From 597c5d38e9a4c0bc737333c9e51907da3eefa83b Mon Sep 17 00:00:00 2001
From: Sina Mahmoodi <itz.s1na@gmail.com>
Date: Tue, 4 Jan 2022 18:33:12 +0100
Subject: [PATCH] graphql: check header first in blocks query

---
 graphql/graphql.go | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/graphql/graphql.go b/graphql/graphql.go
index e92f1126f66..711989412b7 100644
--- a/graphql/graphql.go
+++ b/graphql/graphql.go
@@ -1110,10 +1110,21 @@ func (r *Resolver) Blocks(ctx context.Context, args struct {
 	ret := make([]*Block, 0, to-from+1)
 	for i := from; i <= to; i++ {
 		numberOrHash := rpc.BlockNumberOrHashWithNumber(i)
-		ret = append(ret, &Block{
+		block := &Block{
 			backend:      r.backend,
 			numberOrHash: &numberOrHash,
-		})
+		}
+		// Resolve the header to check for existence.
+		// Note we don't resolve block directly here since it will require an
+		// additional network request for light client.
+		h, err := block.resolveHeader(ctx)
+		if err != nil {
+			return nil, err
+		} else if h == nil {
+			// Blocks after must be non-existent too, break.
+			break
+		}
+		ret = append(ret, block)
 	}
 	return ret, nil
 }