configure a limit on the number of blocks when a validator can receive rewards

Author: MarkCherepovskyi

proto/cosmos/mint/v1beta1/mint.proto

@@ -15,7 +15,8 @@ message Params {
   // expected blocks per month
   uint64 blocks_per_month = 2;
   // block when no additional tokens will be minted
+  uint64 end_block = 3;
 
-  cosmos.base.v1beta1.Coin month_reward = 3
+  cosmos.base.v1beta1.Coin month_reward = 4
   [(gogoproto.nullable) = false, (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Coin"];
 }

x/mint/abci.go

@@ -15,6 +15,10 @@ func BeginBlocker(ctx sdk.Context, k keeper.Keeper) {
 	// fetch stored minter & params
 	params := k.GetParams(ctx)
 
+	// skip if all tokens already minted
+	if uint64(ctx.BlockHeight()) >= params.EndBlock {
+		return
+	}
 	monthReward := sdk.NewDecFromInt(params.MonthReward.Amount)
 	mintedAmount := monthReward.QuoInt(sdk.NewInt(int64(params.BlocksPerMonth)))