feat: Tac simulate rpc

proto/cosmos/evm/vm/v1/query.proto

@@ -59,6 +59,11 @@ service Query {
     option (google.api.http).get = "/cosmos/evm/vm/v1/eth_call";
   }
 
+  // TacSimulate implements the custom `tac_simulate` rpc api which supports state override
+  rpc TacSimulate(TacSimulateRequest) returns (TacSimulateResponse) {
+    option (google.api.http).get = "/cosmos/evm/vm/v1/tac_simulate";
+  }
+
   // EstimateGas implements the `eth_estimateGas` rpc api
   rpc EstimateGas(EthCallRequest) returns (EstimateGasResponse) {
     option (google.api.http).get = "/cosmos/evm/vm/v1/estimate_gas";
@@ -260,6 +265,40 @@ message EthCallRequest {
   int64 chain_id = 4;
 }
 
+// TacSimulateRequest defines TacSimulate request
+message TacSimulateRequest {
+  // args uses the same json format as the json rpc api.
+  bytes args = 1;
+  // state_override defines the state override for the call, it uses the same json format as the json rpc api.
+  bytes state_override = 2;
+  // gas_cap defines the default gas cap to be used
+  uint64 gas_cap = 3;
+  // proposer_address of the requested block in hex format
+  bytes proposer_address = 4
+      [ (gogoproto.casttype) =
+            "github.com/cosmos/cosmos-sdk/types.ConsAddress" ];
+  // chain_id is the eip155 chain id parsed from the requested block header
+  int64 chain_id = 5;
+}
+
+// TacSimulateResponse defines TacSimulate response
+message TacSimulateResponse {
+  // hash of the ethereum transaction in hex format
+  string hash = 1;
+  // logs contains the proto-compatible ethereum logs
+  repeated Log logs = 2;
+  // ret is the returned data from evm function (result or data supplied with
+  // revert opcode)
+  bytes ret = 3;
+  // vm_error is the error returned by vm execution
+  string vm_error = 4;
+  // gas_used specifies how much gas was consumed by the EVM execution
+  uint64 gas_used = 5;
+  // gas_estimated is the estimated minimum gas limit needed to execute
+  // the transaction successfully (result of binary search, like eth_estimateGas)
+  uint64 gas_estimated = 6;
+}
+
 // EstimateGasResponse defines EstimateGas response
 message EstimateGasResponse {
   // gas returns the estimated gas

rpc/apis.go

@@ -14,6 +14,7 @@ import (
 	"github.com/cosmos/evm/rpc/namespaces/ethereum/miner"
 	"github.com/cosmos/evm/rpc/namespaces/ethereum/net"
 	"github.com/cosmos/evm/rpc/namespaces/ethereum/personal"
+	"github.com/cosmos/evm/rpc/namespaces/ethereum/tac"
 	"github.com/cosmos/evm/rpc/namespaces/ethereum/txpool"
 	"github.com/cosmos/evm/rpc/namespaces/ethereum/web3"
 	"github.com/cosmos/evm/types"
@@ -37,6 +38,7 @@ const (
 	TxPoolNamespace   = "txpool"
 	DebugNamespace    = "debug"
 	MinerNamespace    = "miner"
+	TacNamespace      = "tac"
 
 	apiVersion = "1.0"
 )
@@ -155,6 +157,22 @@ func init() {
 				},
 			}
 		},
+		TacNamespace: func(ctx *server.Context,
+			clientCtx client.Context,
+			_ *rpcclient.WSClient,
+			allowUnprotectedTxs bool,
+			indexer types.EVMTxIndexer,
+		) []rpc.API {
+			evmBackend := backend.NewBackend(ctx, ctx.Logger, clientCtx, allowUnprotectedTxs, indexer)
+			return []rpc.API{
+				{
+					Namespace: TacNamespace,
+					Version:   apiVersion,
+					Service:   tac.NewTacAPI(ctx.Logger, evmBackend),
+					Public:    true,
+				},
+			}
+		},
 	}
 }
 

rpc/backend/backend.go

@@ -110,6 +110,7 @@ type EVMBackend interface {
 	SetTxDefaults(args evmtypes.TransactionArgs) (evmtypes.TransactionArgs, error)
 	EstimateGas(args evmtypes.TransactionArgs, blockNrOptional *rpctypes.BlockNumber) (hexutil.Uint64, error)
 	DoCall(args evmtypes.TransactionArgs, blockNr rpctypes.BlockNumber) (*evmtypes.MsgEthereumTxResponse, error)
+	DoTacSimulate(args evmtypes.TransactionArgs, blockNr rpctypes.BlockNumber, stateOverride evmtypes.StateOverride) (*evmtypes.TacSimulateResponse, error)
 	GasPrice() (*hexutil.Big, error)
 
 	// Filter API

rpc/backend/call_tx.go

@@ -372,6 +372,66 @@ func (b *Backend) DoCall(
 	return res, nil
 }
 
+func (b *Backend) DoTacSimulate(
+	args evmtypes.TransactionArgs,
+	blockNr rpctypes.BlockNumber,
+	stateOverride evmtypes.StateOverride,
+) (*evmtypes.TacSimulateResponse, error) {
+	bz, err := json.Marshal(&args)
+	if err != nil {
+		return nil, err
+	}
+
+	header, err := b.TendermintBlockByNumber(blockNr)
+	if err != nil {
+		// the error message imitates geth behavior
+		return nil, errors.New("header not found")
+	}
+
+	overrideBz, err := json.Marshal(stateOverride)
+	if err != nil {
+		return nil, err
+	}
+
+	req := evmtypes.TacSimulateRequest{
+		Args:            bz,
+		GasCap:          b.RPCGasCap(),
+		ProposerAddress: sdk.ConsAddress(header.Block.ProposerAddress),
+		ChainId:         b.chainID.Int64(),
+		StateOverride:   overrideBz,
+	}
+
+	// From ContextWithHeight: if the provided height is 0,
+	// it will return an empty context and the gRPC query will use
+	// the latest block height for querying.
+	ctx := rpctypes.ContextWithHeight(blockNr.Int64())
+	timeout := b.RPCEVMTimeout()
+
+	// Setup context so it may be canceled the call has completed
+	// or, in case of unmetered gas, setup a context with a timeout.
+	var cancel context.CancelFunc
+	if timeout > 0 {
+		ctx, cancel = context.WithTimeout(ctx, timeout)
+	} else {
+		ctx, cancel = context.WithCancel(ctx)
+	}
+
+	// Make sure the context is canceled when the call has completed
+	// this makes sure resources are cleaned up.
+	defer cancel()
+
+	res, err := b.queryClient.TacSimulate(ctx, &req)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = handleRevertError(res.VmError, res.Ret); err != nil {
+		return nil, err
+	}
+
+	return res, nil
+}
+
 // GasPrice returns the current gas price based on Cosmos EVM' gas price oracle.
 func (b *Backend) GasPrice() (*hexutil.Big, error) {
 	var (