Merge 746755e415 into dab746b3ef

internal/ethapi/api.go

@@ -775,7 +775,7 @@ func (api *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockN
 //
 // Note, this function doesn't make any changes in the state/blockchain and is
 // useful to execute and retrieve values.
-func (api *BlockChainAPI) SimulateV1(ctx context.Context, opts simOpts, blockNrOrHash *rpc.BlockNumberOrHash) ([]map[string]interface{}, error) {
+func (api *BlockChainAPI) SimulateV1(ctx context.Context, opts simOpts, blockNrOrHash *rpc.BlockNumberOrHash) ([]*simBlockResult, error) {
 	if len(opts.BlockStateCalls) == 0 {
 		return nil, &invalidParamsError{message: "empty input"}
 	} else if len(opts.BlockStateCalls) > maxSimulateBlocks {

internal/ethapi/api_test.go

@@ -24,6 +24,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"math/big"
 	"os"
 	"path/filepath"
@@ -2309,6 +2310,101 @@ func TestSimulateV1(t *testing.T) {
 	}
 }
 
+func TestSimulateV1ChainLinkage(t *testing.T) {
+	var (
+		acc          = newTestAccount()
+		sender       = acc.addr
+		contractAddr = common.Address{0xaa, 0xaa}
+		recipient    = common.Address{0xbb, 0xbb}
+		gspec        = &core.Genesis{
+			Config: params.MergedTestChainConfig,
+			Alloc: types.GenesisAlloc{
+				sender:       {Balance: big.NewInt(params.Ether)},
+				contractAddr: {Code: common.Hex2Bytes("5f35405f8114600f575f5260205ff35b5f80fd")},
+			},
+		}
+		signer = types.LatestSigner(params.MergedTestChainConfig)
+	)
+	backend := newTestBackend(t, 1, gspec, beacon.New(ethash.NewFaker()), func(i int, b *core.BlockGen) {
+		tx := types.MustSignNewTx(acc.key, signer, &types.LegacyTx{
+			Nonce:    uint64(i),
+			GasPrice: b.BaseFee(),
+			Gas:      params.TxGas,
+			To:       &recipient,
+			Value:    big.NewInt(500),
+		})
+		b.AddTx(tx)
+	})
+
+	ctx := context.Background()
+	stateDB, baseHeader, err := backend.StateAndHeaderByNumberOrHash(ctx, rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber))
+	if err != nil {
+		t.Fatalf("failed to get state and header: %v", err)
+	}
+
+	sim := &simulator{
+		b:              backend,
+		state:          stateDB,
+		base:           baseHeader,
+		chainConfig:    backend.ChainConfig(),
+		gp:             new(core.GasPool).AddGas(math.MaxUint64),
+		traceTransfers: false,
+		validate:       false,
+		fullTx:         false,
+	}
+
+	var (
+		call1 = TransactionArgs{
+			From:  &sender,
+			To:    &recipient,
+			Value: (*hexutil.Big)(big.NewInt(1000)),
+		}
+		call2 = TransactionArgs{
+			From:  &sender,
+			To:    &recipient,
+			Value: (*hexutil.Big)(big.NewInt(2000)),
+		}
+		call3a = TransactionArgs{
+			From:  &sender,
+			To:    &contractAddr,
+			Input: uint256ToBytes(uint256.NewInt(baseHeader.Number.Uint64() + 1)),
+			Gas:   newUint64(1000000),
+		}
+		call3b = TransactionArgs{
+			From:  &sender,
+			To:    &contractAddr,
+			Input: uint256ToBytes(uint256.NewInt(baseHeader.Number.Uint64() + 2)),
+			Gas:   newUint64(1000000),
+		}
+		blocks = []simBlock{
+			{Calls: []TransactionArgs{call1}},
+			{Calls: []TransactionArgs{call2}},
+			{Calls: []TransactionArgs{call3a, call3b}},
+		}
+	)
+
+	results, err := sim.execute(ctx, blocks)
+	if err != nil {
+		t.Fatalf("simulation execution failed: %v", err)
+	}
+	require.Equal(t, 3, len(results), "expected 3 simulated blocks")
+
+	// Check linkages of simulated blocks:
+	// Verify that block2's parent hash equals block1's hash.
+	block1 := results[0].Block
+	block2 := results[1].Block
+	block3 := results[2].Block
+	require.Equal(t, block1.ParentHash(), baseHeader.Hash(), "parent hash of block1 should equal hash of base block")
+	require.Equal(t, block1.Hash(), block2.Header().ParentHash, "parent hash of block2 should equal hash of block1")
+	require.Equal(t, block2.Hash(), block3.Header().ParentHash, "parent hash of block3 should equal hash of block2")
+
+	// In block3, two calls were executed to our contract.
+	// The first call in block3 should return the blockhash for block1 (i.e. block1.Hash()),
+	// whereas the second call should return the blockhash for block2 (i.e. block2.Hash()).
+	require.Equal(t, block1.Hash().Bytes(), []byte(results[2].Calls[0].ReturnValue), "returned blockhash for block1 does not match")
+	require.Equal(t, block2.Hash().Bytes(), []byte(results[2].Calls[1].ReturnValue), "returned blockhash for block2 does not match")
+}
+
 func TestSignTransaction(t *testing.T) {
 	t.Parallel()
 	// Initialize test accounts

internal/ethapi/simulate.go

@@ -73,6 +73,20 @@ func (r *simCallResult) MarshalJSON() ([]byte, error) {
 	return json.Marshal((*callResultAlias)(r))
 }
 
+// simBlockResult is the result of a simulated block.
+type simBlockResult struct {
+	fullTx      bool
+	chainConfig *params.ChainConfig
+	Block       *types.Block
+	Calls       []simCallResult
+}
+
+func (r *simBlockResult) MarshalJSON() ([]byte, error) {
+	blockData := RPCMarshalBlock(r.Block, true, r.fullTx, r.chainConfig)
+	blockData["calls"] = r.Calls
+	return json.Marshal(blockData)
+}
+
 // simOpts are the inputs to eth_simulateV1.
 type simOpts struct {
 	BlockStateCalls        []simBlock
@@ -95,7 +109,7 @@ type simulator struct {
 }
 
 // execute runs the simulation of a series of blocks.
-func (sim *simulator) execute(ctx context.Context, blocks []simBlock) ([]map[string]interface{}, error) {
+func (sim *simulator) execute(ctx context.Context, blocks []simBlock) ([]*simBlockResult, error) {
 	if err := ctx.Err(); err != nil {
 		return nil, err
 	}
@@ -123,19 +137,21 @@ func (sim *simulator) execute(ctx context.Context, blocks []simBlock) ([]map[str
 		return nil, err
 	}
 	var (
-		results = make([]map[string]interface{}, len(blocks))
-		parent  = sim.base
+		results = make([]*simBlockResult, len(blocks))
+		// prevHeaders is the header for all previously simulated blocks.
+		// It is "filled" compared to the barebone header available prior to execution.
+		// It will be used for serving the BLOCKHASH opcode.
+		prevHeaders = make([]*types.Header, 0, len(blocks))
+		parent      = sim.base
 	)
 	for bi, block := range blocks {
-		result, callResults, err := sim.processBlock(ctx, &block, headers[bi], parent, headers[:bi], timeout)
+		result, callResults, err := sim.processBlock(ctx, &block, headers[bi], parent, prevHeaders, timeout)
 		if err != nil {
 			return nil, err
 		}
-		enc := RPCMarshalBlock(result, true, sim.fullTx, sim.chainConfig)
-		enc["calls"] = callResults
-		results[bi] = enc
-
-		parent = headers[bi]
+		results[bi] = &simBlockResult{fullTx: sim.fullTx, chainConfig: sim.chainConfig, Block: result, Calls: callResults}
+		parent = result.Header()
+		prevHeaders = append(prevHeaders, parent)
 	}
 	return results, nil
 }