feat(bank): Allow injectable restrictions on bank transfers

CHANGELOG.md

@@ -66,6 +66,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [#14472](https://github.com/cosmos/cosmos-sdk/pull/14356) The recommended metadata format for x/gov and x/group proposals now uses an array of strings (instead of a single string) for the `authors` field.
 * (mempool) [#14484](https://github.com/cosmos/cosmos-sdk/pull/14484) Add priority nonce mempool option for transaction replacement.
 * (client) [#14509](https://github.com/cosmos/cosmos-sdk/pull/#14509) Added `AddKeyringFlags` function.
+* (x/bank) [#14224](https://github.com/cosmos/cosmos-sdk/pull/14224) Allow injection of restrictions on transfers using `AppendSendRestriction` or `PrependSendRestriction`.
 
 ### Improvements
 
@@ -212,6 +213,7 @@ extension interfaces. `module.Manager.Modules` is now of type `map[string]interf
 * (x/auth)[#13780](https://github.com/cosmos/cosmos-sdk/pull/13780) Querying with `id` (type of int64) in `AccountAddressByID` grpc query now throws error, use account-id(type of uint64) instead.
 * (snapshots) [14048](https://github.com/cosmos/cosmos-sdk/pull/14048) Move the Snapshot package to the store package. This is done in an effort group all storage related logic under one package.
 * (baseapp) [#14050](https://github.com/cosmos/cosmos-sdk/pull/14050) refactor `ABCIListener` interface to accept go contexts
+* (x/bank) [#14224](https://github.com/cosmos/cosmos-sdk/pull/14224) `InputOutputCoins` now only allows for a single `Input`.
 
 ### CLI Breaking Changes
 

tests/integration/bank/keeper/keeper_test.go

@@ -425,14 +425,12 @@ func TestInputOutputNewAccount(t *testing.T) {
 	assert.Assert(t, f.accountKeeper.GetAccount(ctx, addr2) == nil)
 	assert.Assert(t, f.bankKeeper.GetAllBalances(ctx, addr2).Empty())
 
-	inputs := []types.Input{
-		{Address: addr1.String(), Coins: sdk.NewCoins(newFooCoin(30), newBarCoin(10))},
-	}
+	input := types.Input{Address: addr1.String(), Coins: sdk.NewCoins(newFooCoin(30), newBarCoin(10))}
 	outputs := []types.Output{
 		{Address: addr2.String(), Coins: sdk.NewCoins(newFooCoin(30), newBarCoin(10))},
 	}
 
-	assert.NilError(t, f.bankKeeper.InputOutputCoins(ctx, inputs, outputs))
+	assert.NilError(t, f.bankKeeper.InputOutputCoins(ctx, input, outputs))
 
 	expected := sdk.NewCoins(newFooCoin(30), newBarCoin(10))
 	acc2Balances := f.bankKeeper.GetAllBalances(ctx, addr2)
@@ -459,9 +457,7 @@ func TestInputOutputCoins(t *testing.T) {
 	acc3 := f.accountKeeper.NewAccountWithAddress(ctx, addr3)
 	f.accountKeeper.SetAccount(ctx, acc3)
 
-	input := []types.Input{
-		{Address: addr1.String(), Coins: sdk.NewCoins(newFooCoin(60), newBarCoin(20))},
-	}
+	input := types.Input{Address: addr1.String(), Coins: sdk.NewCoins(newFooCoin(60), newBarCoin(20))}
 	outputs := []types.Output{
 		{Address: addr2.String(), Coins: sdk.NewCoins(newFooCoin(30), newBarCoin(10))},
 		{Address: addr3.String(), Coins: sdk.NewCoins(newFooCoin(30), newBarCoin(10))},
@@ -472,11 +468,9 @@ func TestInputOutputCoins(t *testing.T) {
 
 	assert.NilError(t, banktestutil.FundAccount(f.bankKeeper, ctx, addr1, balances))
 
-	insufficientInput := []types.Input{
-		{
-			Address: addr1.String(),
-			Coins:   sdk.NewCoins(newFooCoin(300), newBarCoin(100)),
-		},
+	insufficientInput := types.Input{
+		Address: addr1.String(),
+		Coins:   sdk.NewCoins(newFooCoin(300), newBarCoin(100)),
 	}
 	insufficientOutputs := []types.Output{
 		{Address: addr2.String(), Coins: sdk.NewCoins(newFooCoin(300), newBarCoin(100))},
@@ -721,11 +715,9 @@ func TestMsgMultiSendEvents(t *testing.T) {
 	coins := sdk.NewCoins(sdk.NewInt64Coin(fooDenom, 50), sdk.NewInt64Coin(barDenom, 100))
 	newCoins := sdk.NewCoins(sdk.NewInt64Coin(fooDenom, 50))
 	newCoins2 := sdk.NewCoins(sdk.NewInt64Coin(barDenom, 100))
-	input := []types.Input{
-		{
-			Address: addr.String(),
-			Coins:   coins,
-		},
+	input := types.Input{
+		Address: addr.String(),
+		Coins:   coins,
 	}
 	outputs := []types.Output{
 		{Address: addr3.String(), Coins: newCoins},

x/bank/README.md

@@ -236,6 +236,9 @@ accounts. The send keeper does not alter the total supply (mint or burn coins).
 type SendKeeper interface {
     ViewKeeper
 
+    AppendSendRestriction(restriction SendRestrictionFn)
+    PrependSendRestriction(restriction SendRestrictionFn)
+
     InputOutputCoins(ctx sdk.Context, inputs []types.Input, outputs []types.Output) error
     SendCoins(ctx sdk.Context, fromAddr sdk.AccAddress, toAddr sdk.AccAddress, amt sdk.Coins) error
 

x/bank/keeper/export_test.go

@@ -0,0 +1,12 @@
+package keeper
+
+// This file exists in the keeper package to expose some private things
+// for the purpose of testing in the keeper_test package.
+
+func (k BaseSendKeeper) SetSendRestriction(restriction SendRestrictionFn) {
+	k.sendRestriction.Fn = restriction
+}
+
+func (k BaseSendKeeper) GetSendRestrictionFn() SendRestrictionFn {
+	return k.sendRestriction.Fn
+}

x/bank/keeper/keeper.go

@@ -60,8 +60,6 @@ type BaseKeeper struct {
 	mintCoinsRestrictionFn MintingRestrictionFn
 }
 
-type MintingRestrictionFn func(ctx sdk.Context, coins sdk.Coins) error
-
 // GetPaginatedTotalSupply queries for the supply, ignoring 0 coins, with a given pagination
 func (k BaseKeeper) GetPaginatedTotalSupply(ctx sdk.Context, pagination *query.PageRequest) (sdk.Coins, *query.PageResponse, error) {
 	store := ctx.KVStore(k.storeKey)
@@ -109,7 +107,7 @@ func NewBaseKeeper(
 		ak:                     ak,
 		cdc:                    cdc,
 		storeKey:               storeKey,
-		mintCoinsRestrictionFn: func(ctx sdk.Context, coins sdk.Coins) error { return nil },
+		mintCoinsRestrictionFn: NoOpMintingRestrictionFn,
 	}
 }
 
@@ -119,18 +117,7 @@ func NewBaseKeeper(
 //
 //	bankKeeper.WithMintCoinsRestriction(restriction1).WithMintCoinsRestriction(restriction2)
 func (k BaseKeeper) WithMintCoinsRestriction(check MintingRestrictionFn) BaseKeeper {
-	oldRestrictionFn := k.mintCoinsRestrictionFn
-	k.mintCoinsRestrictionFn = func(ctx sdk.Context, coins sdk.Coins) error {
-		err := check(ctx, coins)
-		if err != nil {
-			return err
-		}
-		err = oldRestrictionFn(ctx, coins)
-		if err != nil {
-			return err
-		}
-		return nil
-	}
+	k.mintCoinsRestrictionFn = check.Then(k.mintCoinsRestrictionFn)
 	return k
 }