feat: add convert coin endpoint

proto/cosmos/evm/erc20/v1/tx.proto

@@ -4,11 +4,11 @@ package cosmos.evm.erc20.v1;
 
 import "amino/amino.proto";
 import "cosmos/base/v1beta1/coin.proto";
+import "cosmos/evm/erc20/v1/genesis.proto";
 import "cosmos/msg/v1/msg.proto";
 import "cosmos_proto/cosmos.proto";
 import "gogoproto/gogo.proto";
 import "google/api/annotations.proto";
-import "cosmos/evm/erc20/v1/genesis.proto";
 
 option go_package = "github.com/cosmos/evm/x/erc20/types";
 
@@ -20,6 +20,11 @@ service Msg {
   rpc ConvertERC20(MsgConvertERC20) returns (MsgConvertERC20Response) {
     option (google.api.http).get = "/cosmos/evm/erc20/v1/tx/convert_erc20";
   };
+  // ConvertCoin mints a ERC20 token representation of the native Cosmos coin
+  // that is registered on the token mapping.
+  rpc ConvertCoin(MsgConvertCoin) returns (MsgConvertCoinResponse) {
+    option (google.api.http).get = "/cosmos/evm/erc20/v1/tx/convert_coin";
+  }
   // UpdateParams defines a governance operation for updating the x/erc20 module
   // parameters. The authority is hard-coded to the Cosmos SDK x/gov module
   // account
@@ -60,6 +65,8 @@ message MsgConvertERC20Response {}
 
 // MsgConvertCoin defines a Msg to convert a native Cosmos coin to a ERC20 token
 message MsgConvertCoin {
+  option (amino.name) = "cosmos/evm/x/erc20/MsgConvertCoin";
+  option (cosmos.msg.v1.signer) = "sender";
   // coin is a Cosmos coin whose denomination is registered in a token pair. The
   // coin amount defines the amount of coins to convert.
   cosmos.base.v1beta1.Coin coin = 1 [ (gogoproto.nullable) = false ];

x/erc20/client/cli/tx.go

@@ -28,6 +28,7 @@ func NewTxCmd() *cobra.Command {
 	}
 
 	txCmd.AddCommand(
+		NewConvertCoinCmd(),
 		NewConvertERC20Cmd(),
 	)
 	return txCmd
@@ -79,3 +80,50 @@ func NewConvertERC20Cmd() *cobra.Command {
 	flags.AddTxFlagsToCmd(cmd)
 	return cmd
 }
+
+// NewConvertCoinCmd returns a CLI command handler for converting a Cosmos coin
+func NewConvertCoinCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "convert-coin COIN [RECEIVER_HEX]",
+		Short: "Convert a Cosmos coin to ERC20. When the receiver [optional] is omitted, the ERC20 tokens are transferred to the sender.",
+		Args:  cobra.RangeArgs(1, 2),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cliCtx, err := client.GetClientTxContext(cmd)
+			if err != nil {
+				return err
+			}
+
+			coin, err := sdk.ParseCoinNormalized(args[0])
+			if err != nil {
+				return err
+			}
+
+			var receiver string
+			sender := cliCtx.GetFromAddress()
+
+			if len(args) == 2 {
+				receiver = args[1]
+				if err := cosmosevmtypes.ValidateAddress(receiver); err != nil {
+					return fmt.Errorf("invalid receiver hex address %w", err)
+				}
+			} else {
+				receiver = common.BytesToAddress(sender).Hex()
+			}
+
+			msg := &types.MsgConvertCoin{
+				Coin:     coin,
+				Receiver: receiver,
+				Sender:   sender.String(),
+			}
+
+			if err := msg.ValidateBasic(); err != nil {
+				return err
+			}
+
+			return tx.GenerateOrBroadcastTxCLI(cliCtx, cmd.Flags(), msg)
+		},
+	}
+
+	flags.AddTxFlagsToCmd(cmd)
+	return cmd
+}

x/erc20/keeper/msg_server.go

@@ -186,6 +186,46 @@ func (k Keeper) convertERC20IntoCoinsForNativeToken(
 	return &types.MsgConvertERC20Response{}, nil
 }
 
+// ConvertCoin converts native Cosmos coins into ERC20 tokens for both
+// Cosmos-native and ERC20 TokenPair Owners
+func (k Keeper) ConvertCoin(
+	goCtx context.Context,
+	msg *types.MsgConvertCoin,
+) (*types.MsgConvertCoinResponse, error) {
+	ctx := sdk.UnwrapSDKContext(goCtx)
+
+	// Error checked during msg validation
+	sender := sdk.MustAccAddressFromBech32(msg.Sender)
+	receiver := common.HexToAddress(msg.Receiver)
+
+	pair, err := k.MintingEnabled(ctx, sender, receiver.Bytes(), msg.Coin.Denom)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check ownership and execute conversion
+	switch {
+	case pair.IsNativeERC20():
+		// Remove token pair if contract is suicided
+		acc := k.evmKeeper.GetAccountWithoutBalance(ctx, pair.GetERC20Contract())
+		if acc == nil || !acc.IsContract() {
+			k.DeleteTokenPair(ctx, pair)
+			k.Logger(ctx).Debug(
+				"deleting selfdestructed token pair from state",
+				"contract", pair.Erc20Address,
+			)
+			// NOTE: return nil error to persist the changes from the deletion
+			return nil, nil
+		}
+
+		return nil, k.ConvertCoinNativeERC20(ctx, pair, msg.Coin.Amount, receiver, sender)
+	case pair.IsNativeCoin():
+		return nil, types.ErrNativeConversionDisabled
+	}
+
+	return nil, types.ErrUndefinedOwner
+}
+
 // ConvertCoinNativeERC20 handles the coin conversion for a native ERC20 token
 // pair:
 //   - escrow Coins on module account
@@ -201,7 +241,7 @@ func (k Keeper) ConvertCoinNativeERC20(
 	sender sdk.AccAddress,
 ) error {
 	if !amount.IsPositive() {
-		return nil
+		return sdkerrors.Wrap(types.ErrNegativeToken, "converted coin amount must be positive")
 	}
 
 	erc20 := contracts.ERC20MinterBurnerDecimalsContract.ABI