ante, evm: fix panic when checking BlockGasMeter (#120)

* ante, evm: fix panic when checking BlockGasMeter

* update block gas limit function

app/ante/eth.go

@@ -7,6 +7,7 @@ import (
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	authante "github.com/cosmos/cosmos-sdk/x/auth/ante"
 
+	ethermint "github.com/cosmos/ethermint/types"
 	evmtypes "github.com/cosmos/ethermint/x/evm/types"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -296,10 +297,16 @@ func (egcd EthGasConsumeDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simula
 		ctx.GasMeter().ConsumeGas(intrinsicGas, "intrinsic gas")
 	}
 
-	// generate a copy of the gas pool (i.e block gas meter) to see if we've run out of gas for this block
-	// if current gas consumed is greater than the limit, this funcion panics and the error is recovered on the Baseapp
-	gasPool := sdk.NewGasMeter(ctx.BlockGasMeter().Limit())
-	gasPool.ConsumeGas(ctx.GasMeter().GasConsumedToLimit(), "gas pool check")
+	// TODO: deprecate after https://github.com/cosmos/cosmos-sdk/issues/9514  is fixed on SDK
+	blockGasLimit := ethermint.BlockGasLimit(ctx)
+
+	// NOTE: safety check
+	if blockGasLimit > 0 {
+		// generate a copy of the gas pool (i.e block gas meter) to see if we've run out of gas for this block
+		// if current gas consumed is greater than the limit, this funcion panics and the error is recovered on the Baseapp
+		gasPool := sdk.NewGasMeter(blockGasLimit)
+		gasPool.ConsumeGas(ctx.GasMeter().GasConsumedToLimit(), "gas pool check")
+	}
 
 	// we know that we have enough gas on the pool to cover the intrinsic gas
 	// set up the updated context to the evm Keeper

ethereum/rpc/eth_api.go

@@ -96,7 +96,7 @@ func (e *PublicEthAPI) ClientCtx() client.Context {
 // ProtocolVersion returns the supported Ethereum protocol version.
 func (e *PublicEthAPI) ProtocolVersion() hexutil.Uint {
 	e.logger.Debugln("eth_protocolVersion")
-	return hexutil.Uint(evmtypes.ProtocolVersion)
+	return hexutil.Uint(ethermint.ProtocolVersion)
 }
 
 // ChainId returns the chain's identifier in hex format

tests/rpc/rpc_test.go

@@ -20,7 +20,9 @@ import (
 	"github.com/stretchr/testify/require"
 
 	rpctypes "github.com/cosmos/ethermint/ethereum/rpc/types"
+	ethermint "github.com/cosmos/ethermint/types"
 	evmtypes "github.com/cosmos/ethermint/x/evm/types"
+
 	ethcmn "github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	ethtypes "github.com/ethereum/go-ethereum/core/types"
@@ -230,7 +232,7 @@ func TestEth_GetTransactionLogs(t *testing.T) {
 }
 
 func TestEth_protocolVersion(t *testing.T) {
-	expectedRes := hexutil.Uint(evmtypes.ProtocolVersion)
+	expectedRes := hexutil.Uint(ethermint.ProtocolVersion)
 
 	rpcRes := call(t, "eth_protocolVersion", []string{})
 

types/block.go

@@ -0,0 +1,25 @@
+package types
+
+import sdk "github.com/cosmos/cosmos-sdk/types"
+
+// BlockGasLimit returns the max gas (limit) defined in the block gas meter. If the meter is not
+// set, it returns the max gas from the application consensus params.
+// NOTE: see https://github.com/cosmos/cosmos-sdk/issues/9514 for full reference
+func BlockGasLimit(ctx sdk.Context) uint64 {
+	blockGasMeter := ctx.BlockGasMeter()
+	if blockGasMeter != nil {
+		return blockGasMeter.Limit()
+	}
+
+	cp := ctx.ConsensusParams()
+	if cp == nil || cp.Block == nil {
+		return 0
+	}
+
+	maxGas := cp.Block.MaxGas
+	if maxGas > 0 {
+		return uint64(maxGas)
+	}
+
+	return 0
+}

x/evm/keeper/state_transition.go

@@ -14,6 +14,7 @@ import (
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 
+	ethermint "github.com/cosmos/ethermint/types"
 	"github.com/cosmos/ethermint/x/evm/types"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -30,7 +31,7 @@ func (k *Keeper) NewEVM(msg core.Message, config *params.ChainConfig) *vm.EVM {
 		Transfer:    core.Transfer,
 		GetHash:     k.GetHashFn(),
 		Coinbase:    common.Address{}, // there's no beneficiary since we're not mining
-		GasLimit:    k.ctx.BlockGasMeter().Limit(),
+		GasLimit:    ethermint.BlockGasLimit(k.ctx),
 		BlockNumber: big.NewInt(k.ctx.BlockHeight()),
 		Time:        big.NewInt(k.ctx.BlockHeader().Time.Unix()),
 		Difficulty:  big.NewInt(0), // unused. Only required in PoW context

x/evm/types/protocol.go

@@ -1,9 +0,0 @@
-package types
-
-// Constants to match up protocol versions and messages
-const (
-	eth65 = 65
-
-	// ProtocolVersion is the latest supported version of the eth protocol.
-	ProtocolVersion = eth65
-)