[Tokenomics] Implement Global Mint Reimbursement Request (#878)

## Summary

This PR adds
* GMRR TLM
* Ensures that the application has enough funds to cover for it.
* Deducts the total global mint amount from the application's stake.
* Sends the global mint amount from the application module account to
the tokenomics module account to the PNF account.
* The application still gets its global inflation share sent to its
account.

## Issue

- #732 

## Type of change

Select one or more from the following:

- [x] New feature, functionality or library

## Testing

- [x] **Unit Tests**: `make go_develop_and_test`
- [x] **LocalNet E2E Tests**: `make test_e2e`
- [ ] **DevNet E2E Tests**: Add the `devnet-test-e2e` label to the PR.

## Sanity Checklist

- [x] I have tested my changes using the available tooling
- [x] I have commented my code
- [x] I have performed a self-review of my own code; both comments &
source code
- [ ] I create and reference any new tickets, if applicable
- [x] I have left TODOs throughout the codebase, if applicable

---------

Co-authored-by: Daniel Olshansky <[email protected]>

e2e/tests/0_settlement.feature

@@ -6,7 +6,7 @@
 # that can be used to clear the state of the chain between tests.
 
 Feature: Tokenomics Namespace
-    Scenario: Settle the session when a valid claim is within max limits and a valid proof is submitted and required via threshold
+    Scenario: TLM Mint=Burn when a valid claim is within max limits and a valid proof is submitted and required via threshold
         # Baseline
         Given the user has the pocketd binary installed
         # Network preparation and validation
@@ -35,12 +35,13 @@ Feature: Tokenomics Namespace
         And the user should wait for the ClaimSettled event with "THRESHOLD" proof requirement to be broadcast
         # Validate the results
         # Please note that supplier mint is > app burn because of inflation
-        # TODO_TECHDEBT: Update this test such the the inflation is set and enforce that Mint=Burn
+        # TODO_TECHDEBT: Update this test such the inflation is set and enforce that Mint=Burn
         # Then add a separate test that only validates that inflation is enforced correctly
         Then the account balance of "supplier1" should be "898" uPOKT "more" than before
-        And the "application" stake of "app1" should be "840" uPOKT "less" than before
+        # The application stake should be less 840 * (1 + glbal_inflation) = 840 * 1.1 = 924
+        And the "application" stake of "app1" should be "924" uPOKT "less" than before
 
-    Scenario: Settle the session when a valid claim is create but not required
+    Scenario: TLM Mint=Burn when a valid claim is create but not required
         # Baseline
         Given the user has the pocketd binary installed
         # Network preparation and validation
@@ -70,9 +71,10 @@ Feature: Tokenomics Namespace
         And the user should wait for the ClaimSettled event with "NOT_REQUIRED" proof requirement to be broadcast
         # Validate the results
         # Please note that supplier mint is > app burn because of inflation
-        # TODO_TECHDEBT: Update this test such the the inflation is set and enforce that Mint=Burn
+        # TODO_TECHDEBT: Update this test such the inflation is set and enforce that Mint=Burn
         Then the account balance of "supplier1" should be "449" uPOKT "more" than before
-        And the "application" stake of "app1" should be "420" uPOKT "less" than before
+        # The application stake should be less 420 * (1 + glbal_inflation) = 420 * 1.1 = 462
+        And the "application" stake of "app1" should be "462" uPOKT "less" than before
 
     # TODO_TEST: Implement the following scenarios
     # Scenario: Supplier revenue shares are properly distributed

proto/poktroll/tokenomics/event.proto

@@ -79,4 +79,15 @@ message EventSupplierSlashed {
     // Amount slashed from the supplier's stake due to the expired claims.
     // This is a function of the number of expired claims and proof missing penalty.
     cosmos.base.v1beta1.Coin slashing_amount = 3;
+}
+
+// EventApplicationReimbursementRequest is emitted when an application requests
+// a reimbursement.
+message EventApplicationReimbursementRequest {
+    string application_addr = 1;
+    string supplier_operator_addr = 2;
+    string supplier_owner_addr = 3;
+    string service_id = 4;
+    string session_id = 5;
+    cosmos.base.v1beta1.Coin amount = 6;
 }

tests/integration/application/min_stake_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	cosmoslog "cosmossdk.io/log"
-	"cosmossdk.io/math"
 	cosmostypes "github.com/cosmos/cosmos-sdk/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	"github.com/stretchr/testify/require"
@@ -25,6 +24,7 @@ import (
 	sessiontypes "github.com/pokt-network/poktroll/x/session/types"
 	sharedtypes "github.com/pokt-network/poktroll/x/shared/types"
 	suppliertypes "github.com/pokt-network/poktroll/x/supplier/types"
+	tokenomicskeeper "github.com/pokt-network/poktroll/x/tokenomics/keeper"
 )
 
 type applicationMinStakeTestSuite struct {
@@ -51,7 +51,7 @@ func TestApplicationMinStakeTestSuite(t *testing.T) {
 }
 
 func (s *applicationMinStakeTestSuite) SetupTest() {
-	s.keepers, s.ctx = keeper.NewTokenomicsModuleKeepers(s.T(), cosmoslog.NewNopLogger())
+	s.keepers, s.ctx = keeper.NewTokenomicsModuleKeepers(s.T(), cosmoslog.NewNopLogger(), keeper.WithProofRequirement(false))
 
 	proofParams := prooftypes.DefaultParams()
 	proofParams.ProofRequestProbability = 0
@@ -235,7 +235,8 @@ func (s *applicationMinStakeTestSuite) getExpectedApp(claim *prooftypes.Claim) *
 	expectedBurnCoin, err := claim.GetClaimeduPOKT(sharedParams, relayMiningDifficulty)
 	require.NoError(s.T(), err)
 
-	expectedEndStake := s.appStake.Sub(expectedBurnCoin)
+	globalInflationAmt, _ := tokenomicskeeper.CalculateGlobalPerClaimMintInflationFromSettlementAmount(expectedBurnCoin)
+	expectedEndStake := s.appStake.Sub(expectedBurnCoin).Sub(globalInflationAmt)
 	return &apptypes.Application{
 		Address:                   s.appBech32,
 		Stake:                     &expectedEndStake,
@@ -304,8 +305,11 @@ func (s *applicationMinStakeTestSuite) assertUnbondingEndEventObserved(expectedA
 func (s *applicationMinStakeTestSuite) assertAppStakeIsReturnedToBalance() {
 	s.T().Helper()
 
-	expectedAppBurn := math.NewInt(int64(s.numRelays * s.numComputeUnitsPerRelay * sharedtypes.DefaultComputeUnitsToTokensMultiplier))
-	expectedAppBalance := s.appStake.SubAmount(expectedAppBurn)
+	expectedAppBurn := int64(s.numRelays * s.numComputeUnitsPerRelay * sharedtypes.DefaultComputeUnitsToTokensMultiplier)
+	expectedAppBurnCoin := cosmostypes.NewInt64Coin(volatile.DenomuPOKT, expectedAppBurn)
+	globalInflationCoin, _ := tokenomicskeeper.CalculateGlobalPerClaimMintInflationFromSettlementAmount(expectedAppBurnCoin)
+	expectedAppBalance := s.appStake.Sub(expectedAppBurnCoin).Sub(globalInflationCoin)
+
 	appBalance := s.getAppBalance()
 	require.Equal(s.T(), expectedAppBalance.Amount.Int64(), appBalance.Amount.Int64())
 }

tests/integration/tokenomics/relay_mining_integration_test.go

@@ -1,7 +1,6 @@
 package integration_test
 
 import (
-	"math"
 	"math/big"
 	"testing"
 
@@ -84,6 +83,7 @@ func TestComputeNewDifficultyHash_RewardsReflectWorkCompleted(t *testing.T) {
 		testutils.WithService(service),
 		testutils.WithApplication(application),
 		testutils.WithSupplier(supplier),
+		testutils.WithProofRequirement(false),
 	)
 	sdkCtx := sdk.UnwrapSDKContext(ctx)
 	sdkCtx = sdkCtx.WithBlockHeight(1)
@@ -94,13 +94,6 @@ func TestComputeNewDifficultyHash_RewardsReflectWorkCompleted(t *testing.T) {
 	err := keepers.SharedKeeper.SetParams(sdkCtx, sharedParams)
 	require.NoError(t, err)
 
-	// Set the global proof params so we never need a proof (for simplicity of this test)
-	err = keepers.ProofKeeper.SetParams(sdkCtx, prooftypes.Params{
-		ProofRequestProbability:   0,                                                                            // we never need a proof randomly
-		ProofRequirementThreshold: &sdk.Coin{Denom: volatile.DenomuPOKT, Amount: sdkmath.NewInt(math.MaxInt64)}, // a VERY high threshold
-	})
-	require.NoError(t, err)
-
 	// Update the relay mining difficulty so there's always a difficulty to retrieve
 	// for the test service.
 	_, err = keepers.ServiceKeeper.UpdateRelayMiningDifficulty(sdkCtx, map[string]uint64{service.Id: 1})

testutil/keeper/tokenomics.go

@@ -2,10 +2,11 @@ package keeper
 
 import (
 	"context"
+	"math"
 	"testing"
 
 	"cosmossdk.io/log"
-	"cosmossdk.io/math"
+	cosmosmath "cosmossdk.io/math"
 	"cosmossdk.io/store"
 	"cosmossdk.io/store/metrics"
 	storetypes "cosmossdk.io/store/types"
@@ -29,6 +30,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/pokt-network/poktroll/app"
+	"github.com/pokt-network/poktroll/app/volatile"
 	"github.com/pokt-network/poktroll/testutil/sample"
 	"github.com/pokt-network/poktroll/testutil/tokenomics/mocks"
 	appkeeper "github.com/pokt-network/poktroll/x/application/keeper"
@@ -117,7 +119,7 @@ func TokenomicsKeeperWithActorAddrs(t testing.TB) (
 	// Prepare the test application.
 	application := apptypes.Application{
 		Address:        sample.AccAddress(),
-		Stake:          &sdk.Coin{Denom: "upokt", Amount: math.NewInt(100000)},
+		Stake:          &sdk.Coin{Denom: "upokt", Amount: cosmosmath.NewInt(100000)},
 		ServiceConfigs: []*sharedtypes.ApplicationServiceConfig{{ServiceId: service.Id}},
 	}
 
@@ -126,7 +128,7 @@ func TokenomicsKeeperWithActorAddrs(t testing.TB) (
 	supplier := sharedtypes.Supplier{
 		OwnerAddress:    supplierOwnerAddr,
 		OperatorAddress: supplierOwnerAddr,
-		Stake:           &sdk.Coin{Denom: "upokt", Amount: math.NewInt(100000)},
+		Stake:           &sdk.Coin{Denom: "upokt", Amount: cosmosmath.NewInt(100000)},
 		Services: []*sharedtypes.SupplierServiceConfig{
 			{
 				ServiceId: service.Id,
@@ -199,6 +201,9 @@ func TokenomicsKeeperWithActorAddrs(t testing.TB) (
 	mockBankKeeper.EXPECT().
 		SendCoinsFromModuleToModule(gomock.Any(), tokenomicstypes.ModuleName, suppliertypes.ModuleName, gomock.Any()).
 		AnyTimes()
+	mockBankKeeper.EXPECT().
+		SendCoinsFromModuleToModule(gomock.Any(), apptypes.ModuleName, tokenomicstypes.ModuleName, gomock.Any()).
+		AnyTimes()
 
 	// Mock the account keeper
 	mockAccountKeeper := mocks.NewMockAccountKeeper(ctrl)
@@ -346,9 +351,9 @@ func NewTokenomicsModuleKeepers(
 	require.NoError(t, bankKeeper.SetParams(sdkCtx, banktypes.DefaultParams()))
 
 	// Provide some initial funds to the suppliers & applications module accounts.
-	err = bankKeeper.MintCoins(sdkCtx, suppliertypes.ModuleName, sdk.NewCoins(sdk.NewCoin("upokt", math.NewInt(1000000000000))))
+	err = bankKeeper.MintCoins(sdkCtx, suppliertypes.ModuleName, sdk.NewCoins(sdk.NewCoin("upokt", cosmosmath.NewInt(1000000000000))))
 	require.NoError(t, err)
-	err = bankKeeper.MintCoins(sdkCtx, apptypes.ModuleName, sdk.NewCoins(sdk.NewCoin("upokt", math.NewInt(1000000000000))))
+	err = bankKeeper.MintCoins(sdkCtx, apptypes.ModuleName, sdk.NewCoins(sdk.NewCoin("upokt", cosmosmath.NewInt(1000000000000))))
 	require.NoError(t, err)
 
 	// Construct a real shared keeper.
@@ -513,3 +518,33 @@ func WithProposerAddr(addr string) TokenomicsModuleKeepersOpt {
 		return sdkCtx
 	}
 }
+
+// WithProofRequirement is an option to enable or disable the proof requirement
+// in the tokenomics module keepers by setting the proof request probability to
+// 1 or 0, respectively whie setting the proof requirement threshold to 0 or
+// MaxInt64, respectively.
+func WithProofRequirement(proofRequired bool) TokenomicsModuleKeepersOpt {
+	return func(ctx context.Context, keepers *TokenomicsModuleKeepers) context.Context {
+
+		proofParams := keepers.ProofKeeper.GetParams(ctx)
+		if proofRequired {
+			// Require a proof 100% of the time probabilistically speaking.
+			proofParams.ProofRequestProbability = 1
+			// Require a proof of any claim amount (i.e. anything greater than 0).
+			proofRequirementThreshold := cosmostypes.NewInt64Coin(volatile.DenomuPOKT, 0)
+			proofParams.ProofRequirementThreshold = &proofRequirementThreshold
+		} else {
+			// Never require a proof probabilistically speaking.
+			proofParams.ProofRequestProbability = 0
+			// Require a proof for MaxInt64 claim amount (i.e. should never trigger).
+			proofRequirementThreshold := cosmostypes.NewInt64Coin(volatile.DenomuPOKT, math.MaxInt64)
+			proofParams.ProofRequirementThreshold = &proofRequirementThreshold
+		}
+
+		if err := keepers.ProofKeeper.SetParams(ctx, proofParams); err != nil {
+			panic(err)
+		}
+
+		return ctx
+	}
+}

x/tokenomics/keeper/settle_pending_claims.go

@@ -1,13 +1,15 @@
 package keeper
 
 import (
+	"context"
 	"fmt"
 
 	"cosmossdk.io/math"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/types/query"
 
 	"github.com/pokt-network/poktroll/app/volatile"
+	apptypes "github.com/pokt-network/poktroll/x/application/types"
 	prooftypes "github.com/pokt-network/poktroll/x/proof/types"
 	servicekeeper "github.com/pokt-network/poktroll/x/service/keeper"
 	sharedtypes "github.com/pokt-network/poktroll/x/shared/types"
@@ -35,6 +37,15 @@ func (k Keeper) SettlePendingClaims(ctx sdk.Context) (
 		return settledResult, expiredResult, err
 	}
 
+	// Capture the applications initial stake which will be used to calculate the
+	// max share any claim could burn from the application stake.
+	// This ensures that each supplier can calculate the maximum amount it can take
+	// from an application's stake.
+	applicationInitialStakeMap, err := k.getApplicationInitialStakeMap(ctx, expiringClaims)
+	if err != nil {
+		return settledResult, expiredResult, err
+	}
+
 	blockHeight := ctx.BlockHeight()
 
 	logger.Info(fmt.Sprintf("found %d expiring claims at block height %d", len(expiringClaims), blockHeight))
@@ -176,8 +187,11 @@ func (k Keeper) SettlePendingClaims(ctx sdk.Context) (
 		// 1. The claim does not require a proof.
 		// 2. The claim requires a proof and a valid proof was found.
 
+		appAddress := claim.GetSessionHeader().GetApplicationAddress()
+		applicationInitialStake := applicationInitialStakeMap[appAddress]
+
 		// Manage the mint & burn accounting for the claim.
-		if err = k.ProcessTokenLogicModules(ctx, &claim); err != nil {
+		if err = k.ProcessTokenLogicModules(ctx, &claim, applicationInitialStake); err != nil {
 			logger.Error(fmt.Sprintf("error processing token logic modules for claim %q: %v", claim.SessionHeader.SessionId, err))
 			return settledResult, expiredResult, err
 		}
@@ -402,3 +416,34 @@ func (k Keeper) slashSupplierStake(
 
 	return nil
 }
+
+// getApplicationInitialStakeMap returns a map from an application address to the
+// initial stake of the application. This is used to calculate the maximum share
+// any claim could burn from the application stake.
+func (k Keeper) getApplicationInitialStakeMap(
+	ctx context.Context,
+	expiringClaims []prooftypes.Claim,
+) (applicationInitialStakeMap map[string]sdk.Coin, err error) {
+	applicationInitialStakeMap = make(map[string]sdk.Coin)
+	for _, claim := range expiringClaims {
+		appAddress := claim.SessionHeader.ApplicationAddress
+		// The same application is participating in other claims being settled,
+		// so we already capture its initial stake.
+		if _, isAppFound := applicationInitialStakeMap[appAddress]; isAppFound {
+			continue
+		}
+
+		app, isAppFound := k.applicationKeeper.GetApplication(ctx, appAddress)
+		if !isAppFound {
+			err := apptypes.ErrAppNotFound.Wrapf(
+				"trying to settle a claim for an application that does not exist (which should never happen) with address: %q",
+				appAddress,
+			)
+			return nil, err
+		}
+
+		applicationInitialStakeMap[appAddress] = *app.GetStake()
+	}
+
+	return applicationInitialStakeMap, nil
+}