Update DefaultHistoricalEntries to 100 (#6059)

* Update DefaultHistoricalEntries to 1000

* hist entries sims and comment on simapp

* changelog and godoc

* update sim param change

* update default to 100

Co-authored-by: Federico Kunze <federico.kunze94@gmail.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: 3 people

CHANGELOG.md

@@ -222,6 +222,7 @@ functionality that requires an online connection.
 * (x/evidence) [\#5961](https://github.com/cosmos/cosmos-sdk/issues/5961) Add `StoreDecoder` simulation for evidence module.
 * (x/auth/ante) [\#6040](https://github.com/cosmos/cosmos-sdk/pull/6040) `AccountKeeper` interface used for `NewAnteHandler` and handler's decorators to add support of using custom `AccountKeeper` implementations.
 * (simulation) [\#6002](https://github.com/cosmos/cosmos-sdk/pull/6002) Add randomized consensus params into simulation.
+* (x/staking) [\#6059](https://github.com/cosmos/cosmos-sdk/pull/6059) Updated `HistoricalEntries` parameter default to 100.
 
 ## [v0.38.3] - 2020-04-09
 

simapp/app.go

@@ -280,6 +280,7 @@ func NewSimApp(
 	// During begin block slashing happens after distr.BeginBlocker so that
 	// there is nothing left over in the validator fee pool, so as to keep the
 	// CanWithdrawInvariant invariant.
+	// NOTE: staking module is required if HistoricalEntries param > 0
 	app.mm.SetOrderBeginBlockers(
 		upgrade.ModuleName, mint.ModuleName, distr.ModuleName, slashing.ModuleName,
 		evidence.ModuleName, staking.ModuleName, ibc.ModuleName,

x/staking/simulation/genesis.go

@@ -17,8 +17,9 @@ import (
 
 // Simulation parameter constants
 const (
-	UnbondingTime = "unbonding_time"
-	MaxValidators = "max_validators"
+	unbondingTime     = "unbonding_time"
+	maxValidators     = "max_validators"
+	historicalEntries = "historical_entries"
 )
 
 // GenUnbondingTime randomized UnbondingTime
@@ -31,26 +32,37 @@ func GenMaxValidators(r *rand.Rand) (maxValidators uint32) {
 	return uint32(r.Intn(250) + 1)
 }
 
+// GetHistEntries randomized HistoricalEntries between 0-100.
+func GetHistEntries(r *rand.Rand) uint32 {
+	return uint32(r.Intn(int(types.DefaultHistoricalEntries + 1)))
+}
+
 // RandomizedGenState generates a random GenesisState for staking
 func RandomizedGenState(simState *module.SimulationState) {
 	// params
 	var unbondTime time.Duration
 	simState.AppParams.GetOrGenerate(
-		simState.Cdc, UnbondingTime, &unbondTime, simState.Rand,
+		simState.Cdc, unbondingTime, &unbondTime, simState.Rand,
 		func(r *rand.Rand) { unbondTime = GenUnbondingTime(r) },
 	)
 
-	var maxValidators uint32
+	var maxVals uint32
+	simState.AppParams.GetOrGenerate(
+		simState.Cdc, maxValidators, &maxVals, simState.Rand,
+		func(r *rand.Rand) { maxVals = GenMaxValidators(r) },
+	)
+
+	var histEntries uint32
 	simState.AppParams.GetOrGenerate(
-		simState.Cdc, MaxValidators, &maxValidators, simState.Rand,
-		func(r *rand.Rand) { maxValidators = GenMaxValidators(r) },
+		simState.Cdc, historicalEntries, &histEntries, simState.Rand,
+		func(r *rand.Rand) { histEntries = GetHistEntries(r) },
 	)
 
 	// NOTE: the slashing module need to be defined after the staking module on the
 	// NewSimulationManager constructor for this to work
 	simState.UnbondTime = unbondTime
 
-	params := types.NewParams(simState.UnbondTime, maxValidators, 7, 3, sdk.DefaultBondDenom)
+	params := types.NewParams(simState.UnbondTime, maxVals, 7, histEntries, sdk.DefaultBondDenom)
 
 	// validators & delegations
 	var (

x/staking/simulation/params.go

@@ -12,24 +12,24 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/staking/types"
 )
 
-const (
-	keyMaxValidators = "MaxValidators"
-	keyUnbondingTime = "UnbondingTime"
-)
-
 // ParamChanges defines the parameters that can be modified by param change proposals
 // on the simulation
 func ParamChanges(r *rand.Rand) []simtypes.ParamChange {
 	return []simtypes.ParamChange{
-		simulation.NewSimParamChange(types.ModuleName, keyMaxValidators,
+		simulation.NewSimParamChange(types.ModuleName, string(types.KeyMaxValidators),
 			func(r *rand.Rand) string {
 				return fmt.Sprintf("%d", GenMaxValidators(r))
 			},
 		),
-		simulation.NewSimParamChange(types.ModuleName, keyUnbondingTime,
+		simulation.NewSimParamChange(types.ModuleName, string(types.KeyUnbondingTime),
 			func(r *rand.Rand) string {
 				return fmt.Sprintf("\"%d\"", GenUnbondingTime(r))
 			},
 		),
+		simulation.NewSimParamChange(types.ModuleName, string(types.KeyHistoricalEntries),
+			func(r *rand.Rand) string {
+				return fmt.Sprintf("%d", GetHistEntries(r))
+			},
+		),
 	}
 }

x/staking/types/params.go

@@ -26,9 +26,10 @@ const (
 	// Default maximum entries in a UBD/RED pair
 	DefaultMaxEntries uint32 = 7
 
-	// DefaultHistorical entries is 0 since it must only be non-zero for
-	// IBC connected chains
-	DefaultHistoricalEntries uint32 = 0
+	// DefaultHistorical entries is 100. Apps that don't use IBC can ignore this
+	// value by not adding the staking module to the application module manager's
+	// SetOrderBeginBlockers.
+	DefaultHistoricalEntries uint32 = 100
 )
 
 // nolint - Keys for parameter access