update parameter migration script to keep old brokerAddress

proto/elys/parameter/params.proto

@@ -24,3 +24,21 @@ message Params {
   string broker_address = 4;
 	int64 total_blocks_per_year = 5;
 }
+
+message LegacyParams {
+  option (gogoproto.goproto_stringer) = false;
+
+  string min_commission_rate = 1 [
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+    (gogoproto.nullable) = false
+  ];
+  string max_voting_power = 2 [
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
+    (gogoproto.nullable) = false
+  ];
+  string min_self_delegation = 3 [
+    (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Int",
+    (gogoproto.nullable) = false
+  ];
+  string broker_address = 4;
+}

x/parameter/keeper/params.go

@@ -24,3 +24,16 @@ func (k Keeper) SetParams(ctx sdk.Context, params types.Params) {
 	b := k.cdc.MustMarshal(&params)
 	store.Set([]byte(types.ParamsKey), b)
 }
+
+// GetParams get all parameters as types.Params
+func (k Keeper) GetLegacyParams(ctx sdk.Context) (params types.LegacyParams) {
+	store := ctx.KVStore(k.storeKey)
+
+	b := store.Get([]byte(types.ParamsKey))
+	if b == nil {
+		return
+	}
+
+	k.cdc.MustUnmarshal(b, &params)
+	return
+}

x/parameter/migrations/v3_migration.go

@@ -7,12 +7,13 @@ import (
 
 func (m Migrator) V3Migration(ctx sdk.Context) error {
 	// reset params
+	legacy := m.keeper.GetLegacyParams(ctx)
 	params := types.NewParams(
-		sdk.NewDecWithPrec(5, 2),  // min commission 0.05
-		sdk.NewDecWithPrec(66, 2), // max voting power 0.66
-		sdk.NewInt(1),             // min self delegation
-		"elys1m3hduhk4uzxn8mxuvpz02ysndxfwgy5mq60h4c34qqn67xud584qeee3m4", // broker address
-		6307200, // total blocks per year
+		legacy.MinCommissionRate, // min commission 0.05
+		legacy.MaxVotingPower,    // max voting power 0.66
+		legacy.MinSelfDelegation, // min self delegation
+		legacy.BrokerAddress,     // broker address
+		6307200,                  // total blocks per year
 	)
 	m.keeper.SetParams(ctx, params)
 

x/parameter/types/params.go

@@ -100,3 +100,9 @@ func validateBrokerAddress(i interface{}) error {
 	}
 	return nil
 }
+
+// String implements the Stringer interface.
+func (p LegacyParams) String() string {
+	out, _ := yaml.Marshal(p)
+	return string(out)
+}