feat(mint): update mint param type (piplabs#182)

* feat(mint): update param type

* feat(mint): make param value consistent among example and tests

client/x/mint/README.md

@@ -32,7 +32,11 @@ message Params {
   // type of coin to mint
   string mint_denom = 1;
   // inflation amount per year
-  uint64 inflations_per_year = 2;
+  string inflations_per_year = 2 [
+    (cosmos_proto.scalar)  = "cosmos.Dec",
+    (gogoproto.customtype) = "cosmossdk.io/math.LegacyDec",
+    (gogoproto.nullable)   = false
+  ];
   // expected blocks per year
   uint64 blocks_per_year = ;
 }
@@ -58,11 +62,11 @@ type InflationCalculationFn func(ctx sdk.Context, minter Minter, params Params,
 
 The minting module contains the following parameters:
 
-| Key                 | Type            | Example                      |
-|---------------------|-----------------|------------------------------|
-| MintDenom           | string          | "stake"                      |
-| InflationsPerYear   | string (dec)    | "24625000000000000"          |
-| BlocksPerYear       | string (uint64) | "6311520"                    |
+| Key                 | Type            | Example                                |
+|---------------------|-----------------|----------------------------------------|
+| MintDenom           | string          | "stake"                                |
+| InflationsPerYear   | string (dec)    | "24625000000000000.000000000000000000" |
+| BlocksPerYear       | string (uint64) | "6311520"                              |
 
 
 ## Events

client/x/mint/keeper/genesis_test.go

@@ -4,6 +4,7 @@ package keeper_test
 import (
 	"testing"
 
+	"cosmossdk.io/math"
 	storetypes "cosmossdk.io/store/types"
 
 	"github.com/cosmos/cosmos-sdk/codec"
@@ -62,7 +63,7 @@ func (s *GenesisTestSuite) TestImportExportGenesis() {
 	genesisState := types.DefaultGenesisState()
 	genesisState.Params = types.NewParams(
 		"testDenom",
-		24625000_000_000_000,
+		math.LegacyNewDec(24625000000000000.000000000000000000),
 		uint64(60*60*8766/5),
 	)
 

client/x/mint/types/genesis.go

@@ -15,7 +15,7 @@ type InflationCalculationFn func(ctx context.Context, params Params, bondedRatio
 
 // DefaultInflationCalculationFn is the default function used to calculate inflation.
 func DefaultInflationCalculationFn(_ context.Context, params Params, _ math.LegacyDec) math.LegacyDec {
-	return math.LegacyNewDec(int64(params.InflationsPerYear)).Quo(math.LegacyNewDec(int64(params.BlocksPerYear)))
+	return params.InflationsPerYear.Quo(math.LegacyNewDec(int64(params.BlocksPerYear)))
 }
 
 // NewGenesisState creates a new GenesisState object.

client/x/mint/types/mint.proto

@@ -4,6 +4,8 @@ package client.x.mint.types;
 option go_package = "client/x/mint/types";
 
 import "amino/amino.proto";
+import "cosmos_proto/cosmos.proto";
+import "gogoproto/gogo.proto";
 
 // Params defines the parameters for the x/mint module.
 message Params {
@@ -12,7 +14,11 @@ message Params {
   // type of coin to mint
   string mint_denom = 1;
   // inflation amount per year
-  uint64 inflations_per_year = 2;
+  string inflations_per_year = 2 [
+    (cosmos_proto.scalar)  = "cosmos.Dec",
+    (gogoproto.customtype) = "cosmossdk.io/math.LegacyDec",
+    (gogoproto.nullable)   = false
+  ];
   // expected blocks per year
   uint64 blocks_per_year = 3;
 }

client/x/mint/types/params.go

@@ -13,7 +13,7 @@ import (
 )
 
 // NewParams returns Params instance with the given values.
-func NewParams(mintDenom string, inflationsPerYear uint64, blocksPerYear uint64) Params {
+func NewParams(mintDenom string, inflationsPerYear math.LegacyDec, blocksPerYear uint64) Params {
 	return Params{
 		MintDenom:         mintDenom,
 		InflationsPerYear: inflationsPerYear,
@@ -25,7 +25,7 @@ func NewParams(mintDenom string, inflationsPerYear uint64, blocksPerYear uint64)
 func DefaultParams() Params {
 	return Params{
 		MintDenom:         sdk.DefaultBondDenom,
-		InflationsPerYear: 24625000_000_000_000,
+		InflationsPerYear: math.LegacyNewDec(24625000000000000.000000000000000000),
 		BlocksPerYear:     uint64(60 * 60 * 8766 / 5), // assuming 5 second block times
 	}
 }