refactor!: Remove proposer-based rewards

proto/cosmos/distribution/v1beta1/distribution.proto

@@ -1,7 +1,7 @@
 syntax = "proto3";
 package cosmos.distribution.v1beta1;
 
-option go_package            = "github.com/cosmos/cosmos-sdk/x/distribution/types";
+option go_package = "github.com/cosmos/cosmos-sdk/x/distribution/types";
 option (gogoproto.equal_all) = true;
 
 import "gogoproto/gogo.proto";
@@ -16,16 +16,22 @@ message Params {
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
     (gogoproto.nullable)   = false
   ];
+
+  // The base_proposer_reward and bonus_proposer_reward fields are deprecated
+  // and are no longer used in the x/distribution module's reward mechanism.
   string base_proposer_reward = 2 [
     (cosmos_proto.scalar)  = "cosmos.Dec",
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
-    (gogoproto.nullable)   = false
+    (gogoproto.nullable)   = false,
+    deprecated             = true
   ];
   string bonus_proposer_reward = 3 [
     (cosmos_proto.scalar)  = "cosmos.Dec",
     (gogoproto.customtype) = "github.com/cosmos/cosmos-sdk/types.Dec",
-    (gogoproto.nullable)   = false
+    (gogoproto.nullable)   = false,
+    deprecated             = true
   ];
+
   bool withdraw_addr_enabled = 4;
 }
 
@@ -42,32 +48,40 @@ message Params {
 //  read that record)
 //  + one per validator for the zeroeth period, set on initialization
 message ValidatorHistoricalRewards {
-  repeated cosmos.base.v1beta1.DecCoin cumulative_reward_ratio = 1
-      [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins", (gogoproto.nullable) = false];
+  repeated cosmos.base.v1beta1.DecCoin cumulative_reward_ratio = 1 [
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins",
+    (gogoproto.nullable)     = false
+  ];
   uint32 reference_count = 2;
 }
 
 // ValidatorCurrentRewards represents current rewards and current
 // period for a validator kept as a running counter and incremented
 // each block as long as the validator's tokens remain constant.
 message ValidatorCurrentRewards {
-  repeated cosmos.base.v1beta1.DecCoin rewards = 1
-      [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins", (gogoproto.nullable) = false];
+  repeated cosmos.base.v1beta1.DecCoin rewards = 1 [
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins",
+    (gogoproto.nullable)     = false
+  ];
   uint64 period = 2;
 }
 
 // ValidatorAccumulatedCommission represents accumulated commission
 // for a validator kept as a running counter, can be withdrawn at any time.
 message ValidatorAccumulatedCommission {
-  repeated cosmos.base.v1beta1.DecCoin commission = 1
-      [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins", (gogoproto.nullable) = false];
+  repeated cosmos.base.v1beta1.DecCoin commission = 1 [
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins",
+    (gogoproto.nullable)     = false
+  ];
 }
 
 // ValidatorOutstandingRewards represents outstanding (un-withdrawn) rewards
 // for a validator inexpensive to track, allows simple sanity checks.
 message ValidatorOutstandingRewards {
-  repeated cosmos.base.v1beta1.DecCoin rewards = 1
-      [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins", (gogoproto.nullable) = false];
+  repeated cosmos.base.v1beta1.DecCoin rewards = 1 [
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins",
+    (gogoproto.nullable)     = false
+  ];
 }
 
 // ValidatorSlashEvent represents a validator slash event.
@@ -86,13 +100,16 @@ message ValidatorSlashEvent {
 // ValidatorSlashEvents is a collection of ValidatorSlashEvent messages.
 message ValidatorSlashEvents {
   option (gogoproto.goproto_stringer)                 = false;
-  repeated ValidatorSlashEvent validator_slash_events = 1 [(gogoproto.nullable) = false];
+  repeated ValidatorSlashEvent validator_slash_events = 1
+      [(gogoproto.nullable) = false];
 }
 
 // FeePool is the global fee pool for distribution.
 message FeePool {
-  repeated cosmos.base.v1beta1.DecCoin community_pool = 1
-      [(gogoproto.nullable) = false, (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins"];
+  repeated cosmos.base.v1beta1.DecCoin community_pool = 1 [
+    (gogoproto.nullable)     = false,
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins"
+  ];
 }
 
 // CommunityPoolSpendProposal details a proposal for use of community funds,
@@ -107,8 +124,10 @@ message CommunityPoolSpendProposal {
   string   title                           = 1;
   string   description                     = 2;
   string   recipient                       = 3;
-  repeated cosmos.base.v1beta1.Coin amount = 4
-      [(gogoproto.nullable) = false, (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.Coins"];
+  repeated cosmos.base.v1beta1.Coin amount = 4 [
+    (gogoproto.nullable)     = false,
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.Coins"
+  ];
 }
 
 // DelegatorStartingInfo represents the starting info for a delegator reward
@@ -135,8 +154,10 @@ message DelegationDelegatorReward {
 
   string validator_address = 1 [(cosmos_proto.scalar) = "cosmos.AddressString"];
 
-  repeated cosmos.base.v1beta1.DecCoin reward = 2
-      [(gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins", (gogoproto.nullable) = false];
+  repeated cosmos.base.v1beta1.DecCoin reward = 2 [
+    (gogoproto.castrepeated) = "github.com/cosmos/cosmos-sdk/types.DecCoins",
+    (gogoproto.nullable)     = false
+  ];
 }
 
 // CommunityPoolSpendProposalWithDeposit defines a CommunityPoolSpendProposal

x/distribution/abci.go

@@ -12,24 +12,20 @@ import (
 )
 
 // BeginBlocker sets the proposer for determining distribution during endblock
-// and distribute rewards for the previous block
+// and distribute rewards for the previous block.
 func BeginBlocker(ctx sdk.Context, req abci.RequestBeginBlock, k keeper.Keeper) {
 	defer telemetry.ModuleMeasureSince(types.ModuleName, time.Now(), telemetry.MetricKeyBeginBlocker)
 
 	// determine the total power signing the block
-	var previousTotalPower, sumPreviousPrecommitPower int64
+	var previousTotalPower int64
 	for _, voteInfo := range req.LastCommitInfo.GetVotes() {
 		previousTotalPower += voteInfo.Validator.Power
-		if voteInfo.SignedLastBlock {
-			sumPreviousPrecommitPower += voteInfo.Validator.Power
-		}
 	}
 
 	// TODO this is Tendermint-dependent
 	// ref https://github.com/cosmos/cosmos-sdk/issues/3095
 	if ctx.BlockHeight() > 1 {
-		previousProposer := k.GetPreviousProposerConsAddr(ctx)
-		k.AllocateTokens(ctx, sumPreviousPrecommitPower, previousTotalPower, previousProposer, req.LastCommitInfo.GetVotes())
+		k.AllocateTokens(ctx, previousTotalPower, req.LastCommitInfo.GetVotes())
 	}
 
 	// record the proposer for when we payout on the next block

x/distribution/abci_test.go

@@ -4,6 +4,10 @@ import (
 	"testing"
 
 	"cosmossdk.io/math"
+	"github.com/stretchr/testify/require"
+	abci "github.com/tendermint/tendermint/abci/types"
+	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
+
 	"github.com/cosmos/cosmos-sdk/crypto/keys/ed25519"
 	cryptotypes "github.com/cosmos/cosmos-sdk/crypto/types"
 	simtestutil "github.com/cosmos/cosmos-sdk/testutil/sims"
@@ -14,9 +18,6 @@ import (
 	stakingkeeper "github.com/cosmos/cosmos-sdk/x/staking/keeper"
 	"github.com/cosmos/cosmos-sdk/x/staking/teststaking"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
-	"github.com/stretchr/testify/require"
-	abci "github.com/tendermint/tendermint/abci/types"
-	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 )
 
 const (
@@ -116,9 +117,18 @@ func TestVerifyProposerRewardAssignement(t *testing.T) {
 	})
 	require.NotEmpty(t, app.Commit())
 
+	// Note, we used to ensure that the lazy validator's rewards are less than the
+	// non-lazy validator, given the assumption that proposer-based rewards are
+	// used. However, since proposer-based rewards are no longer used, the rewards
+	// should be the same.
+	//
+	// We keep this (modified) assertion in case we'd like to augment the test
+	// in the future.
+	//
+	// Ref: https://github.com/cosmos/cosmos-sdk/pull/12876
 	rewardsValidatorBeforeLazyValidator := distrKeeper.GetValidatorOutstandingRewardsCoins(ctx, validators[lazyValidatorIdx+1].addr)
 	rewardsLazyValidator := distrKeeper.GetValidatorOutstandingRewardsCoins(ctx, validators[lazyValidatorIdx].addr)
 	rewardsValidatorAfterLazyValidator := distrKeeper.GetValidatorOutstandingRewardsCoins(ctx, validators[lazyValidatorIdx+1].addr)
-	require.True(t, rewardsLazyValidator[0].Amount.LT(rewardsValidatorAfterLazyValidator[0].Amount))
+	require.True(t, rewardsLazyValidator[0].Amount.Equal(rewardsValidatorAfterLazyValidator[0].Amount))
 	require.Equal(t, rewardsValidatorBeforeLazyValidator, rewardsValidatorAfterLazyValidator)
 }

x/distribution/keeper/allocation.go

@@ -1,8 +1,6 @@
 package keeper
 
 import (
-	"fmt"
-
 	"cosmossdk.io/math"
 	abci "github.com/tendermint/tendermint/abci/types"
 
@@ -11,15 +9,9 @@ import (
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
 )
 
-// AllocateTokens handles distribution of the collected fees
-// bondedVotes is a list of (validator address, validator voted on last block flag) for all
-// validators in the bonded set.
-func (k Keeper) AllocateTokens(
-	ctx sdk.Context, sumPreviousPrecommitPower, totalPreviousPower int64,
-	previousProposer sdk.ConsAddress, bondedVotes []abci.VoteInfo,
-) {
-	logger := k.Logger(ctx)
-
+// AllocateTokens performs reward and fee distribution to all validators based
+// on the F1 fee distribution specification.
+func (k Keeper) AllocateTokens(ctx sdk.Context, totalPreviousPower int64, bondedVotes []abci.VoteInfo) {
 	// fetch and clear the collected fees for distribution, since this is
 	// called in BeginBlock, collected fees will be from the previous block
 	// (and distributed to the previous proposer)
@@ -42,46 +34,10 @@ func (k Keeper) AllocateTokens(
 		return
 	}
 
-	// calculate fraction votes
-	previousFractionVotes := math.LegacyNewDec(sumPreviousPrecommitPower).Quo(math.LegacyNewDec(totalPreviousPower))
-
-	// calculate previous proposer reward
-	baseProposerReward := k.GetBaseProposerReward(ctx)
-	bonusProposerReward := k.GetBonusProposerReward(ctx)
-	proposerMultiplier := baseProposerReward.Add(bonusProposerReward.MulTruncate(previousFractionVotes))
-	proposerReward := feesCollected.MulDecTruncate(proposerMultiplier)
-
-	// pay previous proposer
-	remaining := feesCollected
-	proposerValidator := k.stakingKeeper.ValidatorByConsAddr(ctx, previousProposer)
-
-	if proposerValidator != nil {
-		ctx.EventManager().EmitEvent(
-			sdk.NewEvent(
-				types.EventTypeProposerReward,
-				sdk.NewAttribute(sdk.AttributeKeyAmount, proposerReward.String()),
-				sdk.NewAttribute(types.AttributeKeyValidator, proposerValidator.GetOperator().String()),
-			),
-		)
-
-		k.AllocateTokensToValidator(ctx, proposerValidator, proposerReward)
-		remaining = remaining.Sub(proposerReward)
-	} else {
-		// previous proposer can be unknown if say, the unbonding period is 1 block, so
-		// e.g. a validator undelegates at block X, it's removed entirely by
-		// block X+1's endblock, then X+2 we need to refer to the previous
-		// proposer for X+1, but we've forgotten about them.
-		logger.Error(fmt.Sprintf(
-			"WARNING: Attempt to allocate proposer rewards to unknown proposer %s. "+
-				"This should happen only if the proposer unbonded completely within a single block, "+
-				"which generally should not happen except in exceptional circumstances (or fuzz testing). "+
-				"We recommend you investigate immediately.",
-			previousProposer.String()))
-	}
-
 	// calculate fraction allocated to validators
+	remaining := feesCollected
 	communityTax := k.GetCommunityTax(ctx)
-	voteMultiplier := math.LegacyOneDec().Sub(proposerMultiplier).Sub(communityTax)
+	voteMultiplier := math.LegacyOneDec().Sub(communityTax)
 
 	// allocate tokens proportionally to voting power
 	// TODO consider parallelizing later, ref https://github.com/cosmos/cosmos-sdk/pull/3099#discussion_r246276376

x/distribution/keeper/allocation_test.go

@@ -134,21 +134,26 @@ func TestAllocateTokensToManyValidators(t *testing.T) {
 			SignedLastBlock: true,
 		},
 	}
-	distrKeeper.AllocateTokens(ctx, 200, 200, valConsAddr2, votes)
+	distrKeeper.AllocateTokens(ctx, 200, votes)
 
 	// 98 outstanding rewards (100 less 2 to community pool)
-	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(465, 1)}}, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[0]).Rewards)
-	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(515, 1)}}, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[1]).Rewards)
+	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(490, 1)}}, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[0]).Rewards)
+	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(490, 1)}}, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[1]).Rewards)
+
 	// 2 community pool coins
 	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: math.LegacyNewDec(2)}}, distrKeeper.GetFeePool(ctx).CommunityPool)
-	// 50% commission for first proposer, (0.5 * 93%) * 100 / 2 = 23.25
-	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(2325, 2)}}, distrKeeper.GetValidatorAccumulatedCommission(ctx, valAddrs[0]).Commission)
+
+	// 50% commission for first proposer, (0.5 * 98%) * 100 / 2 = 23.25
+	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(2450, 2)}}, distrKeeper.GetValidatorAccumulatedCommission(ctx, valAddrs[0]).Commission)
+
 	// zero commission for second proposer
 	require.True(t, distrKeeper.GetValidatorAccumulatedCommission(ctx, valAddrs[1]).Commission.IsZero())
-	// just staking.proportional for first proposer less commission = (0.5 * 93%) * 100 / 2 = 23.25
-	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(2325, 2)}}, distrKeeper.GetValidatorCurrentRewards(ctx, valAddrs[0]).Rewards)
-	// proposer reward + staking.proportional for second proposer = (5 % + 0.5 * (93%)) * 100 = 51.5
-	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(515, 1)}}, distrKeeper.GetValidatorCurrentRewards(ctx, valAddrs[1]).Rewards)
+
+	// just staking.proportional for first proposer less commission = (0.5 * 98%) * 100 / 2 = 24.50
+	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(2450, 2)}}, distrKeeper.GetValidatorCurrentRewards(ctx, valAddrs[0]).Rewards)
+
+	// proposer reward + staking.proportional for second proposer = (0.5 * (98%)) * 100 = 49
+	require.Equal(t, sdk.DecCoins{{Denom: sdk.DefaultBondDenom, Amount: sdk.NewDecWithPrec(490, 1)}}, distrKeeper.GetValidatorCurrentRewards(ctx, valAddrs[1]).Rewards)
 }
 
 func TestAllocateTokensTruncation(t *testing.T) {
@@ -235,7 +240,7 @@ func TestAllocateTokensTruncation(t *testing.T) {
 			SignedLastBlock: true,
 		},
 	}
-	distrKeeper.AllocateTokens(ctx, 31, 31, sdk.ConsAddress(valConsPk2.Address()), votes)
+	distrKeeper.AllocateTokens(ctx, 31, votes)
 
 	require.True(t, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[0]).Rewards.IsValid())
 	require.True(t, distrKeeper.GetValidatorOutstandingRewards(ctx, valAddrs[1]).Rewards.IsValid())

x/distribution/keeper/params.go

@@ -2,6 +2,7 @@ package keeper
 
 import (
 	"cosmossdk.io/math"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/distribution/types"
 )
@@ -39,17 +40,6 @@ func (k Keeper) GetCommunityTax(ctx sdk.Context) math.LegacyDec {
 	return k.GetParams(ctx).CommunityTax
 }
 
-// GetBaseProposerReward returns the current distribution base proposer rate.
-func (k Keeper) GetBaseProposerReward(ctx sdk.Context) math.LegacyDec {
-	return k.GetParams(ctx).BaseProposerReward
-}
-
-// GetBonusProposerReward returns the current distribution bonus proposer reward
-// rate.
-func (k Keeper) GetBonusProposerReward(ctx sdk.Context) (percent sdk.Dec) {
-	return k.GetParams(ctx).BonusProposerReward
-}
-
 // GetWithdrawAddrEnabled returns the current distribution withdraw address
 // enabled parameter.
 func (k Keeper) GetWithdrawAddrEnabled(ctx sdk.Context) (enabled bool) {

x/distribution/module.go

@@ -32,7 +32,7 @@ import (
 )
 
 // ConsensusVersion defines the current x/distribution module consensus version.
-const ConsensusVersion = 3
+const ConsensusVersion = 4
 
 var (
 	_ module.AppModule           = AppModule{}

x/distribution/simulation/params.go

@@ -13,9 +13,7 @@ import (
 )
 
 const (
-	keyCommunityTax        = "communitytax"
-	keyBaseProposerReward  = "baseproposerreward"
-	keyBonusProposerReward = "bonusproposerreward"
+	keyCommunityTax = "communitytax"
 )
 
 // ParamChanges defines the parameters that can be modified by param change proposals
@@ -27,15 +25,5 @@ func ParamChanges(r *rand.Rand) []simtypes.ParamChange {
 				return fmt.Sprintf("\"%s\"", GenCommunityTax(r))
 			},
 		),
-		simulation.NewSimParamChange(types.ModuleName, keyBaseProposerReward,
-			func(r *rand.Rand) string {
-				return fmt.Sprintf("\"%s\"", GenBaseProposerReward(r))
-			},
-		),
-		simulation.NewSimParamChange(types.ModuleName, keyBonusProposerReward,
-			func(r *rand.Rand) string {
-				return fmt.Sprintf("\"%s\"", GenBonusProposerReward(r))
-			},
-		),
 	}
 }

x/distribution/simulation/params_test.go

@@ -20,13 +20,11 @@ func TestParamChanges(t *testing.T) {
 		subspace    string
 	}{
 		{"distribution/communitytax", "communitytax", "\"0.120000000000000000\"", "distribution"},
-		{"distribution/baseproposerreward", "baseproposerreward", "\"0.280000000000000000\"", "distribution"},
-		{"distribution/bonusproposerreward", "bonusproposerreward", "\"0.180000000000000000\"", "distribution"},
 	}
 
 	paramChanges := simulation.ParamChanges(r)
 
-	require.Len(t, paramChanges, 3)
+	require.Len(t, paramChanges, 1)
 
 	for i, p := range paramChanges {
 		require.Equal(t, expected[i].composedKey, p.ComposedKey())