feat!: change Coin storage model

CHANGELOG.md

@@ -101,6 +101,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (x/bank) [\#9611](https://github.com/cosmos/cosmos-sdk/pull/9611) Introduce a new index to act as a reverse index between a denomination and address allowing to query for
   token holders of a specific denomination. `DenomOwners` is updated to use the new reverse index.
+* (x/bank) [\#9832] (https://github.com/cosmos/cosmos-sdk/pull/9832) Account balance is stored as `sdk.Int` rather than `sdk.Coin`.
 
 ## [v0.43.0-rc0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.43.0-rc0) - 2021-06-25
 

types/query/filtered_pagination_test.go

@@ -171,7 +171,7 @@ func (s *paginationTestSuite) TestReverseFilteredPaginations() {
 }
 
 func ExampleFilteredPaginate() {
-	app, ctx, appCodec := setupTest()
+	app, ctx, _ := setupTest()
 
 	var balances sdk.Coins
 	for i := 0; i < numBalances; i++ {
@@ -200,16 +200,16 @@ func ExampleFilteredPaginate() {
 
 	var balResult sdk.Coins
 	pageRes, err := query.FilteredPaginate(accountStore, pageReq, func(key []byte, value []byte, accumulate bool) (bool, error) {
-		var bal sdk.Coin
-		err := appCodec.Unmarshal(value, &bal)
+		var amount sdk.Int
+		err := amount.Unmarshal(value)
 		if err != nil {
 			return false, err
 		}
 
-		// filter balances with amount greater than 100
-		if bal.Amount.Int64() > int64(100) {
+		// filter amount greater than 100
+		if amount.Int64() > int64(100) {
 			if accumulate {
-				balResult = append(balResult, bal)
+				balResult = append(balResult, sdk.NewCoin(string(key), amount))
 			}
 
 			return true, nil
@@ -232,16 +232,16 @@ func execFilterPaginate(store sdk.KVStore, pageReq *query.PageRequest, appCodec
 
 	var balResult sdk.Coins
 	res, err = query.FilteredPaginate(accountStore, pageReq, func(key []byte, value []byte, accumulate bool) (bool, error) {
-		var bal sdk.Coin
-		err := appCodec.Unmarshal(value, &bal)
+		var amount sdk.Int
+		err := amount.Unmarshal(value)
 		if err != nil {
 			return false, err
 		}
 
-		// filter balances with amount greater than 100
-		if bal.Amount.Int64() > int64(100) {
+		// filter amount greater than 100
+		if amount.Int64() > int64(100) {
 			if accumulate {
-				balResult = append(balResult, bal)
+				balResult = append(balResult, sdk.NewCoin(string(key), amount))
 			}
 
 			return true, nil

types/query/pagination_test.go

@@ -319,12 +319,12 @@ func ExamplePaginate() {
 	balancesStore := prefix.NewStore(authStore, types.BalancesPrefix)
 	accountStore := prefix.NewStore(balancesStore, address.MustLengthPrefix(addr1))
 	pageRes, err := query.Paginate(accountStore, request.Pagination, func(key []byte, value []byte) error {
-		var tempRes sdk.Coin
-		err := app.AppCodec().Unmarshal(value, &tempRes)
+		var amount sdk.Int
+		err := amount.Unmarshal(value)
 		if err != nil {
 			return err
 		}
-		balResult = append(balResult, tempRes)
+		balResult = append(balResult, sdk.NewCoin(string(key), amount))
 		return nil
 	})
 	if err != nil { // should return no error

x/bank/keeper/grpc_query.go

@@ -59,13 +59,12 @@ func (k BaseKeeper) AllBalances(ctx context.Context, req *types.QueryAllBalances
 	balances := sdk.NewCoins()
 	accountStore := k.getAccountStore(sdkCtx, addr)
 
-	pageRes, err := query.Paginate(accountStore, req.Pagination, func(_, value []byte) error {
-		var result sdk.Coin
-		err := k.cdc.Unmarshal(value, &result)
-		if err != nil {
+	pageRes, err := query.Paginate(accountStore, req.Pagination, func(key, value []byte) error {
+		var amount sdk.Int
+		if err := amount.Unmarshal(value); err != nil {
 			return err
 		}
-		balances = append(balances, result)
+		balances = append(balances, sdk.NewCoin(string(key), amount))
 		return nil
 	})
 
@@ -187,7 +186,7 @@ func (k BaseKeeper) DenomOwners(
 		req.Pagination,
 		func(key []byte, value []byte, accumulate bool) (bool, error) {
 			if accumulate {
-				address, err := types.AddressFromBalancesStore(key)
+				address, _, err := types.AddressAndDenomFromBalancesStore(key)
 				if err != nil {
 					return false, err
 				}

x/bank/keeper/send.go

@@ -243,8 +243,11 @@ func (k BaseSendKeeper) initBalances(ctx sdk.Context, addr sdk.AccAddress, balan
 
 		// x/bank invariants prohibit persistence of zero balances
 		if !balance.IsZero() {
-			bz := k.cdc.MustMarshal(&balance)
-			accountStore.Set([]byte(balance.Denom), bz)
+			amount, err := balance.Amount.Marshal()
+			if err != nil {
+				return err
+			}
+			accountStore.Set([]byte(balance.Denom), amount)
 
 			denomPrefixStore, ok := denomPrefixStores[balance.Denom]
 			if !ok {
@@ -278,8 +281,11 @@ func (k BaseSendKeeper) setBalance(ctx sdk.Context, addr sdk.AccAddress, balance
 		accountStore.Delete([]byte(balance.Denom))
 		denomPrefixStore.Delete(address.MustLengthPrefix(addr))
 	} else {
-		bz := k.cdc.MustMarshal(&balance)
-		accountStore.Set([]byte(balance.Denom), bz)
+		amount, err := balance.Amount.Marshal()
+		if err != nil {
+			return err
+		}
+		accountStore.Set([]byte(balance.Denom), amount)
 
 		// Store a reverse index from denomination to account address with a
 		// sentinel value.

x/bank/keeper/view.go

@@ -98,16 +98,17 @@ func (k BaseViewKeeper) GetAccountsBalances(ctx sdk.Context) []types.Balance {
 // by address.
 func (k BaseViewKeeper) GetBalance(ctx sdk.Context, addr sdk.AccAddress, denom string) sdk.Coin {
 	accountStore := k.getAccountStore(ctx, addr)
-
+	amount := sdk.ZeroInt()
 	bz := accountStore.Get([]byte(denom))
 	if bz == nil {
-		return sdk.NewCoin(denom, sdk.ZeroInt())
+		return sdk.NewCoin(denom, amount)
 	}
 
-	var balance sdk.Coin
-	k.cdc.MustUnmarshal(bz, &balance)
+	if err := amount.Unmarshal(bz); err != nil {
+		panic(err)
+	}
 
-	return balance
+	return sdk.NewCoin(denom, amount)
 }
 
 // IterateAccountBalances iterates over the balances of a single account and
@@ -120,10 +121,12 @@ func (k BaseViewKeeper) IterateAccountBalances(ctx sdk.Context, addr sdk.AccAddr
 	defer iterator.Close()
 
 	for ; iterator.Valid(); iterator.Next() {
-		var balance sdk.Coin
-		k.cdc.MustUnmarshal(iterator.Value(), &balance)
+		var amount sdk.Int
+		if err := amount.Unmarshal(iterator.Value()); err != nil {
+			panic(err)
+		}
 
-		if cb(balance) {
+		if cb(sdk.NewCoin(string(iterator.Key()), amount)) {
 			break
 		}
 	}
@@ -140,18 +143,20 @@ func (k BaseViewKeeper) IterateAllBalances(ctx sdk.Context, cb func(sdk.AccAddre
 	defer iterator.Close()
 
 	for ; iterator.Valid(); iterator.Next() {
-		address, err := types.AddressFromBalancesStore(iterator.Key())
+		address, denom, err := types.AddressAndDenomFromBalancesStore(iterator.Key())
 		if err != nil {
 			k.Logger(ctx).With("key", iterator.Key(), "err", err).Error("failed to get address from balances store")
 			// TODO: revisit, for now, panic here to keep same behavior as in 0.42
 			// ref: https://github.com/cosmos/cosmos-sdk/issues/7409
 			panic(err)
 		}
 
-		var balance sdk.Coin
-		k.cdc.MustUnmarshal(iterator.Value(), &balance)
+		var amount sdk.Int
+		if err := amount.Unmarshal(iterator.Value()); err != nil {
+			panic(err)
+		}
 
-		if cb(address, balance) {
+		if cb(address, sdk.NewCoin(denom, amount)) {
 			break
 		}
 	}

x/bank/migrations/v044/store.go

@@ -6,11 +6,13 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/address"
 	v043 "github.com/cosmos/cosmos-sdk/x/bank/migrations/v043"
+	"github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
 // MigrateStore performs in-place store migrations from v0.43 to v0.44. The
 // migration includes:
 //
+// - Migrate coin storage to save only amount.
 // - Add an additional reverse index from denomination to address.
 func MigrateStore(ctx sdk.Context, storeKey sdk.StoreKey, cdc codec.BinaryCodec) error {
 	store := ctx.KVStore(storeKey)
@@ -36,6 +38,19 @@ func addDenomReverseIndex(store sdk.KVStore, cdc codec.BinaryCodec) error {
 			return err
 		}
 
+		var coin sdk.DecCoin
+		if err := cdc.Unmarshal(oldBalancesIter.Value(), &coin); err != nil {
+			return err
+		}
+
+		bz, err := coin.Amount.Marshal()
+		if err != nil {
+			return err
+		}
+
+		newStore := prefix.NewStore(store, types.CreateAccountBalancesPrefix(addr))
+		newStore.Set([]byte(coin.Denom), bz)
+
 		denomPrefixStore, ok := denomPrefixStores[balance.Denom]
 		if !ok {
 			denomPrefixStore = prefix.NewStore(store, CreateAddressDenomPrefix(balance.Denom))

x/bank/migrations/v044/store_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/types/address"
 	v043 "github.com/cosmos/cosmos-sdk/x/bank/migrations/v043"
 	v044 "github.com/cosmos/cosmos-sdk/x/bank/migrations/v044"
+	"github.com/cosmos/cosmos-sdk/x/bank/types"
 )
 
 func TestMigrateStore(t *testing.T) {
@@ -37,6 +38,14 @@ func TestMigrateStore(t *testing.T) {
 
 	require.NoError(t, v044.MigrateStore(ctx, bankKey, encCfg.Codec))
 
+	for _, b := range balances {
+		addrPrefixStore := prefix.NewStore(store, types.CreateAccountBalancesPrefix(addr))
+		bz := addrPrefixStore.Get([]byte(b.Denom))
+		var expected sdk.Int
+		require.NoError(t, expected.Unmarshal(bz))
+		require.Equal(t, expected, b.Amount)
+	}
+
 	for _, b := range balances {
 		denomPrefixStore := prefix.NewStore(store, v044.CreateAddressDenomPrefix(b.Denom))
 		bz := denomPrefixStore.Get(address.MustLengthPrefix(addr))

x/bank/types/key.go

@@ -37,26 +37,25 @@ func DenomMetadataKey(denom string) []byte {
 	return append(DenomMetadataPrefix, d...)
 }
 
-// AddressFromBalancesStore returns an account address from a balances prefix
+// AddressAndDenomFromBalancesStore returns an account address and denom from a balances prefix
 // store. The key must not contain the prefix BalancesPrefix as the prefix store
 // iterator discards the actual prefix.
 //
-// If invalid key is passed, AddressFromBalancesStore returns ErrInvalidKey.
-func AddressFromBalancesStore(key []byte) (sdk.AccAddress, error) {
+// If invalid key is passed, AddressAndDenomFromBalancesStore returns ErrInvalidKey.
+func AddressAndDenomFromBalancesStore(key []byte) (sdk.AccAddress, string, error) {
 	if len(key) == 0 {
-		return nil, ErrInvalidKey
+		return nil, "", ErrInvalidKey
 	}
 
 	kv.AssertKeyAtLeastLength(key, 1)
 
-	addrLen := key[0]
-	bound := int(addrLen)
+	addrBound := int(key[0])
 
-	if len(key)-1 < bound {
-		return nil, ErrInvalidKey
+	if len(key)-1 < addrBound {
+		return nil, "", ErrInvalidKey
 	}
 
-	return key[1 : bound+1], nil
+	return key[1 : addrBound+1], string(key[addrBound+1:]), nil
 }
 
 // CreateAccountBalancesPrefix creates the prefix for an account's balances.

x/bank/types/key_test.go

@@ -42,7 +42,7 @@ func TestAddressFromBalancesStore(t *testing.T) {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
-			addr, err := types.AddressFromBalancesStore(tc.key)
+			addr, denom, err := types.AddressAndDenomFromBalancesStore(tc.key)
 			if tc.wantErr {
 				assert.Error(t, err)
 				assert.True(t, errors.Is(types.ErrInvalidKey, err))
@@ -51,6 +51,7 @@ func TestAddressFromBalancesStore(t *testing.T) {
 			}
 			if len(tc.expectedKey) > 0 {
 				assert.Equal(t, tc.expectedKey, addr)
+				assert.Equal(t, "stake", denom)
 			}
 		})
 	}