fix for unit tests: do not call NewAccessWitness in NewEVMTxContext (#49)

* potential fix: do not call NewAccessWitness in NewEVMTxContext

* more fixes: check for the existence of Accesses

* fix absence of witness in copy

* fix another witness issue

* workaround: ensure the prefetcher is off in verkle mode

* fix the remaining issues in tests

* review feedback

* fix witness allocation in stateless test

Author: gballet

consensus/ethash/consensus.go

@@ -671,9 +671,8 @@ func accumulateRewards(config *params.ChainConfig, state *state.StateDB, header
 		r.Div(blockReward, big32)
 		reward.Add(reward, r)
 	}
-	coinbase := utils.GetTreeKeyBalance(header.Coinbase.Bytes())
-
-	if state.Witness() != nil {
+	if config.IsCancun(header.Number) {
+		coinbase := utils.GetTreeKeyBalance(header.Coinbase.Bytes())
 		state.Witness().TouchAddress(coinbase, state.GetBalance(header.Coinbase).Bytes())
 	}
 	state.AddBalance(header.Coinbase, reward)

core/evm.go

@@ -69,7 +69,6 @@ func NewEVMTxContext(msg Message) vm.TxContext {
 	return vm.TxContext{
 		Origin:   msg.From(),
 		GasPrice: new(big.Int).Set(msg.GasPrice()),
-		Accesses: types.NewAccessWitness(),
 	}
 }
 

core/state/statedb.go

@@ -148,12 +148,14 @@ func New(root common.Hash, db Database, snaps *snapshot.Tree) (*StateDB, error)
 		journal:             newJournal(),
 		accessList:          newAccessList(),
 		hasher:              crypto.NewKeccakState(),
-		witness:             types.NewAccessWitness(),
 	}
-	if sdb.snaps == nil && tr.IsVerkle() {
-		sdb.snaps, err = snapshot.New(db.TrieDB().DiskDB(), db.TrieDB(), 1, root, false, true, false, true)
-		if err != nil {
-			return nil, err
+	if tr.IsVerkle() {
+		sdb.witness = types.NewAccessWitness()
+		if sdb.snaps == nil {
+			sdb.snaps, err = snapshot.New(db.TrieDB().DiskDB(), db.TrieDB(), 1, root, false, true, false, true)
+			if err != nil {
+				return nil, err
+			}
 		}
 	}
 	if sdb.snaps != nil {
@@ -182,7 +184,7 @@ func (s *StateDB) StartPrefetcher(namespace string) {
 		s.prefetcher.close()
 		s.prefetcher = nil
 	}
-	if s.snap != nil {
+	if s.snap != nil && !s.trie.IsVerkle() {
 		s.prefetcher = newTriePrefetcher(s.db, s.originalRoot, namespace)
 	}
 }
@@ -713,7 +715,9 @@ func (s *StateDB) Copy() *StateDB {
 		preimages:           make(map[common.Hash][]byte, len(s.preimages)),
 		journal:             newJournal(),
 		hasher:              crypto.NewKeccakState(),
-		witness:             s.witness.Copy(),
+	}
+	if s.witness != nil {
+		state.witness = s.witness.Copy()
 	}
 	// Copy the dirty states, logs, and preimages
 	for addr := range s.journal.dirties {

core/state_processor.go

@@ -95,6 +95,9 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 func applyTransaction(msg types.Message, config *params.ChainConfig, bc ChainContext, author *common.Address, gp *GasPool, statedb *state.StateDB, blockNumber *big.Int, blockHash common.Hash, tx *types.Transaction, usedGas *uint64, evm *vm.EVM) (*types.Receipt, error) {
 	// Create a new context to be used in the EVM environment.
 	txContext := NewEVMTxContext(msg)
+	if config.IsCancun(blockNumber) {
+		txContext.Accesses = types.NewAccessWitness()
+	}
 	evm.Reset(txContext, statedb)
 
 	// Apply the transaction to the current state (included in the env).

core/vm/evm.go

@@ -130,7 +130,7 @@ type EVM struct {
 // NewEVM returns a new EVM. The returned EVM is not thread safe and should
 // only ever be used *once*.
 func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig *params.ChainConfig, config Config) *EVM {
-	if txCtx.Accesses == nil {
+	if txCtx.Accesses == nil && chainConfig.IsCancun(blockCtx.BlockNumber) {
 		txCtx.Accesses = types.NewAccessWitness()
 	}
 	evm := &EVM{

miner/worker_test.go

@@ -267,10 +267,7 @@ func testGenerateBlockAndImport(t *testing.T, isClique bool) {
 			if _, err := chain.InsertChain([]*types.Block{block}); err != nil {
 				t.Fatalf("failed to insert new mined block %d: %v", block.NumberU64(), err)
 			}
-		// TODO(gballet) the timeout had to be increased from 3s to 7s with verkle
-		// trees, presumably because calculating an address is orders of magnitude
-		// slower with perdersen_hash not using the multi-exponentiation.
-		case <-time.After(5 * time.Second): // Worker needs 1s to include new changes.
+		case <-time.After(3 * time.Second): // Worker needs 1s to include new changes.
 			t.Fatalf("timeout")
 		}
 	}