fix: Simulation is not deterministic due to GenTx (backport #12374)

CHANGELOG.md

@@ -40,6 +40,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Bug Fixes
 
 * (x/mint) [#12384](https://github.com/cosmos/cosmos-sdk/pull/12384) Ensure `GoalBonded` must be positive when performing `x/mint` parameter validation.
+* (simapp) [#12437](https://github.com/cosmos/cosmos-sdk/pull/12437) fix the non-determinstic behavior in simulations caused by `GenTx` and check 
+empty coins slice before it is used to create `banktype.MsgSend`.
 
 ## [v0.45.6](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.45.6) - 2022-06-28
 

simapp/helpers/test_helpers.go

@@ -2,7 +2,6 @@ package helpers
 
 import (
 	"math/rand"
-	"time"
 
 	"github.com/cosmos/cosmos-sdk/client"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
@@ -19,12 +18,10 @@ const (
 )
 
 // GenTx generates a signed mock transaction.
-func GenTx(gen client.TxConfig, msgs []sdk.Msg, feeAmt sdk.Coins, gas uint64, chainID string, accNums, accSeqs []uint64, priv ...cryptotypes.PrivKey) (sdk.Tx, error) {
+func GenTx(r *rand.Rand, gen client.TxConfig, msgs []sdk.Msg, feeAmt sdk.Coins, gas uint64, chainID string, accNums, accSeqs []uint64, priv ...cryptotypes.PrivKey) (sdk.Tx, error) {
 	sigs := make([]signing.SignatureV2, len(priv))
 
 	// create a random length memo
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
-
 	memo := simulation.RandStringOfLength(r, simulation.RandIntBetween(r, 0, 100))
 
 	signMode := gen.SignModeHandler().DefaultMode()

simapp/test_helpers.go

@@ -5,6 +5,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"strconv"
 	"testing"
 	"time"
@@ -327,6 +328,7 @@ func SignCheckDeliver(
 ) (sdk.GasInfo, *sdk.Result, error) {
 
 	tx, err := helpers.GenTx(
+		rand.New(rand.NewSource(time.Now().UnixNano())),
 		txCfg,
 		msgs,
 		sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 0)},
@@ -377,6 +379,7 @@ func GenSequenceOfTxs(txGen client.TxConfig, msgs []sdk.Msg, accNums []uint64, i
 	var err error
 	for i := 0; i < numToGenerate; i++ {
 		txs[i], err = helpers.GenTx(
+			rand.New(rand.NewSource(time.Now().UnixNano())),
 			txGen,
 			msgs,
 			sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 0)},

x/authz/simulation/operations.go

@@ -115,6 +115,7 @@ func SimulateMsgGrant(ak authz.AccountKeeper, bk authz.BankKeeper, _ keeper.Keep
 		}
 		txCfg := simappparams.MakeTestEncodingConfig().TxConfig
 		tx, err := helpers.GenTx(
+			r,
 			txCfg,
 			[]sdk.Msg{msg},
 			fees,
@@ -181,6 +182,7 @@ func SimulateMsgRevoke(ak authz.AccountKeeper, bk authz.BankKeeper, k keeper.Kee
 		txCfg := simappparams.MakeTestEncodingConfig().TxConfig
 		account := ak.GetAccount(ctx, granterAddr)
 		tx, err := helpers.GenTx(
+			r,
 			txCfg,
 			[]sdk.Msg{&msg},
 			fees,
@@ -239,6 +241,10 @@ func SimulateMsgExec(ak authz.AccountKeeper, bk authz.BankKeeper, k keeper.Keepe
 
 		granterspendableCoins := bk.SpendableCoins(ctx, granterAddr)
 		coins := simtypes.RandSubsetCoins(r, granterspendableCoins)
+		// if coins slice is empty, we can not create valid banktype.MsgSend
+		if len(coins) == 0 {
+			return simtypes.NoOpMsg(authz.ModuleName, TypeMsgExec, "empty coins slice"), nil, nil
+		}
 		// Check send_enabled status of each sent coin denom
 		if err := bk.IsSendEnabledCoins(ctx, coins...); err != nil {
 			return simtypes.NoOpMsg(authz.ModuleName, TypeMsgExec, err.Error()), nil, nil
@@ -271,6 +277,7 @@ func SimulateMsgExec(ak authz.AccountKeeper, bk authz.BankKeeper, k keeper.Keepe
 		txCfg := simappparams.MakeTestEncodingConfig().TxConfig
 		granteeAcc := ak.GetAccount(ctx, granteeAddr)
 		tx, err := helpers.GenTx(
+			r,
 			txCfg,
 			[]sdk.Msg{&msgExec},
 			fees,

x/bank/simulation/operations.go

@@ -60,6 +60,10 @@ func SimulateMsgSend(ak types.AccountKeeper, bk keeper.Keeper) simtypes.Operatio
 		accs []simtypes.Account, chainID string,
 	) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
 		from, to, coins, skip := randomSendFields(r, ctx, accs, bk, ak)
+		// if coins slice is empty, we can not create valid types.MsgSend
+		if len(coins) == 0 {
+			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgSend, "empty coins slice"), nil, nil
+		}
 
 		// Check send_enabled status of each coin denom
 		if err := bk.IsSendEnabledCoins(ctx, coins...); err != nil {
@@ -94,6 +98,10 @@ func SimulateMsgSendToModuleAccount(ak types.AccountKeeper, bk keeper.Keeper, mo
 
 		spendable := bk.SpendableCoins(ctx, from.Address)
 		coins := simtypes.RandSubsetCoins(r, spendable)
+		// if coins slice is empty, we can not create valid types.MsgSend
+		if len(coins) == 0 {
+			return simtypes.NoOpMsg(types.ModuleName, types.TypeMsgSend, "empty coins slice"), nil, nil
+		}
 
 		// Check send_enabled status of each coin denom
 		if err := bk.IsSendEnabledCoins(ctx, coins...); err != nil {
@@ -139,6 +147,7 @@ func sendMsgSend(
 	}
 	txGen := simappparams.MakeTestEncodingConfig().TxConfig
 	tx, err := helpers.GenTx(
+		r,
 		txGen,
 		[]sdk.Msg{msg},
 		fees,
@@ -355,6 +364,7 @@ func sendMsgMultiSend(
 
 	txGen := simappparams.MakeTestEncodingConfig().TxConfig
 	tx, err := helpers.GenTx(
+		r,
 		txGen,
 		[]sdk.Msg{msg},
 		fees,

x/distribution/simulation/operations.go

@@ -231,6 +231,7 @@ func SimulateMsgFundCommunityPool(ak types.AccountKeeper, bk types.BankKeeper, k
 		msg := types.NewMsgFundCommunityPool(fundAmount, funder.Address)
 
 		txCtx := simulation.OperationInput{
+			R:             r,
 			App:           app,
 			TxGen:         simappparams.MakeTestEncodingConfig().TxConfig,
 			Cdc:           nil,

x/genutil/gentx_test.go

@@ -3,7 +3,9 @@ package genutil_test
 import (
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/suite"
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
@@ -234,6 +236,7 @@ func (suite *GenTxTestSuite) TestDeliverGenTxs() {
 
 				msg := banktypes.NewMsgSend(addr1, addr2, sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 1)})
 				tx, err := helpers.GenTx(
+					rand.New(rand.NewSource(time.Now().UnixNano())),
 					suite.encodingConfig.TxConfig,
 					[]sdk.Msg{msg},
 					sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 10)},

x/gov/simulation/operations.go

@@ -156,6 +156,7 @@ func SimulateMsgSubmitProposal(
 
 		txGen := simappparams.MakeTestEncodingConfig().TxConfig
 		tx, err := helpers.GenTx(
+			r,
 			txGen,
 			[]sdk.Msg{msg},
 			fees,
@@ -242,6 +243,7 @@ func SimulateMsgDeposit(ak types.AccountKeeper, bk types.BankKeeper, k keeper.Ke
 		}
 
 		txCtx := simulation.OperationInput{
+			R:             r,
 			App:           app,
 			TxGen:         simappparams.MakeTestEncodingConfig().TxConfig,
 			Cdc:           nil,

x/simulation/util.go

@@ -101,6 +101,7 @@ func GenAndDeliverTxWithRandFees(txCtx OperationInput) (simtypes.OperationMsg, [
 func GenAndDeliverTx(txCtx OperationInput, fees sdk.Coins) (simtypes.OperationMsg, []simtypes.FutureOperation, error) {
 	account := txCtx.AccountKeeper.GetAccount(txCtx.Context, txCtx.SimAccount.Address)
 	tx, err := helpers.GenTx(
+		txCtx.R,
 		txCtx.TxGen,
 		[]sdk.Msg{txCtx.Msg},
 		fees,

x/slashing/simulation/operations.go

@@ -90,6 +90,7 @@ func SimulateMsgUnjail(ak types.AccountKeeper, bk types.BankKeeper, k keeper.Kee
 
 		txGen := simappparams.MakeTestEncodingConfig().TxConfig
 		tx, err := helpers.GenTx(
+			r,
 			txGen,
 			[]sdk.Msg{msg},
 			fees,

x/staking/simulation/operations.go

@@ -152,6 +152,7 @@ func SimulateMsgCreateValidator(ak types.AccountKeeper, bk types.BankKeeper, k k
 		}
 
 		txCtx := simulation.OperationInput{
+			R:             r,
 			App:           app,
 			TxGen:         simappparams.MakeTestEncodingConfig().TxConfig,
 			Cdc:           nil,
@@ -276,6 +277,7 @@ func SimulateMsgDelegate(ak types.AccountKeeper, bk types.BankKeeper, k keeper.K
 		msg := types.NewMsgDelegate(simAccount.Address, val.GetOperator(), bondAmt)
 
 		txCtx := simulation.OperationInput{
+			R:             r,
 			App:           app,
 			TxGen:         simappparams.MakeTestEncodingConfig().TxConfig,
 			Cdc:           nil,