Fix thread deduplication pt. 2

1 files changed, 9 insertions, 6 deletions

diff --git a/backend/notes/note.go b/backend/notes/note.go
index 8a73b70..7ef537f 100644
--- a/backend/notes/note.go
+++ b/backend/notes/note.go
@@ -40,13 +40,16 @@ func isChainContained(smallChainPost, bigChainPost Note) bool {
 		return false
 	}
 
-	// check if parents of smallChainPost are included in bigChainPost
-	offset := len(bigChainPost.Parents) - len(smallChainPost.Parents)
-	for i, note := range smallChainPost.Parents {
-		if bigChainPost.Parents[offset+i].URI != note.URI {
-			return false
-		}
+	// if the thread is going to differ at any post, it's going to be at the end
+	// thus if the posts match their parents MUST match too
+	// (not that I expect to ever compare a post to itself but this way it won't break if I do. And technically a thread contains itself)
+	if len(smallChainPost.Parents) == len(bigChainPost.Parents) {
+		return smallChainPost.URI == bigChainPost.URI
 	}
+
+	// check if the last post of the smaller chain is the (n+1)-th post of the bigger chain
+	// where n is the number of parents in the smaller reply chain
+	offset := len(bigChainPost.Parents) - len(smallChainPost.Parents)
 	return smallChainPost.URI == bigChainPost.Parents[offset-1].URI
 }