server/posts: fix post relations

Trying to relate post to itself resulted in 500 ISE.

1 files changed, 2 insertions, 0 deletions

diff --git a/server/szurubooru/func/posts.py b/server/szurubooru/func/posts.py
index 6ff3a87..d190b8d 100644
--- a/server/szurubooru/func/posts.py
+++ b/server/szurubooru/func/posts.py
@@ -377,6 +377,8 @@ def update_post_relations(post, new_post_ids):
         .all()
     if len(new_posts) != len(new_post_ids):
         raise InvalidPostRelationError('One of relations does not exist.')
+    if post.post_id in new_post_ids:
+        raise InvalidPostRelationError('Post cannot relate to itself.')
 
     relations_to_del = [p for p in old_posts if p.post_id not in new_post_ids]
     relations_to_add = [p for p in new_posts if p.post_id not in old_post_ids]