feat(x/mint): Add max supply param (#19895)

Co-authored-by: Marko <[email protected]>

Author: 2 people

api/cosmos/mint/v1beta1/mint.pulsar.go

@@ -59,4 +59,10 @@ message Params {
   ];
   // expected blocks per year
   uint64 blocks_per_year = 6;
+  // maximum supply for the token
+  string max_supply = 7 [
+    (cosmos_proto.scalar)  = "cosmos.Int",
+    (gogoproto.customtype) = "cosmossdk.io/math.Int",
+    (gogoproto.nullable)   = false
+  ];
 }

proto/cosmos/mint/v1beta1/mint.proto

@@ -29,7 +29,7 @@ func (s *E2ETestSuite) TestQueryGRPC() {
 			&minttypes.QueryParamsResponse{},
 			&minttypes.QueryParamsResponse{
 				Params: minttypes.NewParams("stake", math.LegacyNewDecWithPrec(13, 2), math.LegacyNewDecWithPrec(100, 2),
-					math.LegacyNewDec(1), math.LegacyNewDecWithPrec(67, 2), (60 * 60 * 8766 / 5)),
+					math.LegacyNewDec(1), math.LegacyNewDecWithPrec(67, 2), (60 * 60 * 8766 / 5), math.ZeroInt()),
 			},
 		},
 		{

tests/e2e/mint/grpc.go

@@ -28,3 +28,5 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ## [v0.2.0-rc.1](https://github.com/cosmos/cosmos-sdk/releases/tag/tools/benchmark/v0.2.0-rc.1) - 2024-12-18
 
 * [#22778](https://github.com/cosmos/cosmos-sdk/pull/22778) - Initial commit
+* [19896](https://github.com/cosmos/cosmos-sdk/pull/19896) Added a new max supply genesis param to existing params.
+

tools/benchmark/CHANGELOG.md

@@ -140,17 +140,21 @@ https://github.com/cosmos/cosmos-sdk/blob/v0.47.0-rc1/proto/cosmos/mint/v1beta1/
 
 The mint module stores its params in state with the prefix of `0x01`,
 it can be updated with governance or the address with authority.
+**Note:** With the latest update, the addition of the `MaxSupply` parameter allows controlling the maximum supply of tokens minted by the module. 
+A value of `0` indicates an unlimited supply.
 
 * Params: `mint/params -> legacy_amino(params)`
 
 ```protobuf reference
-https://github.com/cosmos/cosmos-sdk/blob/v0.47.0-rc1/proto/cosmos/mint/v1beta1/mint.proto#L26-L59
+https://github.com/cosmos/cosmos-sdk/blob/7068d0da52d954430054768b2c56aff44666933b/x/mint/proto/cosmos/mint/v1beta1/mint.proto#L26-L68
 ```
 
 ## Begin-Block
 
 Minting parameters are recalculated and inflation paid at the beginning of each block.
 
+The minting logic in the `BeginBlocker` function provides an optional feature for controlling token minting based on the maximum allowable supply (MaxSupply). This feature allows users to adjust the minting process according to their specific requirements and use cases. However, it's important to note that the MaxSupply parameter is independent of the minting process and assumes that any adjustments to the total supply, including burning tokens, are handled by external modules.
+
 ### Inflation rate calculation
 
 Inflation rate is calculated using an "inflation calculation function" that's
@@ -213,15 +217,17 @@ BlockProvision(params Params) sdk.Coin {
 ## Parameters
 
 The minting module contains the following parameters:
+Note: `0` indicates unlimited supply for MaxSupply param
 
-| Key                 | Type            | Example                |
-|---------------------|-----------------|------------------------|
-| MintDenom           | string          | "uatom"                |
-| InflationRateChange | string (dec)    | "0.130000000000000000" |
-| InflationMax        | string (dec)    | "0.200000000000000000" |
-| InflationMin        | string (dec)    | "0.070000000000000000" |
-| GoalBonded          | string (dec)    | "0.670000000000000000" |
-| BlocksPerYear       | string (uint64) | "6311520"              |
+| Key                 | Type             | Example                |
+|---------------------|------------------|------------------------|
+| MintDenom           | string           | "uatom"                |
+| InflationRateChange | string (dec)     | "0.130000000000000000" |
+| InflationMax        | string (dec)     | "0.200000000000000000" |
+| InflationMin        | string (dec)     | "0.070000000000000000" |
+| GoalBonded          | string (dec)     | "0.670000000000000000" |
+| BlocksPerYear       | string (uint64)  | "6311520"              |
+| MaxSupply           | string (math.Int)| "0"                    |
 
 
 ## Events
@@ -309,6 +315,7 @@ inflation_max: "0.200000000000000000"
 inflation_min: "0.070000000000000000"
 inflation_rate_change: "0.130000000000000000"
 mint_denom: stake
+max_supply: "0"
 ```
 
 ### gRPC
@@ -383,7 +390,8 @@ Example Output:
     "inflationMax": "200000000000000000",
     "inflationMin": "70000000000000000",
     "goalBonded": "670000000000000000",
-    "blocksPerYear": "6311520"
+    "blocksPerYear": "6311520",
+    "maxSupply": "0",
   }
 }
 ```
@@ -454,7 +462,8 @@ Example Output:
     "inflationMax": "200000000000000000",
     "inflationMin": "70000000000000000",
     "goalBonded": "670000000000000000",
-    "blocksPerYear": "6311520"
+    "blocksPerYear": "6311520",
+    "maxSupply": "0",
   }
 }
 ```

x/mint/README.md

@@ -0,0 +1,18 @@
+package mint
+
+import (
+	"context"
+
+	"github.com/cosmos/cosmos-sdk/telemetry"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/mint/keeper"
+	"github.com/cosmos/cosmos-sdk/x/mint/types"
+)
+
+// BeginBlocker mints new tokens for the previous block.
+func BeginBlocker(ctx context.Context, k keeper.Keeper) error {
+	defer telemetry.ModuleMeasureSince(types.ModuleName, telemetry.Now(), telemetry.MetricKeyBeginBlocker)
+
+	sdkCtx := sdk.UnwrapSDKContext(ctx)
+	return k.MintFn(sdkCtx)
+}

x/mint/keeper/abci.go

@@ -69,6 +69,7 @@ func (s *GenesisTestSuite) TestImportExportGenesis() {
 		math.LegacyNewDecWithPrec(9, 2),
 		math.LegacyNewDecWithPrec(69, 2),
 		uint64(60*60*8766/5),
+		math.ZeroInt(),
 	)
 
 	s.keeper.InitGenesis(s.sdkCtx, s.accountKeeper, genesisState)

x/mint/keeper/genesis_test.go

@@ -1,9 +1,12 @@
 package keeper
 
 import (
+	"context"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/mint/exported"
 	v2 "github.com/cosmos/cosmos-sdk/x/mint/migrations/v2"
+	"github.com/cosmos/cosmos-sdk/x/mint/types"
 )
 
 // Migrator is a struct for handling in-place state migrations.
@@ -27,3 +30,24 @@ func NewMigrator(k Keeper, ss exported.Subspace) Migrator {
 func (m Migrator) Migrate1to2(ctx sdk.Context) error {
 	return v2.Migrate(ctx, m.keeper.storeService.OpenKVStore(ctx), m.legacySubspace, m.keeper.cdc)
 }
+
+// Migrate2to3 migrates the x/mint module state from the consensus version 2 to
+// version 3.
+func (m Migrator) Migrate2to3(ctx context.Context) error {
+	params, err := m.keeper.Params.Get(ctx)
+	if err != nil {
+		return err
+	}
+
+	// Initialize the new MaxSupply parameter with the default value
+	defaultParams := types.DefaultParams()
+	params.MaxSupply = defaultParams.MaxSupply
+
+	// Set the updated params
+	err = m.keeper.Params.Set(ctx, params)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}