From cb696c95b495870cd615173ddd74ea243ce6f5d9 Mon Sep 17 00:00:00 2001
From: Skima Harvey <64636974+skimaharvey@users.noreply.github.com>
Date: Thu, 11 Jan 2024 09:22:44 +0000
Subject: [PATCH] fix: add existence check before the _beforeTokenTransfer hook
 (#844)

Co-authored-by: Jean Cvllr <31145285+CJ42@users.noreply.github.com>
---
 .../LSP8IdentifiableDigitalAssetCore.sol                     | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/contracts/LSP8IdentifiableDigitalAsset/LSP8IdentifiableDigitalAssetCore.sol b/contracts/LSP8IdentifiableDigitalAsset/LSP8IdentifiableDigitalAssetCore.sol
index 54e1a2350..89f57b15d 100644
--- a/contracts/LSP8IdentifiableDigitalAsset/LSP8IdentifiableDigitalAssetCore.sol
+++ b/contracts/LSP8IdentifiableDigitalAsset/LSP8IdentifiableDigitalAssetCore.sol
@@ -507,6 +507,11 @@ abstract contract LSP8IdentifiableDigitalAssetCore is
             revert LSP8CannotSendToAddressZero();
         }
 
+        // Check that `tokenId` is not already minted
+        if (_exists(tokenId)) {
+            revert LSP8TokenIdAlreadyMinted(tokenId);
+        }
+
         _beforeTokenTransfer(address(0), to, tokenId, data);
 
         // Check that `tokenId` was not minted inside the `_beforeTokenTransfer` hook