feat: add selective gas exemption whitelist (#1332)

# Related Github tickets

- VolumeFi#2487

# Background

This change introduces a new governance concept: a whitelist of gas
exempt addresses. The list can be updated by creating a
`MsgUpdateParams` vote on the `paloma` module.

Every member address of the list will be exempt from paying gas fees on
the chain.

The change also brings some QOL improvements in the integration testing
package.

# Testing completed

- [x] test coverage exists or has been added/updated
- [x] tested in a private testnet

# Breaking changes

- [x] I have checked my code for breaking changes
- [x] If there are breaking changes, there is a supporting migration.

app/app.go

@@ -139,6 +139,7 @@ import (
 	palomaclient "github.com/palomachain/paloma/v2/x/paloma/client"
 	palomamodulekeeper "github.com/palomachain/paloma/v2/x/paloma/keeper"
 	palomamoduletypes "github.com/palomachain/paloma/v2/x/paloma/types"
+	palomatypes "github.com/palomachain/paloma/v2/x/paloma/types"
 	schedulermodule "github.com/palomachain/paloma/v2/x/scheduler"
 	schedulerbindings "github.com/palomachain/paloma/v2/x/scheduler/bindings"
 	schedulermodulekeeper "github.com/palomachain/paloma/v2/x/scheduler/keeper"
@@ -623,6 +624,7 @@ func New(
 		app.ValsetKeeper,
 		app.UpgradeKeeper,
 		authcodec.NewBech32Codec(chainparams.ValidatorAddressPrefix),
+		authorityAddress,
 	)
 
 	app.PalomaKeeper.ExternalChains = []palomamoduletypes.ExternalChainSupporterKeeper{
@@ -1069,6 +1071,7 @@ func New(
 	anteDecorators = append(anteDecorators,
 		palomamodule.NewLogMsgDecorator(app.appCodec),
 		palomamodule.NewVerifyAuthorisedSignatureDecorator(app.FeeGrantKeeper),
+		palomamodule.NewGasExemptAddressDecorator(app.PalomaKeeper),
 	)
 	anteHandler := sdk.ChainAnteDecorators(
 		anteDecorators...,
@@ -1274,20 +1277,21 @@ func initParamsKeeper(appCodec codec.BinaryCodec, legacyAmino *codec.LegacyAmino
 
 	paramsKeeper.Subspace(authtypes.ModuleName)
 	paramsKeeper.Subspace(banktypes.ModuleName)
-	paramsKeeper.Subspace(stakingtypes.ModuleName)
-	paramsKeeper.Subspace(minttypes.ModuleName)
+	paramsKeeper.Subspace(consensusmoduletypes.ModuleName)
+	paramsKeeper.Subspace(crisistypes.ModuleName)
 	paramsKeeper.Subspace(distrtypes.ModuleName)
-	paramsKeeper.Subspace(slashingtypes.ModuleName)
+	paramsKeeper.Subspace(evmmoduletypes.ModuleName)
 	paramsKeeper.Subspace(govtypes.ModuleName)
-	paramsKeeper.Subspace(crisistypes.ModuleName)
+	paramsKeeper.Subspace(metrixmoduletypes.ModuleName)
+	paramsKeeper.Subspace(minttypes.ModuleName)
+	paramsKeeper.Subspace(palomatypes.ModuleName)
 	paramsKeeper.Subspace(schedulermoduletypes.ModuleName)
-	paramsKeeper.Subspace(consensusmoduletypes.ModuleName)
-	paramsKeeper.Subspace(valsetmoduletypes.ModuleName)
-	paramsKeeper.Subspace(wasmtypes.ModuleName)
-	paramsKeeper.Subspace(evmmoduletypes.ModuleName)
 	paramsKeeper.Subspace(skywaymoduletypes.ModuleName).WithKeyTable(skywaymoduletypes.ParamKeyTable())
-	paramsKeeper.Subspace(metrixmoduletypes.ModuleName)
+	paramsKeeper.Subspace(slashingtypes.ModuleName)
+	paramsKeeper.Subspace(stakingtypes.ModuleName)
 	paramsKeeper.Subspace(tokenfactorymoduletypes.ModuleName)
+	paramsKeeper.Subspace(valsetmoduletypes.ModuleName)
+	paramsKeeper.Subspace(wasmtypes.ModuleName)
 
 	paramsKeeper.Subspace(ibcexported.ModuleName).WithKeyTable(keyTable)
 	paramsKeeper.Subspace(ibctransfertypes.ModuleName).WithKeyTable(ibctransfertypes.ParamKeyTable())

proto/palomachain/paloma/paloma/params.proto

@@ -2,8 +2,13 @@ syntax = "proto3";
 package palomachain.paloma.paloma;
 
 import "gogoproto/gogo.proto";
+import "cosmos_proto/cosmos.proto";
 
 option go_package = "github.com/palomachain/paloma/v2/x/paloma/types";
 
 // Params defines the parameters for the module.
-message Params { option (gogoproto.goproto_stringer) = false; }
+message Params { 
+  option (gogoproto.goproto_stringer) = false; 
+
+  repeated string GasExemptAddresses = 1 [ (cosmos_proto.scalar) = "cosmos.AddressString" ];
+}

proto/palomachain/paloma/paloma/tx.proto

@@ -1,11 +1,15 @@
 syntax = "proto3";
 package palomachain.paloma.paloma;
 
+import "gogoproto/gogo.proto";
+import "google/api/annotations.proto";
+
 import "cosmos/base/v1beta1/coin.proto";
 import "cosmos/msg/v1/msg.proto";
 import "cosmos_proto/cosmos.proto";
-import "gogoproto/gogo.proto";
+
 import "palomachain/paloma/valset/common.proto";
+import "palomachain/paloma/paloma/params.proto";
 
 option go_package = "github.com/palomachain/paloma/v2/x/paloma/types";
 
@@ -23,6 +27,11 @@ service Msg {
 
   rpc SetLegacyLightNodeClients(MsgSetLegacyLightNodeClients)
     returns (EmptyResponse);
+
+  rpc UpdateParams(MsgUpdateParams) returns (MsgUpdateParamsResponse) {
+    option (google.api.http).put =
+      "/palomachain/paloma/params";
+    }
 }
 
 message MsgAddStatusUpdate {
@@ -75,3 +84,18 @@ message MsgSetLegacyLightNodeClients {
   palomachain.paloma.valset.MsgMetadata metadata = 1
       [ (gogoproto.nullable) = false ];
 }
+
+message MsgUpdateParams {
+  option (cosmos.msg.v1.signer) = "authority";
+  // authority is the address that controls the module (defaults to x/gov unless
+  // overwritten).
+  string authority = 1 [ (cosmos_proto.scalar) = "cosmos.AddressString" ];
+
+  // NOTE: All parameters must be supplied.
+  Params params = 2 [ (gogoproto.nullable) = false ];
+
+  palomachain.paloma.valset.MsgMetadata metadata = 3
+      [ (gogoproto.nullable) = false ];
+}
+
+message MsgUpdateParamsResponse {}

tests/integration/evm/keeper/genesis_test.go

@@ -6,6 +6,7 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	g "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
+	"github.com/palomachain/paloma/v2/tests/integration/helper"
 	keepertest "github.com/palomachain/paloma/v2/testutil/keeper"
 	"github.com/palomachain/paloma/v2/testutil/nullify"
 	"github.com/palomachain/paloma/v2/x/evm"
@@ -37,12 +38,12 @@ var _ = g.Describe("genesis", func() {
 	var genesisState types.GenesisState
 	var k *keeper.Keeper
 	var ctx sdk.Context
-	var a *fixture
+	var a *helper.Fixture
 
 	g.BeforeEach(func() {
-		a = initFixture(t)
-		ctx = a.ctx.WithBlockHeight(5)
-		k = &a.evmKeeper
+		a = helper.InitFixture(t)
+		ctx = a.Ctx.WithBlockHeight(5)
+		k = &a.EvmKeeper
 	})
 
 	g.BeforeEach(func() {
@@ -71,7 +72,7 @@ var _ = g.Describe("genesis", func() {
 							[]byte("abc"),
 						)
 						Expect(err).To(BeNil())
-						err = a.evmKeeper.SetFeeManagerAddress(ctx, ci.ChainReferenceID, cDummyFeeMgrAddress)
+						err = a.EvmKeeper.SetFeeManagerAddress(ctx, ci.ChainReferenceID, cDummyFeeMgrAddress)
 						require.NoError(t, err)
 					}
 				}