Custom MsgMultiSend Handler (x/bank fork)

PENDING.md

@@ -19,6 +19,10 @@
 
 ### Gaia
 
+* [\#3787] Fork the `x/bank` module into the Gaia application with only a
+modified message handler, where the modified message handler behaves the same as
+the standard `x/bank` message handler except for `MsgMultiSend` that must burn
+exactly 9 atoms and transfer 1 atom, and `MsgSend` is disabled.
 * [\#3789] Update validator creation flow:
   * Remove `NewMsgCreateValidatorOnBehalfOf` and corresponding business logic
   * Ensure the validator address equals the delegator address during
@@ -32,6 +36,7 @@ tags.
 * [\#3751] Disable (temporarily) support for ED25519 account key pairs.
 
 ### Tendermint
+
 * [\#3804] Update to Tendermint `v0.31.0-dev0`
 
 <!--------------------------------- FEATURES --------------------------------->

cmd/gaia/app/app.go

@@ -11,6 +11,9 @@ import (
 	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
 
+	// TODO: Remove once transfers are enabled.
+	gaiabank "github.com/cosmos/cosmos-sdk/cmd/gaia/app/x/bank"
+
 	bam "github.com/cosmos/cosmos-sdk/baseapp"
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -149,8 +152,10 @@ func NewGaiaApp(logger log.Logger, db dbm.DB, traceStore io.Writer, loadLatest b
 	)
 
 	// register message routes
+	//
+	// TODO: Use standard bank router once transfers are enabled.
 	app.Router().
-		AddRoute(bank.RouterKey, bank.NewHandler(app.bankKeeper)).
+		AddRoute(bank.RouterKey, gaiabank.NewHandler(app.bankKeeper)).
 		AddRoute(staking.RouterKey, staking.NewHandler(app.stakingKeeper)).
 		AddRoute(distr.RouterKey, distr.NewHandler(app.distrKeeper)).
 		AddRoute(slashing.RouterKey, slashing.NewHandler(app.slashingKeeper)).

cmd/gaia/app/genesis.go

@@ -11,13 +11,12 @@ import (
 	"strings"
 	"time"
 
-	"github.com/cosmos/cosmos-sdk/x/bank"
-
 	tmtypes "github.com/tendermint/tendermint/types"
 
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth"
+	"github.com/cosmos/cosmos-sdk/x/bank"
 	distr "github.com/cosmos/cosmos-sdk/x/distribution"
 	"github.com/cosmos/cosmos-sdk/x/gov"
 	"github.com/cosmos/cosmos-sdk/x/mint"

cmd/gaia/app/x/bank/handler.go

@@ -0,0 +1,100 @@
+// Package bank contains a forked version of the bank module. It only contains
+// a modified message handler to support a very limited form of transfers during
+// mainnet launch -- MsgMultiSend messages.
+//
+// NOTE: This fork should be removed entirely once transfers are enabled and
+// the Gaia router should be reset to using the original bank module handler.
+package bank
+
+import (
+	"github.com/tendermint/tendermint/crypto"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/bank"
+)
+
+var (
+	uatomDenom    = "uatom"
+	atomsToUatoms = int64(1000000)
+
+	// BurnedCoinsAccAddr represents the burn account address used for
+	// MsgMultiSend message during the period for which transfers are disabled.
+	// Its Bech32 address is cosmos1x4p90uuy63fqzsheamn48vq88q3eusykf0a69v.
+	BurnedCoinsAccAddr = sdk.AccAddress(crypto.AddressHash([]byte("bankBurnedCoins")))
+)
+
+// NewHandler returns a handler for "bank" type messages.
+func NewHandler(k bank.Keeper) sdk.Handler {
+	return func(ctx sdk.Context, msg sdk.Msg) sdk.Result {
+		switch msg := msg.(type) {
+		case bank.MsgSend:
+			return handleMsgSend(ctx, k, msg)
+
+		case bank.MsgMultiSend:
+			return handleMsgMultiSend(ctx, k, msg)
+
+		default:
+			errMsg := "Unrecognized bank Msg type: %s" + msg.Type()
+			return sdk.ErrUnknownRequest(errMsg).Result()
+		}
+	}
+}
+
+// handleMsgSend implements a MsgSend message handler. It operates no differently
+// than the standard bank module MsgSend message handler in that it transfers
+// an amount from one account to another under the condition of transfers being
+// enabled.
+func handleMsgSend(ctx sdk.Context, k bank.Keeper, msg bank.MsgSend) sdk.Result {
+	// No need to modify handleMsgSend as the forked module requires no changes,
+	// so we can just call the standard bank modules handleMsgSend since we know
+	// the message is of type MsgSend.
+	return bank.NewHandler(k)(ctx, msg)
+}
+
+// handleMsgMultiSend implements a modified forked version of a MsgMultiSend
+// message handler. If transfers are disabled, a modified version of MsgMultiSend
+// is allowed where there must be a single input and only two outputs. The first
+// of the two outputs must be to a specific burn address defined by
+// burnedCoinsAccAddr. In addition, the output amounts must be of 9atom and
+// 1uatom respectively.
+func handleMsgMultiSend(ctx sdk.Context, k bank.Keeper, msg bank.MsgMultiSend) sdk.Result {
+	// NOTE: totalIn == totalOut should already have been checked
+	if !k.GetSendEnabled(ctx) {
+		if !validateMultiSendTransfersDisabled(msg) {
+			return bank.ErrSendDisabled(k.Codespace()).Result()
+		}
+	}
+
+	tags, err := k.InputOutputCoins(ctx, msg.Inputs, msg.Outputs)
+	if err != nil {
+		return err.Result()
+	}
+
+	return sdk.Result{
+		Tags: tags,
+	}
+}
+
+func validateMultiSendTransfersDisabled(msg bank.MsgMultiSend) bool {
+	nineAtoms := sdk.Coins{sdk.NewInt64Coin(uatomDenom, 9*atomsToUatoms)}
+	oneAtom := sdk.Coins{sdk.NewInt64Coin(uatomDenom, 1*atomsToUatoms)}
+
+	if len(msg.Inputs) != 1 {
+		return false
+	}
+	if len(msg.Outputs) != 2 {
+		return false
+	}
+
+	if !msg.Outputs[0].Address.Equals(BurnedCoinsAccAddr) {
+		return false
+	}
+	if !msg.Outputs[0].Coins.IsEqual(nineAtoms) {
+		return false
+	}
+	if !msg.Outputs[1].Coins.IsEqual(oneAtom) {
+		return false
+	}
+
+	return true
+}

cmd/gaia/app/x/bank/handler_test.go

@@ -0,0 +1,216 @@
+package bank
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	abci "github.com/tendermint/tendermint/abci/types"
+	"github.com/tendermint/tendermint/crypto/secp256k1"
+	dbm "github.com/tendermint/tendermint/libs/db"
+	"github.com/tendermint/tendermint/libs/log"
+
+	"github.com/cosmos/cosmos-sdk/codec"
+	"github.com/cosmos/cosmos-sdk/store"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/auth"
+	"github.com/cosmos/cosmos-sdk/x/bank"
+	"github.com/cosmos/cosmos-sdk/x/params"
+)
+
+var (
+	addrs = []sdk.AccAddress{
+		sdk.AccAddress(secp256k1.GenPrivKey().PubKey().Address()),
+		sdk.AccAddress(secp256k1.GenPrivKey().PubKey().Address()),
+		sdk.AccAddress(secp256k1.GenPrivKey().PubKey().Address()),
+	}
+
+	initAmt = sdk.NewInt(atomsToUatoms * 100)
+)
+
+type testInput struct {
+	ctx        sdk.Context
+	accKeeper  auth.AccountKeeper
+	bankKeeper bank.Keeper
+}
+
+func newTestCodec() *codec.Codec {
+	cdc := codec.New()
+
+	bank.RegisterCodec(cdc)
+	auth.RegisterCodec(cdc)
+	sdk.RegisterCodec(cdc)
+	codec.RegisterCrypto(cdc)
+
+	return cdc
+}
+
+func createTestInput(t *testing.T) testInput {
+	keyAcc := sdk.NewKVStoreKey(auth.StoreKey)
+	keyParams := sdk.NewKVStoreKey(params.StoreKey)
+	tKeyParams := sdk.NewTransientStoreKey(params.TStoreKey)
+
+	cdc := newTestCodec()
+	db := dbm.NewMemDB()
+	ms := store.NewCommitMultiStore(db)
+	ctx := sdk.NewContext(ms, abci.Header{Time: time.Now().UTC()}, false, log.NewNopLogger())
+
+	ms.MountStoreWithDB(keyAcc, sdk.StoreTypeIAVL, db)
+	ms.MountStoreWithDB(tKeyParams, sdk.StoreTypeTransient, db)
+	ms.MountStoreWithDB(keyParams, sdk.StoreTypeIAVL, db)
+
+	require.NoError(t, ms.LoadLatestVersion())
+
+	paramsKeeper := params.NewKeeper(cdc, keyParams, tKeyParams)
+	accKeeper := auth.NewAccountKeeper(
+		cdc,
+		keyAcc,
+		paramsKeeper.Subspace(auth.DefaultParamspace),
+		auth.ProtoBaseAccount,
+	)
+
+	bankKeeper := bank.NewBaseKeeper(
+		accKeeper,
+		paramsKeeper.Subspace(bank.DefaultParamspace),
+		bank.DefaultCodespace,
+	)
+
+	for _, addr := range addrs {
+		_, _, err := bankKeeper.AddCoins(ctx, addr, sdk.Coins{sdk.NewCoin(uatomDenom, initAmt)})
+		require.NoError(t, err)
+	}
+
+	return testInput{ctx, accKeeper, bankKeeper}
+}
+
+func TestHandlerMsgSendTransfersDisabled(t *testing.T) {
+	input := createTestInput(t)
+	input.bankKeeper.SetSendEnabled(input.ctx, false)
+
+	handler := NewHandler(input.bankKeeper)
+	amt := sdk.NewInt(atomsToUatoms * 5)
+	msg := bank.NewMsgSend(addrs[0], addrs[1], sdk.Coins{sdk.NewCoin(uatomDenom, amt)})
+
+	res := handler(input.ctx, msg)
+	require.False(t, res.IsOK(), "expected failed message execution: %v", res.Log)
+
+	from := input.accKeeper.GetAccount(input.ctx, addrs[0])
+	require.Equal(t, from.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, initAmt)})
+
+	to := input.accKeeper.GetAccount(input.ctx, addrs[1])
+	require.Equal(t, to.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, initAmt)})
+}
+
+func TestHandlerMsgSendTransfersEnabled(t *testing.T) {
+	input := createTestInput(t)
+	input.bankKeeper.SetSendEnabled(input.ctx, true)
+
+	handler := NewHandler(input.bankKeeper)
+	amt := sdk.NewInt(atomsToUatoms * 5)
+	msg := bank.NewMsgSend(addrs[0], addrs[1], sdk.Coins{sdk.NewCoin(uatomDenom, amt)})
+
+	res := handler(input.ctx, msg)
+	require.True(t, res.IsOK(), "expected successful message execution: %v", res.Log)
+
+	from := input.accKeeper.GetAccount(input.ctx, addrs[0])
+	balance := initAmt.Sub(amt)
+	require.Equal(t, from.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+
+	to := input.accKeeper.GetAccount(input.ctx, addrs[1])
+	balance = initAmt.Add(amt)
+	require.Equal(t, to.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+}
+
+func TestHandlerMsgMultiSendTransfersDisabledBurn(t *testing.T) {
+	input := createTestInput(t)
+	input.bankKeeper.SetSendEnabled(input.ctx, false)
+
+	handler := NewHandler(input.bankKeeper)
+	totalAmt := sdk.NewInt(10 * atomsToUatoms)
+	burnAmt := sdk.NewInt(9 * atomsToUatoms)
+	transAmt := sdk.NewInt(1 * atomsToUatoms)
+	msg := bank.NewMsgMultiSend(
+		[]bank.Input{
+			bank.NewInput(addrs[0], sdk.Coins{sdk.NewCoin(uatomDenom, totalAmt)}),
+		},
+		[]bank.Output{
+			bank.NewOutput(BurnedCoinsAccAddr, sdk.Coins{sdk.NewCoin(uatomDenom, burnAmt)}),
+			bank.NewOutput(addrs[1], sdk.Coins{sdk.NewCoin(uatomDenom, transAmt)}),
+		},
+	)
+
+	res := handler(input.ctx, msg)
+	require.True(t, res.IsOK(), "expected successful message execution: %v", res.Log)
+
+	from := input.accKeeper.GetAccount(input.ctx, addrs[0])
+	balance := initAmt.Sub(totalAmt)
+	require.Equal(t, from.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+
+	to := input.accKeeper.GetAccount(input.ctx, addrs[1])
+	balance = initAmt.Add(transAmt)
+	require.Equal(t, to.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+
+	burn := input.accKeeper.GetAccount(input.ctx, BurnedCoinsAccAddr)
+	require.Equal(t, burn.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, burnAmt)})
+}
+
+func TestHandlerMsgMultiSendTransfersDisabledInvalidBurn(t *testing.T) {
+	input := createTestInput(t)
+	input.bankKeeper.SetSendEnabled(input.ctx, false)
+
+	handler := NewHandler(input.bankKeeper)
+	totalAmt := sdk.NewInt(15 * atomsToUatoms)
+	burnAmt := sdk.NewInt(10 * atomsToUatoms)
+	transAmt := sdk.NewInt(5 * atomsToUatoms)
+	msg := bank.NewMsgMultiSend(
+		[]bank.Input{
+			bank.NewInput(addrs[0], sdk.Coins{sdk.NewCoin(uatomDenom, totalAmt)}),
+		},
+		[]bank.Output{
+			bank.NewOutput(BurnedCoinsAccAddr, sdk.Coins{sdk.NewCoin(uatomDenom, burnAmt)}),
+			bank.NewOutput(addrs[1], sdk.Coins{sdk.NewCoin(uatomDenom, transAmt)}),
+		},
+	)
+
+	res := handler(input.ctx, msg)
+	require.False(t, res.IsOK(), "expected failed message execution: %v", res.Log)
+
+	from := input.accKeeper.GetAccount(input.ctx, addrs[0])
+	require.Equal(t, from.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, initAmt)})
+
+	to := input.accKeeper.GetAccount(input.ctx, addrs[1])
+	require.Equal(t, to.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, initAmt)})
+}
+
+func TestHandlerMsgMultiSendTransfersEnabled(t *testing.T) {
+	input := createTestInput(t)
+	input.bankKeeper.SetSendEnabled(input.ctx, true)
+
+	handler := NewHandler(input.bankKeeper)
+	totalAmt := sdk.NewInt(10 * atomsToUatoms)
+	outAmt := sdk.NewInt(5 * atomsToUatoms)
+	msg := bank.NewMsgMultiSend(
+		[]bank.Input{
+			bank.NewInput(addrs[0], sdk.Coins{sdk.NewCoin(uatomDenom, totalAmt)}),
+		},
+		[]bank.Output{
+			bank.NewOutput(addrs[1], sdk.Coins{sdk.NewCoin(uatomDenom, outAmt)}),
+			bank.NewOutput(addrs[2], sdk.Coins{sdk.NewCoin(uatomDenom, outAmt)}),
+		},
+	)
+
+	res := handler(input.ctx, msg)
+	require.True(t, res.IsOK(), "expected successful message execution: %v", res.Log)
+
+	from := input.accKeeper.GetAccount(input.ctx, addrs[0])
+	balance := initAmt.Sub(totalAmt)
+	require.Equal(t, from.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+
+	out1 := input.accKeeper.GetAccount(input.ctx, addrs[1])
+	balance = initAmt.Add(outAmt)
+	require.Equal(t, out1.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+
+	out2 := input.accKeeper.GetAccount(input.ctx, addrs[2])
+	balance = initAmt.Add(outAmt)
+	require.Equal(t, out2.GetCoins(), sdk.Coins{sdk.NewCoin(uatomDenom, balance)})
+}