Add a JunoBurn module/wasm plugin

app/keepers/keepers.go

@@ -81,6 +81,7 @@ import (
 	upgradekeeper "github.com/cosmos/cosmos-sdk/x/upgrade/keeper"
 	upgradetypes "github.com/cosmos/cosmos-sdk/x/upgrade/types"
 
+	junoburn "github.com/CosmosContracts/juno/v17/x/burn"
 	dripkeeper "github.com/CosmosContracts/juno/v17/x/drip/keeper"
 	driptypes "github.com/CosmosContracts/juno/v17/x/drip/types"
 	feesharekeeper "github.com/CosmosContracts/juno/v17/x/feeshare/keeper"
@@ -122,6 +123,7 @@ var maccPerms = map[string][]string{
 	tokenfactorytypes.ModuleName:   {authtypes.Minter, authtypes.Burner},
 	globalfee.ModuleName:           nil,
 	buildertypes.ModuleName:        nil,
+	junoburn.ModuleName:            nil,
 }
 
 type AppKeepers struct {
@@ -518,6 +520,15 @@ func NewAppKeepers(
 		})
 	wasmOpts = append(wasmOpts, querierOpts)
 
+	// burnOverride := wasmkeeper.WithMessageHandlerDecorator(func(old wasmkeeper.Messenger) wasmkeeper.Messenger {
+	// 	customBurner := burn.NewBurnerPlugin(appKeepers.BankKeeper)
+	// 	return wasmkeeper.NewBurnCoinMessageHandler(customBurner)
+	// })
+
+	junoBurnerPlugin := junoburn.NewBurnerPlugin(appKeepers.BankKeeper)
+	burnOverride := wasmkeeper.WithMessageHandler(wasmkeeper.NewBurnCoinMessageHandler(junoBurnerPlugin))
+	wasmOpts = append(wasmOpts, burnOverride)
+
 	appKeepers.WasmKeeper = wasmkeeper.NewKeeper(
 		appCodec,
 		appKeepers.keys[wasmtypes.StoreKey],

x/burn/README.md

@@ -0,0 +1,7 @@
+# x/burn
+
+This is a 'module' used solely to burn tokens properly in line with our x/mint module requirements.
+
+## Burn address
+
+- juno1mj7t69y4r2adl3cnuq8y9uundkzawvx6avu7nj

x/burn/burner.go

@@ -0,0 +1,31 @@
+package burn
+
+import (
+	wasmtypes "github.com/CosmWasm/wasmd/x/wasm/types"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	bankkeeper "github.com/cosmos/cosmos-sdk/x/bank/keeper"
+)
+
+// used to override Wasmd's NewBurnCoinMessageHandler
+
+type BurnerWasmPlugin struct {
+	bk bankkeeper.Keeper
+}
+
+var _ wasmtypes.Burner = &BurnerWasmPlugin{}
+
+func NewBurnerPlugin(bk bankkeeper.Keeper) *BurnerWasmPlugin {
+	return &BurnerWasmPlugin{bk: bk}
+}
+
+func (k *BurnerWasmPlugin) BurnCoins(_ sdk.Context, _ string, _ sdk.Coins) error {
+	// instead of burning, we just hold in balance and subtract from the x/mint module's total supply
+	// return k.bk.BurnCoins(ctx, moduleName, amt)
+	return nil
+}
+
+func (k *BurnerWasmPlugin) SendCoinsFromAccountToModule(ctx sdk.Context, senderAddr sdk.AccAddress, _ string, amt sdk.Coins) error {
+	// we override the default send to instead sent to the "junoburn" module. Then we subtract that from the x/mint module in its query
+	return k.bk.SendCoinsFromAccountToModule(ctx, senderAddr, ModuleName, amt)
+}

x/burn/constants.go

@@ -0,0 +1,5 @@
+package burn
+
+const (
+	ModuleName = "junoburn"
+)

x/mint/abci.go

@@ -6,6 +6,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/telemetry"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
+	junoburn "github.com/CosmosContracts/juno/v17/x/burn"
 	"github.com/CosmosContracts/juno/v17/x/mint/keeper"
 	"github.com/CosmosContracts/juno/v17/x/mint/types"
 )
@@ -26,8 +27,12 @@ func BeginBlocker(ctx sdk.Context, k keeper.Keeper) {
 	params := k.GetParams(ctx)
 	currentBlock := uint64(ctx.BlockHeight())
 
+	// get juno's burn module account
+	acc := k.GetAccountKeeper().GetModuleAccount(ctx, junoburn.ModuleName)
+	totalBurnedAmt := k.GetBalance(ctx, acc.GetAddress(), params.MintDenom)
+
 	// fetch current total supply
-	totalSupply := k.TokenSupply(ctx, params.MintDenom)
+	totalSupply := k.TokenSupply(ctx, params.MintDenom).Sub(totalBurnedAmt)
 
 	// check if we need to change phase
 	nextPhase := minter.NextPhase(params, totalSupply)

x/mint/keeper/keeper.go

@@ -19,6 +19,7 @@ type Keeper struct {
 	cdc              codec.BinaryCodec
 	storeKey         storetypes.StoreKey
 	stakingKeeper    types.StakingKeeper
+	accountKeeper    types.AccountKeeper
 	bankKeeper       types.BankKeeper
 	feeCollectorName string
 
@@ -47,6 +48,7 @@ func NewKeeper(
 		storeKey:         key,
 		stakingKeeper:    sk,
 		bankKeeper:       bk,
+		accountKeeper:    ak,
 		feeCollectorName: feeCollectorName,
 		authority:        authority,
 	}
@@ -110,6 +112,10 @@ func (k Keeper) GetParams(ctx sdk.Context) (p types.Params) {
 	return p
 }
 
+func (k Keeper) GetAccountKeeper() types.AccountKeeper {
+	return k.accountKeeper
+}
+
 // ______________________________________________________________________
 
 // StakingTokenSupply implements an alias call to the underlying staking keeper's
@@ -124,6 +130,12 @@ func (k Keeper) TokenSupply(ctx sdk.Context, denom string) math.Int {
 	return k.bankKeeper.GetSupply(ctx, denom).Amount
 }
 
+// GetBalance implements an alias call to the underlying bank keeper's
+// GetBalance to be used in BeginBlocker.
+func (k Keeper) GetBalance(ctx sdk.Context, address sdk.AccAddress, denom string) math.Int {
+	return k.bankKeeper.GetBalance(ctx, address, denom).Amount
+}
+
 // BondedRatio implements an alias call to the underlying staking keeper's
 // BondedRatio to be used in BeginBlocker.
 func (k Keeper) BondedRatio(ctx sdk.Context) sdk.Dec {

x/mint/types/expected_keepers.go

@@ -26,6 +26,7 @@ type AccountKeeper interface {
 // dependencies.
 type BankKeeper interface {
 	GetSupply(ctx sdk.Context, denom string) sdk.Coin
+	GetBalance(ctx sdk.Context, addr sdk.AccAddress, denom string) sdk.Coin
 	SendCoinsFromModuleToAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins) error
 	SendCoinsFromModuleToModule(ctx sdk.Context, senderModule, recipientModule string, amt sdk.Coins) error
 	MintCoins(ctx sdk.Context, name string, amt sdk.Coins) error