make InsertChain return an error when stopped due to l2 migration block

core/blockchain.go

@@ -1882,6 +1882,9 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, er
 		// If the chain is terminating, stop processing blocks
 		if bc.insertStopped() {
 			log.Debug("Abort during block processing")
+			if bc.Config().IsL2Migration(block.Number()) {
+				err = errInsertionInterrupted
+			}
 			break
 		}
 		// If the header is a banned one, straight out abort

core/blockchain_test.go

@@ -38,6 +38,7 @@ import (
 	"github.com/celo-org/celo-blockchain/ethdb"
 	"github.com/celo-org/celo-blockchain/params"
 	"github.com/celo-org/celo-blockchain/trie"
+	"github.com/stretchr/testify/require"
 )
 
 // So we can deterministically seed different blockchains
@@ -205,6 +206,25 @@ func TestLastBlock(t *testing.T) {
 	}
 }
 
+func TestNoInsertPastL2MigrationBlock(t *testing.T) {
+	_, blockchain, err := newCanonical(mockEngine.NewFaker(), 0, true)
+	if err != nil {
+		t.Fatalf("failed to create pristine chain: %v", err)
+	}
+	defer blockchain.Stop()
+
+	migrationBlock := 2
+	blockchain.chainConfig.L2MigrationBlock = big.NewInt(int64(migrationBlock))
+
+	blocks := makeBlockChain(blockchain.CurrentBlock(), 100, mockEngine.NewFullFaker(), blockchain.db, 0)
+	failedBlock, err := blockchain.InsertChain(blocks)
+	require.EqualError(t, err, errInsertionInterrupted.Error())
+	require.EqualValues(t, migrationBlock-1, failedBlock)
+	if blocks[migrationBlock-2].Hash() != rawdb.ReadHeadBlockHash(blockchain.db) {
+		t.Fatalf("Write/Get HeadBlockHash failed")
+	}
+}
+
 // Tests that given a starting canonical chain of a given size, it can be extended
 // with various length chains.
 func TestExtendCanonicalHeaders(t *testing.T) { testExtendCanonical(t, false) }