Add hooks to governance actions (#9133)

* add governance hooks

* fix lint

* fix lint

* CHANGELOG

* sh -> gh

* improve comments

* add test

* add more tests

* rename two of the hooks

Co-authored-by: ahmedaly113 <ahmedaly113@outlook.com>

CHANGELOG.md

@@ -43,6 +43,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (rosetta) [\#8729](https://github.com/cosmos/cosmos-sdk/pull/8729) Data API fully supports balance tracking. Construction API can now construct any message supported by the application.
 * [\#8754](https://github.com/cosmos/cosmos-sdk/pull/8875) Added support for reverse iteration to pagination.
 * [#9088](https://github.com/cosmos/cosmos-sdk/pull/9088) Added implementation to ADR-28 Derived Addresses.
+* [\#9133](https://github.com/cosmos/cosmos-sdk/pull/9133) Added hooks for governance actions.
 
 ### Client Breaking Changes
 * [\#8363](https://github.com/cosmos/cosmos-sdk/pull/8363) Addresses no longer have a fixed 20-byte length. From the SDK modules' point of view, any 1-255 bytes-long byte array is a valid address.

simapp/app.go

@@ -273,11 +273,17 @@ func NewSimApp(
 		AddRoute(paramproposal.RouterKey, params.NewParamChangeProposalHandler(app.ParamsKeeper)).
 		AddRoute(distrtypes.RouterKey, distr.NewCommunityPoolSpendProposalHandler(app.DistrKeeper)).
 		AddRoute(upgradetypes.RouterKey, upgrade.NewSoftwareUpgradeProposalHandler(app.UpgradeKeeper))
-	app.GovKeeper = govkeeper.NewKeeper(
+	govKeeper := govkeeper.NewKeeper(
 		appCodec, keys[govtypes.StoreKey], app.GetSubspace(govtypes.ModuleName), app.AccountKeeper, app.BankKeeper,
 		&stakingKeeper, govRouter,
 	)
 
+	app.GovKeeper = *govKeeper.SetHooks(
+		govtypes.NewMultiGovHooks(
+		// register the governance hooks
+		),
+	)
+
 	// create evidence keeper with router
 	evidenceKeeper := evidencekeeper.NewKeeper(
 		appCodec, keys[evidencetypes.StoreKey], &app.StakingKeeper, app.SlashingKeeper,

x/gov/abci.go

@@ -21,6 +21,9 @@ func EndBlocker(ctx sdk.Context, keeper keeper.Keeper) {
 		keeper.DeleteProposal(ctx, proposal.ProposalId)
 		keeper.DeleteDeposits(ctx, proposal.ProposalId)
 
+		// called when proposal become inactive
+		keeper.AfterProposalFailedMinDeposit(ctx, proposal.ProposalId)
+
 		ctx.EventManager().EmitEvent(
 			sdk.NewEvent(
 				types.EventTypeInactiveProposal,
@@ -89,6 +92,9 @@ func EndBlocker(ctx sdk.Context, keeper keeper.Keeper) {
 		keeper.SetProposal(ctx, proposal)
 		keeper.RemoveFromActiveProposalQueue(ctx, proposal.ProposalId, proposal.VotingEndTime)
 
+		// when proposal become active
+		keeper.AfterProposalVotingPeriodEnded(ctx, proposal.ProposalId)
+
 		logger.Info(
 			"proposal tallied",
 			"proposal", proposal.ProposalId,

x/gov/keeper/deposit.go

@@ -150,6 +150,9 @@ func (keeper Keeper) AddDeposit(ctx sdk.Context, proposalID uint64, depositorAdd
 		deposit = types.NewDeposit(proposalID, depositorAddr, depositAmount)
 	}
 
+	// called when deposit has been added to a proposal, however the proposal may not be active
+	keeper.AfterProposalDeposit(ctx, proposalID, depositorAddr)
+
 	ctx.EventManager().EmitEvent(
 		sdk.NewEvent(
 			types.EventTypeProposalDeposit,

x/gov/keeper/hooks.go

@@ -0,0 +1,44 @@
+package keeper
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/gov/types"
+)
+
+// Implements GovHooks interface
+var _ types.GovHooks = Keeper{}
+
+// AfterProposalSubmission - call hook if registered
+func (keeper Keeper) AfterProposalSubmission(ctx sdk.Context, proposalID uint64) {
+	if keeper.hooks != nil {
+		keeper.hooks.AfterProposalSubmission(ctx, proposalID)
+	}
+}
+
+// AfterProposalDeposit - call hook if registered
+func (keeper Keeper) AfterProposalDeposit(ctx sdk.Context, proposalID uint64, depositorAddr sdk.AccAddress) {
+	if keeper.hooks != nil {
+		keeper.hooks.AfterProposalDeposit(ctx, proposalID, depositorAddr)
+	}
+}
+
+// AfterProposalVote - call hook if registered
+func (keeper Keeper) AfterProposalVote(ctx sdk.Context, proposalID uint64, voterAddr sdk.AccAddress) {
+	if keeper.hooks != nil {
+		keeper.hooks.AfterProposalVote(ctx, proposalID, voterAddr)
+	}
+}
+
+// AfterProposalFailedMinDeposit - call hook if registered
+func (keeper Keeper) AfterProposalFailedMinDeposit(ctx sdk.Context, proposalID uint64) {
+	if keeper.hooks != nil {
+		keeper.hooks.AfterProposalFailedMinDeposit(ctx, proposalID)
+	}
+}
+
+// AfterProposalVotingPeriodEnded - call hook if registered
+func (keeper Keeper) AfterProposalVotingPeriodEnded(ctx sdk.Context, proposalID uint64) {
+	if keeper.hooks != nil {
+		keeper.hooks.AfterProposalVotingPeriodEnded(ctx, proposalID)
+	}
+}

x/gov/keeper/hooks_test.go

@@ -0,0 +1,96 @@
+package keeper_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/gov"
+	"github.com/cosmos/cosmos-sdk/x/gov/keeper"
+	"github.com/cosmos/cosmos-sdk/x/gov/types"
+)
+
+var _ types.GovHooks = &MockGovHooksReceiver{}
+
+// GovHooks event hooks for governance proposal object (noalias)
+type MockGovHooksReceiver struct {
+	AfterProposalSubmissionValid        bool
+	AfterProposalDepositValid           bool
+	AfterProposalVoteValid              bool
+	AfterProposalFailedMinDepositValid  bool
+	AfterProposalVotingPeriodEndedValid bool
+}
+
+func (h *MockGovHooksReceiver) AfterProposalSubmission(ctx sdk.Context, proposalID uint64) {
+	h.AfterProposalSubmissionValid = true
+}
+
+func (h *MockGovHooksReceiver) AfterProposalDeposit(ctx sdk.Context, proposalID uint64, depositorAddr sdk.AccAddress) {
+	h.AfterProposalDepositValid = true
+}
+
+func (h *MockGovHooksReceiver) AfterProposalVote(ctx sdk.Context, proposalID uint64, voterAddr sdk.AccAddress) {
+	h.AfterProposalVoteValid = true
+}
+func (h *MockGovHooksReceiver) AfterProposalFailedMinDeposit(ctx sdk.Context, proposalID uint64) {
+	h.AfterProposalFailedMinDepositValid = true
+}
+func (h *MockGovHooksReceiver) AfterProposalVotingPeriodEnded(ctx sdk.Context, proposalID uint64) {
+	h.AfterProposalVotingPeriodEndedValid = true
+}
+
+func TestHooks(t *testing.T) {
+	app := simapp.Setup(false)
+	ctx := app.BaseApp.NewContext(false, tmproto.Header{})
+
+	minDeposit := app.GovKeeper.GetDepositParams(ctx).MinDeposit
+	addrs := simapp.AddTestAddrs(app, ctx, 1, minDeposit[0].Amount)
+
+	govHooksReceiver := MockGovHooksReceiver{}
+
+	app.GovKeeper = *keeper.UpdateHooks(&app.GovKeeper,
+		types.NewMultiGovHooks(
+			&govHooksReceiver,
+		),
+	)
+
+	require.False(t, govHooksReceiver.AfterProposalSubmissionValid)
+	require.False(t, govHooksReceiver.AfterProposalDepositValid)
+	require.False(t, govHooksReceiver.AfterProposalVoteValid)
+	require.False(t, govHooksReceiver.AfterProposalFailedMinDepositValid)
+	require.False(t, govHooksReceiver.AfterProposalVotingPeriodEndedValid)
+
+	tp := TestProposal
+	_, err := app.GovKeeper.SubmitProposal(ctx, tp)
+	require.NoError(t, err)
+	require.True(t, govHooksReceiver.AfterProposalSubmissionValid)
+
+	newHeader := ctx.BlockHeader()
+	newHeader.Time = ctx.BlockHeader().Time.Add(app.GovKeeper.GetDepositParams(ctx).MaxDepositPeriod).Add(time.Duration(1) * time.Second)
+	ctx = ctx.WithBlockHeader(newHeader)
+	gov.EndBlocker(ctx, app.GovKeeper)
+
+	require.True(t, govHooksReceiver.AfterProposalFailedMinDepositValid)
+
+	p2, err := app.GovKeeper.SubmitProposal(ctx, tp)
+	require.NoError(t, err)
+
+	activated, err := app.GovKeeper.AddDeposit(ctx, p2.ProposalId, addrs[0], minDeposit)
+	require.True(t, activated)
+	require.NoError(t, err)
+	require.True(t, govHooksReceiver.AfterProposalDepositValid)
+
+	err = app.GovKeeper.AddVote(ctx, p2.ProposalId, addrs[0], types.NewNonSplitVoteOption(types.OptionYes))
+	require.NoError(t, err)
+	require.True(t, govHooksReceiver.AfterProposalVoteValid)
+
+	newHeader = ctx.BlockHeader()
+	newHeader.Time = ctx.BlockHeader().Time.Add(app.GovKeeper.GetVotingParams(ctx).VotingPeriod).Add(time.Duration(1) * time.Second)
+	ctx = ctx.WithBlockHeader(newHeader)
+	gov.EndBlocker(ctx, app.GovKeeper)
+	require.True(t, govHooksReceiver.AfterProposalVotingPeriodEndedValid)
+}

x/gov/keeper/internal_test.go

@@ -0,0 +1,8 @@
+package keeper
+
+import "github.com/cosmos/cosmos-sdk/x/gov/types"
+
+func UpdateHooks(k *Keeper, h types.GovHooks) *Keeper {
+	k.hooks = h
+	return k
+}

x/gov/keeper/keeper.go

@@ -23,6 +23,9 @@ type Keeper struct {
 	// The reference to the DelegationSet and ValidatorSet to get information about validators and delegators
 	sk types.StakingKeeper
 
+	// GovHooks
+	hooks types.GovHooks
+
 	// The (unexposed) keys used to access the stores from the Context.
 	storeKey sdk.StoreKey
 
@@ -66,6 +69,17 @@ func NewKeeper(
 	}
 }
 
+// SetHooks sets the hooks for governance
+func (keeper *Keeper) SetHooks(gh types.GovHooks) *Keeper {
+	if keeper.hooks != nil {
+		panic("cannot set governance hooks twice")
+	}
+
+	keeper.hooks = gh
+
+	return keeper
+}
+
 // Logger returns a module-specific logger.
 func (keeper Keeper) Logger(ctx sdk.Context) log.Logger {
 	return ctx.Logger().With("module", "x/"+types.ModuleName)

x/gov/keeper/proposal.go

@@ -41,6 +41,9 @@ func (keeper Keeper) SubmitProposal(ctx sdk.Context, content types.Content) (typ
 	keeper.InsertInactiveProposalQueue(ctx, proposalID, proposal.DepositEndTime)
 	keeper.SetProposalID(ctx, proposalID+1)
 
+	// called right after a proposal is submitted
+	keeper.AfterProposalSubmission(ctx, proposalID)
+
 	ctx.EventManager().EmitEvent(
 		sdk.NewEvent(
 			types.EventTypeSubmitProposal,

x/gov/keeper/vote.go

@@ -27,6 +27,9 @@ func (keeper Keeper) AddVote(ctx sdk.Context, proposalID uint64, voterAddr sdk.A
 	vote := types.NewVote(proposalID, voterAddr, options)
 	keeper.SetVote(ctx, vote)
 
+	// called after a vote on a proposal is cast
+	keeper.AfterProposalVote(ctx, proposalID, voterAddr)
+
 	ctx.EventManager().EmitEvent(
 		sdk.NewEvent(
 			types.EventTypeProposalVote,

x/gov/types/expected_keepers.go

@@ -48,3 +48,16 @@ type BankKeeper interface {
 	SendCoinsFromAccountToModule(ctx sdk.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error
 	BurnCoins(ctx sdk.Context, name string, amt sdk.Coins) error
 }
+
+// Event Hooks
+// These can be utilized to communicate between a governance keeper and another
+// keepers.
+
+// GovHooks event hooks for governance proposal object (noalias)
+type GovHooks interface {
+	AfterProposalSubmission(ctx sdk.Context, proposalID uint64)                            // Must be called after proposal is submitted
+	AfterProposalDeposit(ctx sdk.Context, proposalID uint64, depositorAddr sdk.AccAddress) // Must be called after a deposit is made
+	AfterProposalVote(ctx sdk.Context, proposalID uint64, voterAddr sdk.AccAddress)        // Must be called after a vote on a proposal is cast
+	AfterProposalFailedMinDeposit(ctx sdk.Context, proposalID uint64)                      // Must be called when proposal fails to reach min deposit
+	AfterProposalVotingPeriodEnded(ctx sdk.Context, proposalID uint64)                     // Must be called when proposal's finishes it's voting period
+}

x/gov/types/hooks.go

@@ -0,0 +1,42 @@
+package types
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+var _ GovHooks = MultiGovHooks{}
+
+// combine multiple governance hooks, all hook functions are run in array sequence
+type MultiGovHooks []GovHooks
+
+func NewMultiGovHooks(hooks ...GovHooks) MultiGovHooks {
+	return hooks
+}
+
+func (h MultiGovHooks) AfterProposalSubmission(ctx sdk.Context, proposalID uint64) {
+	for i := range h {
+		h[i].AfterProposalSubmission(ctx, proposalID)
+	}
+}
+
+func (h MultiGovHooks) AfterProposalDeposit(ctx sdk.Context, proposalID uint64, depositorAddr sdk.AccAddress) {
+	for i := range h {
+		h[i].AfterProposalDeposit(ctx, proposalID, depositorAddr)
+	}
+}
+
+func (h MultiGovHooks) AfterProposalVote(ctx sdk.Context, proposalID uint64, voterAddr sdk.AccAddress) {
+	for i := range h {
+		h[i].AfterProposalVote(ctx, proposalID, voterAddr)
+	}
+}
+func (h MultiGovHooks) AfterProposalFailedMinDeposit(ctx sdk.Context, proposalID uint64) {
+	for i := range h {
+		h[i].AfterProposalFailedMinDeposit(ctx, proposalID)
+	}
+}
+func (h MultiGovHooks) AfterProposalVotingPeriodEnded(ctx sdk.Context, proposalID uint64) {
+	for i := range h {
+		h[i].AfterProposalVotingPeriodEnded(ctx, proposalID)
+	}
+}