transfer (total escrow): add invariant for total escrow

modules/apps/transfer/keeper/invariants.go

@@ -0,0 +1,51 @@
+package keeper
+
+import (
+	"fmt"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+
+	"github.com/cosmos/ibc-go/v7/modules/apps/transfer/types"
+)
+
+// RegisterInvariants registers all transfer invariants
+func RegisterInvariants(ir sdk.InvariantRegistry, k *Keeper) {
+	ir.RegisterRoute(types.ModuleName, "total-escrow-per-denom",
+		TotalEscrowPerDenomInvariants(k))
+}
+
+// AllInvariants runs all invariants of the transfer module.
+func AllInvariants(k *Keeper) sdk.Invariant {
+	return func(ctx sdk.Context) (string, bool) {
+		return TotalEscrowPerDenomInvariants(k)(ctx)
+	}
+}
+
+// TotalEscrowPerDenomInvariants checks that the total amount escrowed for
+// each denom is not smaller than the amount stored in the state entry.
+func TotalEscrowPerDenomInvariants(k *Keeper) sdk.Invariant {
+	return func(ctx sdk.Context) (string, bool) {
+		var actualTotalEscrowed sdk.Coins
+
+		expectedTotalEscrowed := k.GetAllTotalEscrowed(ctx)
+
+		portID := k.GetPort(ctx)
+		transferChannels := k.channelKeeper.GetAllChannelsWithPortPrefix(ctx, portID)
+		for _, channel := range transferChannels {
+			escrowAddress := types.GetEscrowAddress(portID, channel.ChannelId)
+			escrowBalances := k.bankKeeper.GetAllBalances(ctx, escrowAddress)
+
+			actualTotalEscrowed = actualTotalEscrowed.Add(escrowBalances...)
+		}
+
+		// the actual escrowed amount must be greater than or equal to the expected amount for all denominations
+		if !actualTotalEscrowed.IsAllGTE(expectedTotalEscrowed) {
+			return sdk.FormatInvariant(
+				types.ModuleName,
+				"total escrow per denom invariance",
+				fmt.Sprintf("found denom(s) with total escrow amount lower than expected:\nactual total escrowed: %s\nexpected total escrowed: %s", actualTotalEscrowed, expectedTotalEscrowed)), true
+		}
+
+		return "", false
+	}
+}

modules/apps/transfer/keeper/invariants_test.go

@@ -0,0 +1,71 @@
+package keeper_test
+
+import (
+	"cosmossdk.io/math"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/ibc-go/v7/modules/apps/transfer/keeper"
+	"github.com/cosmos/ibc-go/v7/modules/apps/transfer/types"
+)
+
+func (suite *KeeperTestSuite) TestTotalEscrowPerDenomInvariant() {
+	testCases := []struct {
+		name     string
+		malleate func()
+		expPass  bool
+	}{
+		{
+			"success",
+			func() {},
+			true,
+		},
+		{
+			"fails with broken invariant",
+			func() {
+				// set amount for denom higher than actual value in escrow
+				amount := math.NewInt(200)
+				suite.chainA.GetSimApp().TransferKeeper.SetTotalEscrowForDenom(suite.chainA.GetContext(), sdk.DefaultBondDenom, amount)
+			},
+			false,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+
+		suite.Run(tc.name, func() {
+			suite.SetupTest() // reset
+			path := NewTransferPath(suite.chainA, suite.chainB)
+			suite.coordinator.Setup(path)
+
+			amount := math.NewInt(100)
+
+			// send coins from chain A to chain B so that we have them in escrow
+			coin := sdk.NewCoin(sdk.DefaultBondDenom, amount)
+			msg := types.NewMsgTransfer(
+				path.EndpointA.ChannelConfig.PortID,
+				path.EndpointA.ChannelID,
+				coin,
+				suite.chainA.SenderAccount.GetAddress().String(),
+				suite.chainB.SenderAccount.GetAddress().String(),
+				suite.chainA.GetTimeoutHeight(), 0, "",
+			)
+
+			res, err := suite.chainA.SendMsgs(msg)
+			suite.Require().NoError(err)
+			suite.Require().NotNil(res)
+
+			tc.malleate()
+
+			out, broken := keeper.TotalEscrowPerDenomInvariants(&suite.chainA.GetSimApp().TransferKeeper)(suite.chainA.GetContext())
+
+			if tc.expPass {
+				suite.Require().False(broken)
+				suite.Require().Empty(out)
+			} else {
+				suite.Require().True(broken)
+				suite.Require().NotEmpty(out)
+			}
+		})
+	}
+}

modules/apps/transfer/module.go

@@ -94,8 +94,8 @@ func NewAppModule(k keeper.Keeper) AppModule {
 }
 
 // RegisterInvariants implements the AppModule interface
-func (AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
-	// TODO
+func (am AppModule) RegisterInvariants(ir sdk.InvariantRegistry) {
+	keeper.RegisterInvariants(ir, &am.keeper)
 }
 
 // RegisterServices registers module services.