object/tree: Reject duplicates

1 files changed, 7 insertions, 0 deletions

diff --git a/object/tree/parse.go b/object/tree/parse.go
index b1069918..90519705 100644
--- a/object/tree/parse.go
+++ b/object/tree/parse.go
@@ -17,6 +17,7 @@ import (
 func Parse(body []byte, objectFormat id.ObjectFormat) (*Tree, error) {
 	tree := new(Tree)
 	idSize := objectFormat.Size()
+	seen := make(map[string]struct{})
 
 	i := 0
 	for i < len(body) {
@@ -65,6 +66,12 @@ func Parse(body []byte, objectFormat id.ObjectFormat) (*Tree, error) {
 			}
 		}
 
+		if _, dup := seen[entry.Name]; dup {
+			return nil, fmt.Errorf("%w: duplicate entry name %q", ErrInvalidTree, entry.Name)
+		}
+
+		seen[entry.Name] = struct{}{}
+
 		tree.entries = append(tree.entries, entry)
 	}