error migration (#254)

* migrate errors

* ante handler errors

* return err instead of panic

x/evm/types/codec.go

@@ -4,18 +4,19 @@ import (
 	"github.com/cosmos/cosmos-sdk/codec"
 )
 
-// ModuleCdc defines the codec to be used by evm module
+// ModuleCdc defines the evm module's codec
 var ModuleCdc = codec.New()
 
-func init() {
-	cdc := codec.New()
-	codec.RegisterCrypto(cdc)
-	ModuleCdc = cdc.Seal()
-}
-
-// RegisterCodec registers concrete types and interfaces on the given codec.
+// RegisterCodec registers all the necessary types and interfaces for the
+// evm module
 func RegisterCodec(cdc *codec.Codec) {
 	cdc.RegisterConcrete(MsgEthereumTx{}, "ethermint/MsgEthereumTx", nil)
 	cdc.RegisterConcrete(MsgEthermint{}, "ethermint/MsgEthermint", nil)
 	cdc.RegisterConcrete(EncodableTxData{}, "ethermint/EncodableTxData", nil)
 }
+
+func init() {
+	RegisterCodec(ModuleCdc)
+	codec.RegisterCrypto(ModuleCdc)
+	ModuleCdc.Seal()
+}

x/evm/types/emint_msg.go

@@ -1,9 +1,8 @@
 package types
 
 import (
-	"fmt"
-
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 
 	"github.com/cosmos/ethermint/types"
 	ethcmn "github.com/ethereum/go-ethereum/common"
@@ -61,12 +60,16 @@ func (msg MsgEthermint) GetSignBytes() []byte {
 // ValidateBasic runs stateless checks on the message
 func (msg MsgEthermint) ValidateBasic() sdk.Error {
 	if msg.Price.Sign() != 1 {
-		return types.ErrInvalidValue(fmt.Sprintf("Price must be positive: %x", msg.Price))
+		return sdk.ConvertError(
+			sdkerrors.Wrapf(types.ErrInvalidValue, "price must be positive %s", msg.Price),
+		)
 	}
 
 	// Amount can be 0
 	if msg.Amount.Sign() == -1 {
-		return types.ErrInvalidValue(fmt.Sprintf("amount cannot be negative: %x", msg.Amount))
+		return sdk.ConvertError(
+			sdkerrors.Wrapf(types.ErrInvalidValue, "amount cannot be negative %s", msg.Amount),
+		)
 	}
 
 	return nil

x/evm/types/msg.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	"github.com/cosmos/ethermint/types"
 
 	ethcmn "github.com/ethereum/go-ethereum/common"
@@ -127,12 +128,16 @@ func (msg MsgEthereumTx) Type() string { return TypeMsgEthereumTx }
 // checks of a Transaction. If returns an error if validation fails.
 func (msg MsgEthereumTx) ValidateBasic() sdk.Error {
 	if msg.Data.Price.Sign() != 1 {
-		return types.ErrInvalidValue(fmt.Sprintf("price must be positive: %x", msg.Data.Price))
+		return sdk.ConvertError(
+			sdkerrors.Wrapf(types.ErrInvalidValue, "price must be positive %s", msg.Data.Price),
+		)
 	}
 
 	// Amount can be 0
 	if msg.Data.Amount.Sign() == -1 {
-		return types.ErrInvalidValue(fmt.Sprintf("amount must be positive: %x", msg.Data.Amount))
+		return sdk.ConvertError(
+			sdkerrors.Wrapf(types.ErrInvalidValue, "amount cannot be negative %s", msg.Data.Amount),
+		)
 	}
 
 	return nil
@@ -306,12 +311,18 @@ func TxDecoder(cdc *codec.Codec) sdk.TxDecoder {
 		var tx sdk.Tx
 
 		if len(txBytes) == 0 {
-			return nil, sdk.ErrTxDecode("txBytes are empty")
+			return nil, sdk.ConvertError(
+				sdkerrors.Wrap(sdkerrors.ErrTxDecode, "tx bytes are empty"),
+			)
 		}
 
+		// sdk.Tx is an interface. The concrete message types
+		// are registered by MakeTxCodec
 		err := cdc.UnmarshalBinaryLengthPrefixed(txBytes, &tx)
 		if err != nil {
-			return nil, sdk.ErrTxDecode("failed to decode tx").TraceSDK(err.Error())
+			return nil, sdk.ConvertError(
+				sdkerrors.Wrap(sdkerrors.ErrTxDecode, err.Error()),
+			)
 		}
 
 		return tx, nil

x/evm/types/state_transition.go

@@ -1,7 +1,7 @@
 package types
 
 import (
-	"fmt"
+	"errors"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	emint "github.com/cosmos/ethermint/types"
 )
 
@@ -39,12 +40,11 @@ type ReturnData struct {
 // TransitionCSDB performs an evm state transition from a transaction
 // TODO: update godoc, it doesn't explain what it does in depth.
 func (st StateTransition) TransitionCSDB(ctx sdk.Context) (*ReturnData, error) {
-	returnData := new(ReturnData)
 	contractCreation := st.Recipient == nil
 
 	cost, err := core.IntrinsicGas(st.Payload, contractCreation, true)
 	if err != nil {
-		return nil, fmt.Errorf("invalid intrinsic gas for transaction: %s", err.Error())
+		return nil, sdkerrors.Wrap(err, "invalid intrinsic gas for transaction")
 	}
 
 	// This gas limit the the transaction gas limit with intrinsic gas subtracted
@@ -73,6 +73,11 @@ func (st StateTransition) TransitionCSDB(ctx sdk.Context) (*ReturnData, error) {
 	// Clear cache of accounts to handle changes outside of the EVM
 	csdb.UpdateAccounts()
 
+	gasPrice := ctx.MinGasPrices().AmountOf(emint.DenomDefault)
+	if gasPrice.IsNil() {
+		return nil, errors.New("gas price cannot be nil")
+	}
+
 	// Create context for evm
 	context := vm.Context{
 		CanTransfer: core.CanTransfer,
@@ -83,7 +88,7 @@ func (st StateTransition) TransitionCSDB(ctx sdk.Context) (*ReturnData, error) {
 		Time:        big.NewInt(ctx.BlockHeader().Time.Unix()),
 		Difficulty:  big.NewInt(0), // unused. Only required in PoW context
 		GasLimit:    gasLimit,
-		GasPrice:    ctx.MinGasPrices().AmountOf(emint.DenomDefault).Int,
+		GasPrice:    gasPrice.Int,
 	}
 
 	evm := vm.NewEVM(context, csdb, GenerateChainConfig(st.ChainID), vm.Config{})
@@ -150,7 +155,7 @@ func (st StateTransition) TransitionCSDB(ctx sdk.Context) (*ReturnData, error) {
 	// handle errors
 	if err != nil {
 		if err == vm.ErrOutOfGas || err == vm.ErrCodeStoreOutOfGas {
-			return nil, fmt.Errorf("evm execution went out of gas: %s", err.Error())
+			return nil, sdkerrors.Wrap(err, "evm execution went out of gas")
 		}
 
 		// Consume gas before returning
@@ -177,8 +182,11 @@ func (st StateTransition) TransitionCSDB(ctx sdk.Context) (*ReturnData, error) {
 		return nil, err
 	}
 
-	returnData.Logs = logs
-	returnData.Bloom = bloomInt
-	returnData.Result = &sdk.Result{Data: resultData, GasUsed: gasConsumed}
+	returnData := &ReturnData{
+		Logs:   logs,
+		Bloom:  bloomInt,
+		Result: &sdk.Result{Data: resultData},
+	}
+
 	return returnData, nil
 }

x/evm/types/statedb.go

@@ -165,6 +165,10 @@ func (csdb *CommitStateDB) SetLogs(hash ethcmn.Hash, logs []*ethtypes.Log) error
 		return err
 	}
 
+	if len(enc) == 0 {
+		return nil
+	}
+
 	store.Set(LogsKey(hash[:]), enc)
 	return nil
 }
@@ -310,18 +314,14 @@ func (csdb *CommitStateDB) GetLogs(hash ethcmn.Hash) ([]*ethtypes.Log, error) {
 
 	encLogs := store.Get(LogsKey(hash[:]))
 	if len(encLogs) == 0 {
+		// return nil if logs are not found
 		return []*ethtypes.Log{}, nil
 	}
 
-	logs, err := DecodeLogs(encLogs)
-	if err != nil {
-		return nil, err
-	}
-
-	return logs, nil
+	return DecodeLogs(encLogs)
 }
 
-// Logs returns all the current logs in the state.
+// AllLogs returns all the current logs in the state.
 func (csdb *CommitStateDB) AllLogs() []*ethtypes.Log {
 	// nolint: prealloc
 	var logs []*ethtypes.Log