return add_to_outbox( $follow, null, $user_id, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE );
 		}
 
 		return $post;

includes/collection/class-outbox.php

@@ -180,7 +180,9 @@ public static function undo( $outbox_item ) {
 			$type = 'Remove';
 		}
 
-		return add_to_outbox( $activity, $type, $outbox_item->post_author );
+		$visibility = \get_post_meta( $outbox_item->ID, 'activitypub_content_visibility', true );
+
+		return add_to_outbox( $activity, $type, $outbox_item->post_author, $visibility );
 	}
 
 	/**