From c0b8374783507816155084e498c38fe913b023ef Mon Sep 17 00:00:00 2001
From: Piotr Macek <4007944+piotrm50@users.noreply.github.com>
Date: Mon, 22 Apr 2024 11:26:03 +0200
Subject: [PATCH] Do not return EmptyBlockID as a shallow like parent.

---
 pkg/protocol/engine/tipselection/v1/tip_selection.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkg/protocol/engine/tipselection/v1/tip_selection.go b/pkg/protocol/engine/tipselection/v1/tip_selection.go
index da01c2c0c..a4820acbe 100644
--- a/pkg/protocol/engine/tipselection/v1/tip_selection.go
+++ b/pkg/protocol/engine/tipselection/v1/tip_selection.go
@@ -186,7 +186,12 @@ func (t *TipSelection) likedInsteadReferences(maxLikedInsteadReferencesPerParent
 			return ierrors.Errorf("transaction required for liked instead reference (%s) not found in mem-pool", likedSpenderID)
 		}
 
-		necessaryReferences[likedSpenderID] = lo.First(transactionMetadata.ValidAttachments())
+		validAttachments := transactionMetadata.ValidAttachments()
+		if len(validAttachments) == 0 {
+			return ierrors.Errorf("attachment of the transaction required for liked instead reference (%s) does not exist", likedSpenderID)
+		}
+
+		necessaryReferences[likedSpenderID] = lo.First(validAttachments)
 
 		return nil
 	}); err != nil {