eth, les: add error when accessing missing block state (#18346)

This change makes getBalance, getCode, getStorageAt, getProof,
call, getTransactionCount return an error if the block number in
the request doesn't exist. getHeaderByNumber still returns null
for missing headers.

1 files changed, 5 insertions, 1 deletions

diff --git a/les/api_backend.go b/les/api_backend.go
index 4fe352136..589cf572d 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -18,6 +18,7 @@ package les
 
 import (
 	"context"
+	"errors"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -78,9 +79,12 @@ func (b *LesApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 
 func (b *LesApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
 	header, err := b.HeaderByNumber(ctx, blockNr)
-	if header == nil || err != nil {
+	if err != nil {
 		return nil, nil, err
 	}
+	if header == nil {
+		return nil, nil, errors.New("header not found")
+	}
 	return light.NewState(ctx, header, b.eth.odr), header, nil
 }