From 8e3e785f5c31215fa9f5cec03a03245b136b5842 Mon Sep 17 00:00:00 2001
From: Youngtaek Yoon <noreply@yoon.anonaddy.me>
Date: Mon, 10 Apr 2023 19:26:59 +0900
Subject: [PATCH] Revert "fix: return nil where the parent not exists in
 x/collection Query/Parent (#955)"

This reverts commit d562b43025ce4c354e87f6b0ed60a09ec594e9a7.
---
 x/collection/keeper/grpc_query.go      |  2 +-
 x/collection/keeper/grpc_query_test.go | 14 +++++---------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/x/collection/keeper/grpc_query.go b/x/collection/keeper/grpc_query.go
index 131fb14485..6a282e9a89 100644
--- a/x/collection/keeper/grpc_query.go
+++ b/x/collection/keeper/grpc_query.go
@@ -534,7 +534,7 @@ func (s queryServer) Parent(c context.Context, req *collection.QueryParentReques
 
 	parent, err := s.keeper.GetParent(ctx, req.ContractId, req.TokenId)
 	if err != nil {
-		return nil, nil
+		return nil, err
 	}
 
 	token, err := s.keeper.GetNFT(ctx, req.ContractId, *parent)
diff --git a/x/collection/keeper/grpc_query_test.go b/x/collection/keeper/grpc_query_test.go
index a5c6f25bc6..8d8966268c 100644
--- a/x/collection/keeper/grpc_query_test.go
+++ b/x/collection/keeper/grpc_query_test.go
@@ -790,18 +790,9 @@ func (s *KeeperTestSuite) TestQueryParent() {
 			tokenID:    tokenID,
 			valid:      true,
 			postTest: func(res *collection.QueryParentResponse) {
-				s.Require().NotNil(res)
 				s.Require().Equal(collection.NewNFTID(s.nftClassID, 1), res.Parent.TokenId)
 			},
 		},
-		"valid request with no parent": {
-			contractID: s.contractID,
-			tokenID:    collection.NewNFTID(s.nftClassID, 1),
-			valid:      true,
-			postTest: func(res *collection.QueryParentResponse) {
-				s.Require().Nil(res)
-			},
-		},
 		"invalid contract id": {
 			tokenID: tokenID,
 		},
@@ -816,6 +807,10 @@ func (s *KeeperTestSuite) TestQueryParent() {
 			contractID: s.contractID,
 			tokenID:    collection.NewNFTID("deadbeef", 1),
 		},
+		"no parent": {
+			contractID: s.contractID,
+			tokenID:    collection.NewNFTID(s.nftClassID, 1),
+		},
 	}
 
 	for name, tc := range testCases {
@@ -830,6 +825,7 @@ func (s *KeeperTestSuite) TestQueryParent() {
 				return
 			}
 			s.Require().NoError(err)
+			s.Require().NotNil(res)
 			tc.postTest(res)
 		})
 	}