core/rawdb: add test

core/rawdb/accessors_chain.go

@@ -737,6 +737,9 @@ func writeAncientBlock(op ethdb.AncientWriteOp, block *types.Block, header *type
 	return nil
 }
 
+// WriteAncientHeaderChain writes the supplied headers along with nil block
+// bodies and receipts into the ancient store. It's supposed to be used for
+// storing chain segment before the chain cutoff.
 func WriteAncientHeaderChain(db ethdb.AncientWriter, headers []*types.Header) (int64, error) {
 	return db.ModifyAncients(func(op ethdb.AncientWriteOp) error {
 		for _, header := range headers {

core/rawdb/accessors_chain_test.go

@@ -464,6 +464,48 @@ func TestAncientStorage(t *testing.T) {
 	}
 }
 
+func TestWriteAncientHeaderChain(t *testing.T) {
+	db, err := NewDatabaseWithFreezer(NewMemoryDatabase(), t.TempDir(), "", false)
+	if err != nil {
+		t.Fatalf("failed to create database with ancient backend")
+	}
+	defer db.Close()
+
+	// Create a test block
+	var headers []*types.Header
+	headers = append(headers, &types.Header{
+		Number:      big.NewInt(0),
+		Extra:       []byte("test block"),
+		UncleHash:   types.EmptyUncleHash,
+		TxHash:      types.EmptyTxsHash,
+		ReceiptHash: types.EmptyReceiptsHash,
+	})
+	headers = append(headers, &types.Header{
+		Number:      big.NewInt(1),
+		Extra:       []byte("test block"),
+		UncleHash:   types.EmptyUncleHash,
+		TxHash:      types.EmptyTxsHash,
+		ReceiptHash: types.EmptyReceiptsHash,
+	})
+	// Write and verify the header in the database
+	WriteAncientHeaderChain(db, headers)
+
+	for _, header := range headers {
+		if blob := ReadHeaderRLP(db, header.Hash(), header.Number.Uint64()); len(blob) == 0 {
+			t.Fatalf("no header returned")
+		}
+		if h := ReadCanonicalHash(db, header.Number.Uint64()); h != header.Hash() {
+			t.Fatalf("no canonical hash returned")
+		}
+		if blob := ReadBodyRLP(db, header.Hash(), header.Number.Uint64()); len(blob) != 0 {
+			t.Fatalf("unexpected body returned")
+		}
+		if blob := ReadReceiptsRLP(db, header.Hash(), header.Number.Uint64()); len(blob) != 0 {
+			t.Fatalf("unexpected body returned")
+		}
+	}
+}
+
 func TestCanonicalHashIteration(t *testing.T) {
 	var cases = []struct {
 		from, to uint64

eth/downloader/beaconsync.go

@@ -17,7 +17,6 @@
 package downloader
 
 import (
-	"errors"
 	"fmt"
 	"sync"
 	"time"
@@ -308,7 +307,7 @@ func (d *Downloader) fetchHeaders(from uint64) error {
 			}
 		}
 		if h == nil {
-			return errors.New("header at chain cutoff is not available")
+			return fmt.Errorf("header at chain cutoff is not available, cutoff: %d", d.chainCutoffNumber)
 		}
 		if h.Hash() != d.chainCutoffHash {
 			return fmt.Errorf("header at chain cutoff mismatched, want: %v, got: %v", d.chainCutoffHash, h.Hash())