From 3ccd6b6dbb462755079dc8394b5c141ef397486c Mon Sep 17 00:00:00 2001
From: Sina Mahmoodi <1591639+s1na@users.noreply.github.com>
Date: Wed, 5 Jan 2022 16:22:46 +0100
Subject: [PATCH] graphql: fix block resolving for parent field (#24191)

Fixes #24161
---
 graphql/graphql.go | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/graphql/graphql.go b/graphql/graphql.go
index 3e23f41f7..16e0eb654 100644
--- a/graphql/graphql.go
+++ b/graphql/graphql.go
@@ -599,21 +599,18 @@ func (b *Block) BaseFeePerGas(ctx context.Context) (*hexutil.Big, error) {
 }
 
 func (b *Block) Parent(ctx context.Context) (*Block, error) {
-	// If the block header hasn't been fetched, and we'll need it, fetch it.
-	if b.numberOrHash == nil && b.header == nil {
-		if _, err := b.resolveHeader(ctx); err != nil {
-			return nil, err
-		}
+	if _, err := b.resolveHeader(ctx); err != nil {
+		return nil, err
 	}
-	if b.header != nil && b.header.Number.Uint64() > 0 {
-		num := rpc.BlockNumberOrHashWithNumber(rpc.BlockNumber(b.header.Number.Uint64() - 1))
-		return &Block{
-			backend:      b.backend,
-			numberOrHash: &num,
-			hash:         b.header.ParentHash,
-		}, nil
+	if b.header == nil || b.header.Number.Uint64() < 1 {
+		return nil, nil
 	}
-	return nil, nil
+	num := rpc.BlockNumberOrHashWithNumber(rpc.BlockNumber(b.header.Number.Uint64() - 1))
+	return &Block{
+		backend:      b.backend,
+		numberOrHash: &num,
+		hash:         b.header.ParentHash,
+	}, nil
 }
 
 func (b *Block) Difficulty(ctx context.Context) (hexutil.Big, error) {